16.2.1 Nasal Cavity

The nasal cavity is bounded by the bony pyriform aperture and the external framework of the nose (Fig. 16.1). The nasal cavity opens anteriorly through the skin-lined nasal vestibule into the nares and communicates posteriorly through the choanae with the nasopharynx (Fig. 16.2a). The nasal cavity is divided in the midline by the nasal septum, which includes both cartilaginous and bony components (Fig. 16.2b). The cartilage of the septum is quadrilateral in shape and is thicker at its margins than at its center. Its anterior margin is connected with the nasal bones and is continuous with the anterior margins of the lateral cartilages; below, it is connected to the medial crura of the greater alar cartilages by fibrous tissue (Fig. 16.1). Its posterior margin is connected with the perpendicular plate of the ethmoid; its inferior margin is connected with the vomer and the palatine process of the maxilla.

On the lateral nasal wall are the superior, middle, and inferior nasal turbinates, and below and lateral to each turbinate (concha) is the corresponding nasal passage or meatus (Fig. 16.3). Above the superior turbinate is a narrow recess, the sphenoethmoidal recess, into which the sphenoid sinus opens. The superior meatus is a short oblique passage extending about halfway along the upper border of the middle turbinate; the posterior ethmoid cells open into the front part of this meatus. The middle meatus is below and lateral to the middle turbinate. The anatomy of the middle meatus is fully displayed by removing the middle turbinate.

The bulla ethmoidalis is the most prominent anterior ethmoid air cell. The hiatus semilunaris is a curved cleft lying below and in front of the bulla ethmoidalis. It is bounded inferiorly by the sharp concave margin of the uncinate process of the ethmoid bone and leads into a curved channel, the infundibulum, bounded above by the bulla ethmoidalis and below by the lateral surface of the uncinate process of the ethmoid. The anterior ethmoid air cells open into the front part of the infundibulum. The frontal sinus drains through the nasofrontal duct, which in approximately 50% of subjects will also drain into the infundibulum. However, when the anterior end of the uncinate process fuses with the front part of the bulla, this continuity is interrupted and the nasofrontal duct then opens directly into the anterior end of the middle meatus. Below the bulla ethmoidalis, partly hidden by the inferior end of the uncinate process, is the ostium of the maxillary sinus. An accessory ostium from the maxillary sinus is frequently present below the posterior end of the middle nasal concha. The inferior meatus is below and lateral to the inferior nasal turbinate. The nasolacrimal duct opens into the inferior meatus under cover of the anterior part of the inferior turbinate.

The roof of the nasal cavity is narrow from side to side and slopes downward (at about a 30° angle) from front to back. The cribriform plate, which transmits the filaments of the olfactory nerve, forms the roof of the nasal cavity medial to the superior attachment of the middle turbinate. Lateral to the middle turbinate, the fovea ethmoidalis forms the roof of the ethmoid sinuses. Careful assessment of the anatomy of the nasal roof, especially the relationship of the cribriform plate to the fovea ethmoidalis, is critical in avoiding a cerebrospinal fluid (CSF) leak during transnasal surgery in this region. The cribriform plate is usually at a slightly lower horizontal plane than the fovea ethmoidalis, forming a shallow olfactory groove. This configuration is described as Keros type I (Fig. 16.4). However, the cribriform plate may be moderately or significantly lower than the fovea ethmoidalis, resulting in a medium (Keros type II) or deep (Keros type III) olfactory groove. The topography of the roof may also be asymmetrical.1

The floor of the nasal cavity is concave from side to side and almost horizontal anteroposteriorly. The palatine process of the maxilla forms the anterior three-fourths, and the horizontal process of the palatine bone the posterior fourth, of the nasal floor (Fig. 16.2b).

The majority of the nasal cavity is lined by pseudostratified ciliated columnar epithelium, which contains mucous and serous glands (respiratory epithelium). Specialized olfactory epithelium lines the most superior portion of the nasal cavity and has direct connections with the olfactory tracts through openings in the cribriform plate.

The arteries of the nasal cavities are the anterior and posterior ethmoidal branches of the ophthalmic artery, which supply the ethmoid and frontal sinuses and the roof of the nose. The sphenopalatine artery supplies the mucous membrane covering the lateral nasal wall. The septal branch of the superior labial artery supplies the anteroinferior septum. The veins form a close cavernous plexus beneath the mucous membrane. This plexus is especially well marked over the lower part of the septum and over the middle and inferior turbinates. Venous drainage follows a pattern similar to arterial supply. The lymphatic drainage from the anterior part of the nasal cavity, similar to that of the external nose, is to the submandibular group of lymph nodes (Level I). Lymphatics from the posterior two-thirds of the nasal cavities and from the paranasal sinuses drain to the upper jugular (Level II) and retropharyngeal lymph nodes.

The sensory nerves of the nasal cavity transmit either somatoautonomic or olfactory sensation. Somatoautonomic nerves include the nasociliary branch of the ophthalmic, which supplies the anterior septum and lateral wall. The anterior alveolar nerve, a branch of the maxillary (V2), provides sensory innervation to the inferior meatus and inferior turbinate. The nasopalatine nerve supplies the middle of the septum. The anterior palatine nerve supplies the lower nasal branches to the middle and inferior turbinates. The nerve of the pterygoid canal (vidian) and the nasal branches from the sphenopalatine ganglion supply the upper and posterior septum and the superior turbinate. The olfactory nerve fibers arise from the bipolar olfactory cells and unite in fasciculi, which form a plexus beneath the mucous membrane and then ascend, passing into the skull through the foramina in the cribriform plate. Intracranially, olfactory nerve fibers enter the under surface of the olfactory bulb, in which they ramify and form synapses with the dendrites of the mitral cells of the olfactory tract.

16.2.2 Maxillary Sinus

The maxillary sinus (antrum of Highmore), the largest of the accessory sinuses of the nose, is a pyramidal cavity in the body of the maxilla (Fig. 16.5; Fig. 16.6). Its base is formed by the lateral wall of the nasal cavity, and its apex extends into the zygomatic process. Its roof or orbital wall is frequently ridged by the infraorbital canal, whereas its floor is formed by the alveolar process of the maxilla and is usually 1 to 10 mm below the level of the floor of the nose (Fig. 16.6). Projecting into the floor are several conical elevations corresponding with the roots of the first and second molar teeth; in some cases the floor is perforated by one or more of these roots. The natural ostium of the maxillary sinus is partially covered by the uncinate process and communicates with the lower part of the hiatus semilunaris of the lateral nasal wall (Fig. 16.3; Fig. 16.5). An accessory ostium is frequently seen in, or immediately behind, the hiatus. The maxillary sinus appears as a shallow groove on the medial surface of the bone about the fourth month of fetal life but does not reach its full size until after the second dentition.

16.2.3 Ethmoid Sinus

The ethmoidal air cells consist of numerous thin-walled cavities situated in the ethmoidal labyrinth and bounded by the frontal, maxillary, lacrimal, sphenoid, and palatine bones. They lie in the upper part of the nasal cavity, between the orbits (Fig. 16.6). The ethmoid sinuses are separated from the orbital cavity by a thin bony plate, the lamina papyracea. On either side they are arranged in three groups: anterior, middle, and posterior. The anterior and middle groups open into the middle meatus of the nose—the former by way of the infundibulum, the latter on or above the bulla ethmoidalis (Fig. 16.3). The posterior cells open into the superior meatus under cover of the superior nasal concha. Sometimes one or more ethmoid air cells extends over the orbital cavity (supraorbital ethmoid cells) or the optic nerve (Onodi cell). The ethmoidal cells begin to develop during fetal life.

16.2.4 Frontal Sinus

The paired frontal sinuses appear to be outgrowths from the most anterior ethmoidal air cells. They are situated behind the superciliary arches and are rarely symmetrical, and the septum between them frequently deviates to one or the other side of the midline. Absent at birth, the frontal sinuses are generally fairly well developed between the seventh and eighth years but reach their full size only after puberty. The frontal sinus is lined with respiratory epithelium and drains into the anterior part of the corresponding middle meatus of the nose through the nasofrontal duct, which traverses the anterior part of the labyrinth of the ethmoid. The soft tissues of the forehead are located anteriorly, the orbits are located inferiorly, and the anterior cranial fossa is located posteriorly (Fig. 16.3). Blood and neural supply is from the supraorbital and supratrochlear neurovascular bundles.

16.2.5 Sphenoid Sinus

The sphenoid sinus begins at the most posterior and superior portion of the nasal cavity (Fig. 16.3). This midline structure, which is contained within the body of the sphenoid bone, is irregular and often has an eccentrically located intersinus septum. When exceptionally large, the sphenoid sinus may extend into the roots of the pterygoid processes or great wings and may pneumatize the basilar part of the occipital bone. The sphenoid sinus ostium is located on the anterior wall of the sinus and communicates directly with the sphenoethmoidal recess above and medial to the superior turbinate. The sphenoid sinuses are present as minute cavities at birth, but their main development takes place after puberty. The posterosuperior wall of the sphenoid sinus displays the forward convexity caused by the floor of the sella turcica, which contains the pituitary gland.

The optic nerve and the internal carotid artery are closely related to the superior lateral wall of the sphenoid sinus, and their bony canals may be dehiscent within the sinus cavity (Fig. 16.7). Vascular and neural supplies come from the sphenopalatine and posterior ethmoidal arteries and the branches of the sphenopalatine ganglion, respectively.

16.2.6 Infratemporal Fossa

The infratemporal fossa is an irregularly shaped space situated below and medial to the zygomatic arch. It is bounded anteriorly by the posterior surface of the maxilla, superiorly by the greater wing of the sphenoid and the undersurface of the squamous portion of the temporal bone, medially by the lateral pterygoid plate, and laterally by the ramus of the mandible. It contains the inferior aspect of the temporalis muscle as well as the medial and lateral pterygoid muscles (Fig. 16.8). It also contains branches of the internal maxillary vessels, including the middle meningeal artery, and the mandibular (V3) nerves, including the lingual, inferior alveolar, and auriculotemporal nerves. The foramen ovale and foramen spinosum open on its roof and the alveolar canals on its anterior wall. The inferior orbital and pterygomaxillary fissures communicate with and may act as routes of spread of cancer to the infratemporal fossa. The infratemporal fossa also contains the upper carotid sheath, including the internal carotid artery, the internal jugular vein, and the last four cranial nerves.

16.2.7 Pterygopalatine Fossa

The pterygopalatine fossa is a small triangular space situated behind the maxillary sinus, in front of the pterygoid plates, and beneath the apex of the orbit. This fossa communicates with the orbit by the inferior orbital fissure, with the nasal cavity by the sphenopalatine foramen, and with the infratemporal fossa by the pterygomaxillary fissure (Fig. 16.5). Five foramina open into it, of which three are on the posterior walls: the foramen rotundum, the pterygoid canal, and the pharyngeal canal, in this order downward and medial. On the medial wall is the sphenopalatine foramen, and below is the superior orifice of the pterygopalatine canal. The fossa contains the maxillary nerve, the sphenopalatine ganglion, and the terminal part of the internal maxillary artery. The fissures and foramina of the pterygopalatine fossa serve as “highways” for spread of cancer from the sinonasal region to the orbit, infratemporal fossa, and cranial base.

16.2.8 Anterior Cranial Fossa

The floor of the anterior fossa is formed by the orbital plates of the frontal bone, the cribriform plate of the ethmoid, and the lesser wings and front part of the body of the sphenoid. In the midline it presents, from anterior to posterior, the frontal crest for the attachment of the falx cerebri; the foramen cecum, which usually transmits a small vein from the nasal cavity to the superior sagittal sinus (SSS); and the crista galli, the free margin of which affords attachment to the falx cerebri (Fig. 16.9).

On either side of the crista galli is the olfactory groove formed by the cribriform plate, which supports the olfactory bulb and presents foramina for the transmission of the olfactory nerves. Lateral to either olfactory groove are the internal openings of the anterior and posterior ethmoidal foramina. The anterior, situated about the middle of the lateral margin of the olfactory groove, transmits the anterior ethmoidal vessels and the nasociliary nerve. The nerve runs in a groove along the lateral edge of the cribriform plate. The posterior ethmoidal foramen opens at the back part of this margin under cover of the projecting lamina of the sphenoid and transmits the posterior ethmoidal vessels and nerve. More laterally, the cranial floor forms the orbital roof and supports the frontal lobes of the cerebrum. Further back, in the middle, are the planum sphenoidale, forming the roof of the sphenoid sinus, and the anterior margin of the chiasmatic groove, running laterally on either side to the upper margin of the optic foramen (Fig. 16.9).

16.2.9 Orbit

The orbits are two quadrilateral pyramidal cavities, their bases directed forward and lateral and their apices backward and medial so that their long axes diverge at a 45° angle and would meet over the body of the sphenoid if continued backward. The orbit is anatomically defined by seven bones (Fig. 16.10)—frontal, zygomatic, maxillary, lacrimal, ethmoid, sphenoid, and palatine—and by the orbital septum, which originates at the arcus marginalis, fusing with the levator aponeurosis above and the capsulopalpebral fascia below. It is bounded by the ethmoid and sphenoid sinuses at its medial aspect, the frontal sinus superomedially, the cranial vault superiorly and posteriorly, the temporal fossa laterally, and the maxillary sinus inferiorly. Each orbital cavity has a roof, a floor, a medial and a lateral wall, a base, and an apex.

The roof is formed anteriorly by the orbital plate of the frontal bone and posteriorly by the lesser wing of the sphenoid. It presents medially the trochlear fovea for the attachment of the cartilaginous pulley of the superior oblique muscle and laterally the lacrimal fossa for the lacrimal gland.

The floor is formed mainly by the orbital surface of the maxilla: anteriorly and laterally by the orbital process of the zygomatic bone and posterior and medially, to a small extent, by the orbital process of the palatine bone. At its medial angle is the superior opening of the nasolacrimal canal, immediately to the lateral side of which is a depression for the origin of the inferior oblique muscle. Running anteriorly near the middle of the floor is the infraorbital canal, ending anterior to the maxilla in the infraorbital foramen and transmitting the infraorbital nerve and vessels.

The medial wall is formed from anterior to posterior by the frontal process of the maxilla, the lacrimal bone, the lamina papyracea of the ethmoid, and a small part of the body of the sphenoid anterior to the optic foramen. Anteroinferiorly, the lacrimal sac is situated between the anterior and posterior lacrimal crests at the junction between the medial wall and the floor. The lacrimal part of the orbicularis oculi arises from the posterior lacrimal crest. At the junction of the medial wall and the roof, the frontoethmoidal suture presents the anterior and posterior ethmoidal foramina, the former transmitting the nasociliary nerve and anterior ethmoidal vessels and the latter the posterior ethmoidal nerve and vessels. These foramina indicate the level of the cranial base within the orbit.

The lateral wall is formed by the orbital process of the zygomatic and the orbital surface of the greater wing of the sphenoid. On the orbital process of the zygomatic bone are the orbital tubercle (Whitnall’s) and the orifices of one or two canals, which transmit the branches of the zygomatic nerve. Between the roof and the lateral wall, near the apex of the orbit, is the superior orbital fissure (SOF). Through this fissure the oculomotor, the trochlear, the ophthalmic division of the trigeminal (V1), and the abducent nerves enter the orbital cavity, as do also some filaments from the cavernous plexus of the sympathetic and the orbital branches of the middle meningeal artery. Passing posteriorly through the fissure are the ophthalmic vein and the recurrent branch from the lacrimal artery to the dura mater. The lateral wall and the floor are separated posteriorly by the inferior orbital fissure, which transmits the maxillary nerve (V2) and its zygomatic branch, the infraorbital vessels, and the ascending branches from the sphenopalatine ganglion.

The base of the orbit (orbital rim), quadrilateral in shape, is formed superiorly by the supraorbital arch of the frontal bone, in which is the supraorbital notch or foramen for the passage of the supraorbital vessels and nerve; inferiorly by the zygomatic bone and maxilla, united by the zygomaticomaxillary suture; laterally by the zygomatic bone and the zygomatic process of the frontal joined by the zygomaticofrontal suture; and medially by the frontal bone and the frontal process of the maxilla, united by the frontomaxillary suture.

The apex is situated in the posterior aspect of the orbit. The optic foramen is a short, cylindrical canal through which passes the optic nerve and ophthalmic artery.

The extraocular muscles—four rectus muscles and two obliques—control movement of the eye. Cranial nerve III innervates all but the lateral rectus and the superior oblique muscles, which are innervated by cranial nerves VI and IV, respectively. The rectus muscles originate at the annulus of Zinn and insert on the globe, forming a muscle cone, which is the central anatomic space in the orbit.

The lacrimal system comprises secretory and drainage systems. Secretory glands (the glands of Moll, Kraus, and Wolfring) may be found along the margin of the eyelid. The lacrimal gland, with its palpebral and orbital lobes, is located in the superotemporal orbit (Fig. 16.11). The lacrimal drainage system, located in the inferonasal orbit, is represented by the puncta, canaliculi, lacrimal sac, and nasolacrimal duct. Tumor involvement of the lacrimal system may present with epiphora.

The skin of the eyelid is continuous with the palpebral and bulbar conjunctivae, which are, in turn, contiguous with the globe. Each of these epithelial surfaces represents a potential site of origin for cancer.

16.3.1 Tumors of the Nasal Cavity and Paranasal Sinuses

The mucosal lining of the nose—the Schneiderian membrane—is derived from ectoderm. This is uniquely different from the mucosa of the rest of the upper respiratory tract, which is derived from endoderm. Olfactory neuroepithelium lines the superior portion of the nasal cavity and the roof of the nose and gives rise to neuroectodermal tumors, such as olfactory neuroblastoma and neuroendocrine carcinoma.2 ^,​ 3 ^,​ 4 The sinonasal epithelium also has minor salivary glands and gives rise to salivary gland tumors, such as adenoid cystic carcinoma and mucoepidermoid carcinoma.5 ^,​ 6 ^,​ 7 ^,​ 8 However, the most common epithelial neoplasms of the sinonasal tract are those arising from “metaplastic” squamous epithelium, namely squamous cell carcinoma, and those originating from the seromucinous glands of the mucosal lining, collectively known as adenocarcinomas.9 The unique histology of this region is reflected in the histogenesis of a complex variety of epithelial and non-epithelial tumors (Table 16.1). These tumors have a wide range of biologic behavior, and a few arise only in the sinonasal tract (e.g., inverted papilloma, olfactory neuroblastoma). Non-epithelial tumors are similar to those in other regions in the head and neck. The details of some of these tumors, such as squamous and nonsquamous carcinoma, melanoma, esthesioneuroblastoma, sarcomas, and angiofibromas and fibro-osseous lesion, are discussed in more detail in other chapters in Section III of the book.

Overall, sinonasal cancer accounts for about 1% of all malignancies and approximately 3% of cancers of the head and neck. It shows a male predominance (Fig. 16.12a) and a strong predilection for Caucasians (Fig. 16.12b). The majority of patients are older than 50 years at the time of diagnosis (Fig. 16.12c). The most common malignant tumor of the nasal cavity and paranasal sinuses is squamous cell carcinoma (Fig. 16.12d). Although the maxillary antrum is the most commonly involved sinus (Fig. 16.12e), anterior skull base invasion is most frequently encountered with malignant neoplasms of the nasal cavity and ethmoid sinus. Upward extension of these neoplasms toward the cribriform plate or fovea ethmoidalis is not uncommon, and it heralds intracranial extension.10 Primary carcinoma of the frontal sinus is uncommon, and those arising in the sphenoid sinus are rare.11 Unfortunately, despite significant improvement in diagnostic techniques such as nasal endoscopy and high-resolution imaging, most patients present with advanced-stage disease (Fig. 16.12f).

16.3.2 Tumors of the Orbit

The majority of malignant tumors involving the orbit represent direct extension of tumors of the sinonasal tract. Cancers arising primarily within the orbit are less common and may be classified broadly into pediatric and adult groups. Further subclassification may be according to site of origin or histologic type or both.

The most common intraocular tumor seen in children is retinoblastoma, which usually presents by age 3. Other common tumors in the orbit in children include rhabdomyosarcoma, neuroblastoma, lymphoma, and leukemia. Rhabdomyosarcoma is the most common primary and neuroblastoma the most common metastatic cancer to the orbit in children. Granulocytic sarcoma as a primary orbital neoplasm may precede or follow systemic leukemia. Primarily found in children with myelogenous leukemia, this tumor rarely occurs in adults.12

In adults, approximately 65% of orbital tumors are malignant. The most common benign tumors are vascular malformations and pleomorphic adenoma of the lacrimal gland. Malignant tumors of the lacrimal gland are most commonly lymphomas or tumors of salivary gland origin. Overall, lymphoma is the most common tumor of the orbit in adults. The main differential diagnoses are lymphoid hyperplasia and orbital pseudotumor. Malignant salivary gland tumors of the lacrimal gland include adenoid cystic carcinoma, malignant mixed cell tumor, and mucoepidermoid carcinoma. Neoplasms of the lacrimal sac include squamous cell carcinoma, adenocarcinoma, transitional cell carcinoma, salivary gland carcinoma, and poorly differentiated carcinoma. Cancer of the skin of the lid includes basal cell carcinoma, squamous cell carcinoma, sebaceous cell carcinoma, and malignant melanoma, any of which may invade the orbit. Tumors arising from the conjunctiva may also invade the orbit, including malignant melanoma, squamous carcinoma, and lymphoma. Choroidal melanoma is the most common intraocular malignancy and is biologically distinct from conjunctival or cutaneous melanoma.12

Primary intraorbital malignancies in adults are rare. Malignant neurogenic tumors of the orbit are uncommon, but those of peripheral nerve sheath origin predominate. They most commonly represent malignant degeneration in patients who have multiple benign neurofibromatosis. Other sarcomas that infrequently arise within the orbit include osteosarcoma, chondrosarcoma, malignant fibrous histiocytoma, hemangiopericytoma, and liposarcoma. Multiple myeloma may present in the orbit as a solitary plasmacytoma, or the orbit may be involved as part of disseminated disease. Hematogenous metastasis to the orbit most commonly originates from a primary in the lung or prostate in males. In females, carcinoma of the breast is the most common source of metastasis to the orbit.12

16.4.1 History and Clinical Examination

The signs and symptoms of early sinonasal tumors are very subtle and nonspecific. Early lesions are often completely asymptomatic or mimic more common benign conditions, such as chronic sinusitis, allergy, or nasal polyposis. Because early detection of sinonasal tumors is probably the most important factor in improving prognosis, a high degree of suspicion is necessary to diagnose smaller lesions. Common symptoms include nasal obstruction, “sinus pressure” or pain, nasal discharge that may be bloody, anosmia, or epistaxis. Failure of these symptoms to respond to adequate medical therapy or the presence of unilateral signs and symptoms should alert the physician to the possibility of malignancy and warrants further investigation using high-resolution imaging. Comprehensive examination of the nasal cavity should be done after topical decongestion and anesthesia using rigid or flexible endoscopy (Fig. 16.13; Video 16.1 and Video 16.2).

The presence of intranasal masses, ulcers, or areas of contact bleeding may indicate a malignant tumor. Although unilateral “polyps” may be inflammatory, they are more commonly neoplastic. Tumors may also present as submucosal masses without changes in the mucosa other than displacement. Any suspicious lesions should be biopsied, preferably after high-resolution imaging has been obtained to avoid severe bleeding and/or CSF leak, as discussed hereafter.

Extension of sinonasal tumors to adjacent structures renders the diagnosis obvious but is a late manifestation of the disease. Soft tissue swelling of the face may indicate tumor extension through the anterior bony confines of the nose and sinuses (Fig. 16.14).

Inferior extension toward the oral cavity may present with an ulcer or a submucosal mass in the palate or the alveolar ridge (Fig. 16.15). Middle ear effusion may indicate tumor involvement of the nasopharynx, Eustachian tube, pterygoid plates, or tensor veli palatini muscle. Extension to the skull base may lead to involvement of the cranial nerves, causing anosmia, blurred vision, diplopia, or hypoesthesia along the branches of the trigeminal nerves. The presence of associated neck masses usually represents metastatic disease in the cervical lymph nodes.

Orbital involvement is common in patients who have cancer arising from the ethmoid, maxillary sinuses, frontal, or sphenoid sinuses, in descending order of frequency. Less commonly, the orbit is involved with a primary tumor of the eye or its adnexa. Signs and symptoms of tumors in the orbit are usually due to mass effect or neuromuscular dysfunction. The patient may complain of proptosis, irregular shape of the eyelid, or blepharoptosis. Epiphora usually indicates involvement of the nasolacrimal duct (Fig. 16.11). Double vision may result from compression or infiltration of ocular nerves or muscles. Visual loss secondary to optic nerve involvement is usually a late sign, although more subtle signs of optic nerve dysfunction are more frequently encountered, among them afferent pupillary defect, loss of color vision, and visual field defect. Finally, orbital involvement may be asymptomatic and is discovered only on CT or MRI evaluation of patients who have sinonasal complaints.

Evaluation of patients who have suspected primary or secondary malignancy in the orbit should include a detailed neuro-ophthalmologic examination. This usually includes detailed assessment of visual acuity, visual fields, and ocular motility. Other ophthalmologic evaluation includes careful pupillary examination for afferent pupillary defect or anisocoria as well as external examination, including Hertel’s exophthalmometry and marginal reflex distance as an indicator of eyelid position. Slit lamp examination of the conjunctivae, cornea, anterior chamber, and lens is appropriate. Finally, detailed examination of the fundus may reveal compressive effect, intraocular malignancy, or an unrelated reason for visual loss. Formal testing of color vision and automated visual fields are commonly appropriate.

16.5.1 Indications

Imaging of the nasal cavity, paranasal sinuses, and orbit is indicated whenever there is clinical suspicion of a neoplastic process. Imaging is also indicated for obtaining pretreatment information regarding the location, size, extent, and invasiveness of the primary tumor, as well as the presence of regional and distant metastasis. Such information is crucial in deciding on therapeutic options and for proper preoperative planning of the optimal surgical approach. Imaging also plays an important role in posttreatment follow-up, indicating areas of residual or recurrent disease and defining suspicious areas for biopsy.

16.5.2 Imaging Modalities

Both CT and MRI may be needed for optimal radiologic assessment of sinonasal malignancy, particularly in assessing the cranial base, orbit, and pterygopalatine and infratemporal fossae. Coronal images best delineate involvement of the orbital walls and invasion of the skull base, particularly the cribriform plate. Axial images are particularly helpful in demonstrating tumor extension through the posterior wall of the maxillary sinus into the pterygopalatine fossa and infratemporal fossae. Sagittal images are particularly helpful in evaluating extension along the cribriform plate, planum sphenoidale, and clivus (Fig. 16.16). The main advantage of CT scans is in delineating the architecture of the bones, especially in “bone windows.”

The addition of contrast enhancement increases tumor definition from adjacent soft tissue, especially intracranially. Bone destruction and soft tissue invasion suggest an aggressive lesion, usually a malignant neoplasm. Widening or sclerosis of the foramina of the infraorbital, vidian, mandibular, or maxillary nerves may indicate perineural spread (Fig. 16.17).

MRI is unsurpassed in delineating soft tissue detail, both intra- and extracranially (Fig. 16.16). Obliteration of fat planes in the pterygopalatine fossa, infratemporal fossa, and nasopharynx usually indicates tumor transgression along these boundaries. Dural thickening or enhancement is usually an indication of tumor involvement, and evaluation of critical structures such as the brain and carotid artery is best delineated by MRI. Similarly, enhancement or thickening of cranial nerves indicates perineural spread, which is better detected on MRI than on CT (Fig. 16.17).13 Perhaps one of the most significant advantages of MRI is the ability to distinguish tumor from retained secretions secondary to obstruction of sinus drainage (Fig. 16.18).

MRI is also particularly helpful in monitoring patients during the postoperative follow-up period, although this role may be supplanted in the near future by PET scans because of their ability to distinguish between tumor recurrence and posttreatment fibrosis. PET-CT is also helpful in delineating regional and distant metastasis (Fig. 16.19).

Angiography is not indicated in the routine assessment of patients who have neoplasms of the nose, paranasal sinuses, and orbit. In certain selected cases, however, angiography may be necessary. These cases include vascular neoplasms of the sinonasal region, in which angiography not only delineates tumor’s extent and blood supply but also permit the use of selective embolization of the vascular supply to the tumor (Fig. 16.20). This reduces intraoperative blood loss, facilitating surgical resection.

16.6.1 Nasal Cavity and Paranasal Sinuses

The definitive diagnosis of a neoplasm of the nasal cavity and paranasal sinuses relies on expert histopathologic review of any biopsy specimens by a head and neck pathologist to confirm the exact diagnosis prior to treatment. This is critical, for the treatment and prognosis of sinonasal cancer is greatly influenced by histology.14

The vast majority of sinonasal neoplasms are accessible for biopsy through a strictly endonasal approach. A wide variety of rigid nasal endoscopes offer superb visualization of intranasal lesions with a high degree of optical resolution and bright illumination (Fig. 16.13). The application of topical anesthetics and decongestants improves visualization and allows thorough examination of the nasal cavity. The site of origin of the lesion and its relation to the nasal walls (septum, floor, roof, and lateral nasal wall) should be noted. An adequate specimen should be obtained, avoiding crushing of tissue, and should be submitted for histopathologic examination. If a diagnosis of lymphoma is suspected, fresh tissue should be sent in saline rather than fixed in formalin. Most endonasal biopsies can be performed in the outpatient setting with minimal discomfort to the patient. In certain cases, the diagnosis of a highly vascular neoplasm, such as angiofibroma, may be suspected on clinical grounds. Under these circumstances, it is prudent not to perform the biopsy until imaging and angiography (possibly with embolization) are performed (Fig. 16.20). Preoperative biopsy can then be performed in the operating room under controlled conditions to confirm the diagnosis before surgical resection. If a nasal mass is suspected to have an intracranial communication such as an encephalocele, meningocele, or nasal glioma, this should be confirmed with imaging so as to avoid inadvertent CSF leak and subsequent meningitis (Fig. 16.21).

16.6.2 Orbit

In most cases of primary intraorbital tumors, the approach used to obtain a biopsy is dictated by the location of the tumor. Lesions in the superior orbit may be addressed by a coronal flap or through a brow incision (modified Kronlein or Stallard-Wright incision). Lateral orbital lesions may require removal of the orbital rim. The transconjunctival approach, with detachment of the lateral canthal tendon, provides access to the orbital floor. The medial orbit may be entered through a modified Lynch-type or transcaruncular incision. Lesions within the muscle cone may be addressed by elevating conjunctiva and Tenon’s capsule from the globe and detaching the necessary rectus muscle. Lacrimal gland lesions are best approached through the upper lid crease.1

16.8.1 Indications and Contraindications

Surgery is indicated when there is adequate evidence that the tumor can be completely resected with acceptable morbidity. For early-stage disease (T1–T2), surgery alone may be adequate treatment, but for more advanced-stage resectable disease, postoperative adjuvant radiation or chemoradiation is commonly used to improve tumor control.15 The development of new combined craniofacial approaches has extended the indications of surgery to include some patients who have skull base and even intracranial extension.16 ^,​ 17 The advent of new reconstructive techniques, including microvascular free flaps, pericranial flaps, and prosthetic rehabilitation, has reduced morbidity and improved rehabilitation after extensive resection of advanced sinonasal cancer.18 ^,​ 19 ^,​ 20 In the presence of tumor extension to the cavernous sinus, internal carotid artery, or optic chiasm; extensive brain parenchymal involvement; or distant metastasis, surgery is usually contraindicated. However, in selected cases, surgery with proper adjuvant therapy may still offer the most effective local disease palliation even in the presence of extensive disease.