Sinonasal malignancies are a rare subset of malignancies of the upper aerodigestive tract which had been traditionally approached via open techniques. This article primarily addresses a paradigm shift in endoscopic endonasal oncological resection utilizing principles of tumor disassembly and negative margins. The surgical steps to these endoscopic techniques are detailed, emphasizing principles of sound oncological resection.
Key points
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The first chance is the best chance at an oncological cure.
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Partial resection or debulking has decreased patient overall survival.
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Piecemeal resection by tumor disassembly seems to have the same 5-year overall survival as traditional open approaches, with a marked reduction in morbidity and mortality.
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If negative margins cannot be obtained via an endoscopic approach, the surgeon must be prepared to switch to the appropriate procedures.
Sinonasal malignancies often present late because initial symptoms mimic benign disease. As a result, surgical resection can be extensive and carry a high risk due to the involvement of critical anterior cranial base structures. Traditionally, these advanced tumors were resected via potentially disfiguring open procedures with high morbidity (25%–35%) and mortality. The hallmark treatment is an open craniofacial resection (oCFR), first introduced by Ketcham in 1963. With the implementation of better imaging and technology, skull base surgery, is shifting toward less invasive approaches. Endoscopic resections are gaining traction, with early evidence showing equal outcomes and marked reduction in morbidity. A paradigm shift away from en bloc resection to piecemeal resection, or tumor disassembly, was seen by some as a large obstacle in this transition from open to endoscopic surgery. Opponents speculate that oncological integrity would be compromised by piecemeal resections. McCutcheon and colleagues demonstrated that patients who underwent a piecemeal oCFR were equivalent to patients who were treated with an en bloc oCFR. Proponents argue that resection of tumors involving the anterior skull base performed via an oCFR are rarely true en bloc resections. Other examples of effective piecemeal resection are transoral laser surgery and Mohs micrographic surgery, which yield acceptable results. Similarly, use of the endoscopic endonasal tumor disassembly can provide the same measure of oncological treatment as en bloc resection, if negative margins are achieved.
The endoscope is a tool that has eliminated line-of-sight issues previously encountered with open techniques while providing superior definition and contrast. The implementation of angled scopes has also allowed surgeons to minimize damage or removal of uninvolved structures, greatly decreasing the morbidity and complications of these techniques in select cases. Minimally invasive endoscopic resections (MIERs) have also been noted to have shorter operative time and decreased hospital stays as compared with their open counterparts. However, the team must have the expertise to convert to the appropriate open approach if the tumor cannot be resected endoscopically.
Presentation
Presenting symptoms are most commonly unilateral nasal obstruction, epistaxis, or nasal mass. Patients also present with symptoms of headache, epiphora, visual disturbance, anosmia, and nasal discharge. Unilateral symptoms are more common than bilateral symptoms. Patients with advanced disease also present with paresthesias or other cranial neuropathies. These nonspecific symptoms make early diagnosis challenging as they can be attributed to other common diseases such as chronic rhinosinusitis or atypical headaches. Further complicating diagnosis, nasal endoscopy can reveal a range of findings from smooth pedunculated lesions to friable masses.
Presentation
Presenting symptoms are most commonly unilateral nasal obstruction, epistaxis, or nasal mass. Patients also present with symptoms of headache, epiphora, visual disturbance, anosmia, and nasal discharge. Unilateral symptoms are more common than bilateral symptoms. Patients with advanced disease also present with paresthesias or other cranial neuropathies. These nonspecific symptoms make early diagnosis challenging as they can be attributed to other common diseases such as chronic rhinosinusitis or atypical headaches. Further complicating diagnosis, nasal endoscopy can reveal a range of findings from smooth pedunculated lesions to friable masses.
Workup
When a suspicious lesion is seen on endoscopy, the primary goal should be to distinguish a benign from malignant process. In most instances, an office biopsy is performed. The lesion is injected with Lidocaine hydrochloride 1 % and Epinephrine 1:100,000. If little bleeding occurs with this, a biopsy is taken. If a highly vascular lesion is suspected on endoscopy, or inadequate tissue is obtained, a biopsy is performed in the operating room after imaging is obtained with computed tomography (CT) and magnetic resonance imaging (MRI).
Debulking is avoided. Partial resections before planned oncological resections have been shown to produce poorer overall patient survival. Postoperative changes from partial resection result in fibrosis and edema, which makes delineation of gross tumor boundaries and attachment sites more difficult.
Radiologic assessment of the tumor is also important for staging; it helps to characterize if the lesion is resectable. A variety of imaging modalities can help to distinguish different aspects of the tumor ( Table 1 ). CT best identifies bony anatomy and bony erosion. MRI is an excellent modality to distinguish between soft tissue and inspissated secretions on T2-weighted images. Fluid-attenuated inversion recovery sequence is useful to differentiate cerebrospinal fluid from mucoceles and cystic or fluid contents. Periorbital invasion is best assessed on fat-suppressed images. Dura is best seen on T2-weighted images and postcontrast T1-weighted images. Nerve enhancement on T1-weighted images is helpful for perineural invasion.
| Imaging for Sinonasal Masses | ||
|---|---|---|
| Tumor Features | CT | MRI |
| Periorbital invasion & orbital fat | Bone erosion precisely shown by CT. The perorbia is not usually distinguished from tumor signal | T1-weighted and T2-weighted sequences |
| Dural invasion | Contrast is useful for large areas of dural invasion. Indirect signs (skull base erosion) can correlate with small areas of dural invasion | T2-weighted and postcontrast T1-weighted sequences |
| Perineural invasion | Limited to indirect signs (fat effacement or enlarged foramina) | Fat-saturated T1-weighted sequences with abnormal nerve enhancement |
| Distinguish retained mucous secretions | Cannot be assessed with this modality | T2-weighted sequences |
| Communication with cisterns | — | T2-weighted sequences |
| Assess course of internal carotid | CT angiography with Maximum Intensity Projections (MIP) reconstructions | — |
| Assess neck nodal disease | CT with contrast. | — |
The use of fluorodeoxyglucose PET has been limited in sinonasal malignant workups, as preliminary small population studies failed to demonstrate an advantage over combined CT and MRI modalities. In the posttreatment setting, it has been found to aid in early detection of locoregional recurrences and distant metastasis, complementary to MRI and CT.
Once a malignant lesion is confirmed, a metastatic workup is performed and a definitive treatment plan is formulated. These treatment decisions occur in conjunction with an interdisciplinary tumor board, weighing tumor histology, stage, surgical resection, and adjuvant and neoadjuvant treatment.
Sinonasal malignancies
Sinonasal malignancies account for approximately 3% of upper aerodigestive malignancies. Squamous cell carcinoma (SCC) is the most common sinonasal malignancy, accounting for 55% to 70% ( Fig. 1 ). Its most common location is the maxillary sinus (60%–70%), followed by the nasal cavity (20%–30%), ethmoid (10%–15%), and frontal and sphenoid sinus (1%). It has been associated with exposure to textile dust as well as smoking. SCC may have an ulceration-like appearance, and nonneoplastic processes such as infections and granulomatous diseases must be excluded.
Adenoid cystic carcinoma (ACC) is the second most common sinonasal malignancy and accounts for 10% to 15% of all head and neck cancers (See Fig. 1 ). This condition is most common in the maxillary sinus, followed by the nasal cavity. There are 3 histologic subtypes in which the solid pattern has a much poorer prognosis than the cribriform or tubular pattern. ACC has a propensity for perineural invasion, producing significant skull base and intradural extension in late stages. Initially, these patients have a high 5-year survival but poor 10- to 15-year survivals, with locoregional recurrence reported as high as 65%. Advanced disease is treated with surgery with adjuvant radiation.
Adenocarcinoma is the third most common sinonasal malignancy. It comprises about 8% to 15% of sinonasal malignancies (See Fig. 1 ). Its most common location is the ethmoid sinus (85%), and it is noted to have both a low- and high-grade subtype. It has been linked to woodworking as well as textile dust and is noted to be more common in men. It is often noted to involve the olfactory cleft, appearing as a polypoid neoplasm with well-defined boundaries. Treatment is surgical excision with adjuvant radiotherapy for advanced disease.
Malignant melanoma of the sinonasal cavity comprises less than 2% of all malignant melanoma. It has an extremely poor prognosis with a third of patients presenting with neck metastasis. The most common location is in the nasal cavity. It can appear grayish-blue-to-white or pink-to-black.
Comprising about 2% of sinonasal malignancies are esthesioneuroblastomas (ENBs), initially described by Berger and Luc in 1924 (See Fig. 1 ). This tumor is also known as olfactory neuroblastoma, phenotypically displaying a mix of a pure neural neoplasm and a neuroendocrine epithelial tumor. This rare neoplasm is estimated to have a prevalence of 0.4 cases per million individuals per year.
ENBs generally originate from the olfactory neuroepithelium, which is situated mainly on the cribriform plate, superior septum, and turbinate. Olfactory neuroepithelium can extend down onto the middle turbinate, with rare ectopic locations involving the inferior turbinate or maxillary sinus. ENBs are thought to originate from the basal progenitor cells of the olfactory neuroepithelium.
Sinonasal undifferentiated carcinoma (SNUC) is a rare, high-grade and locally aggressive malignancy of the sinonasal tract. It was first described in 1986 by Frierson and colleagues and is an aggressive ectodermally derived neoplasm originating from schneiderian epithelium in the nasal cavity and paranasal sinuses.
The cause of SNUC is unclear, and unlike undifferentiated nasopharyngeal carcinoma, recent literature does not support a definite association between SNUC and Epstein–Barr virus. There might be some correlation between smoking and SNUC, but no environmental or occupational carcinogen has been demonstrated to have strong correlation with SNUC.
The disease is more common in men, with a male/female ratio reported to be 2:1. SNUC affects patients with an extensive age range, third to ninth decade, but it is more common in the fifth and sixth decades of life.
Treatment
With small tumors, the goal should be identifying the attachment site and obtaining negative margins around this area. Larger tumors tend to have an element of expansive remodeling rather than frank erosion. During an oncological resection, the authors systematically disassemble the tumor as the attachment site is identified.
See Fig. 2 for operating room topography.
Preparing the nose
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Place pledgets bilaterally in the nasal cavity soaked in Cocaine hydrochloride 4% topical solution.
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Rotate the bed 180° away from the anesthesia cart, elevating the head of the bed to 30°.
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Place the head on a donut to prevent rotation of the head.
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Calibrate the image guidance system and ensure accuracy.
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Introduce a 0° endoscope, and inject lidocaine hydrochloride 1% with epinephrine 1:100,000 into the septum, inferior and middle turbinates, and ascending process of the maxilla.
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This injection decreases bleeding, and the septal injection assists in raising a nasoseptal flap later in the procedure if needed.
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Injection of the lateral walls anterior to the uncinate aids in decreased bleeding when instruments are repeatedly removed and inserted into the nasal cavity.
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If a nasoseptal flap is anticipated, it is often harvested at this point in time if uninvolved with tumor and stored in the nasopharynx.
Medial maxillectomy
If a small tumor can be removed en bloc, this is preferred. For a larger tumor, a medial maxillectomy is performed as follows ( Fig. 3 ):
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Drill along the nasal floor with a 4-mm self-irrigating diamond drill.
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Thus, the maxillary sinus should be connected via the inferior meatus to the nasal cavity.
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Extend this posteriorly to the posterior wall of the maxillary sinus and anteriorly to the nasolacrimal duct (the nasolacrimal duct is housed in the dense bone known as the ascending process of the maxilla).
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If pathology dictates, the authors resect the nasolacrimal duct anteriorly until the pyriform aperture with the 4-mm self-irrigating diamond drill.
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Endoscopically, the head of the inferior turbinate attachment marks the location of the pyriform aperture.
Related posts:
Endoscopic Endonasal Skull Base Surgery
Endoscopic Endonasal Extended Approaches for the Management of Large Pituitary Adenomas
Endoscopic Endonasal Repair of Spontaneous and Traumatic Cerebrospinal Fluid Rhinorrhea
Endoscopic Endonasal Approach to Ventral Posterior Fossa Meningiomas
Endoscopic Endonasal Odontoidectomy
Chordomas
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