Chondrosarcoma

Introduction

Skull base chondrosarcomas are rare tumors that account for 0.1% of primary intracranial neoplasms. Chondrosarcomas are thought to arise from mesenchymal cells or from embryonal cartilage remnants of synchondroses, in which the majority of cranial chondrosarcomas occur at the skull base (75%) in the paraclival region, and include the petroclival, petro-occipital, spheno-occipital, and sphenopetrosal synchondroses. These tumors often extend into the paranasal sinuses, middle fossa, and/or posterior fossa. The majority of these tumors are low to intermediate grade, with slow growth and low metastatic potential, and histologically are grouped into conventional, mesenchymal, clear cell, and dedifferentiated types. Primary treatment is surgical resection, in which radiation therapy, including fractionated radiation, stereotactic radiosurgery, proton beam, and heavy particle radiation, is typically used for subtotal resection and recurrent disease. In this chapter, we present a case of a patient with petroclival chondrosarcoma.

Example case

Chief complaint: right facial numbness, headaches, ataxia

History of present illness

A 72-year-old, right-handed man with a history of coronary artery disease, hypertension, and hypercholesterolemia presented with right facial numbness, headaches, and ataxia. He had a known right petroclival mass that was being followed with serial examinations. Over the past 6 months, the lesion had grown ( Fig. 67.1 ) with increasing headaches, right facial numbness but no pain, and ataxia in which he required a walker for balance.

Medications : Aspirin, lisinopril, atorvastatin.
Allergies : No known drug allergies.
Past medical and surgical history : Coronary artery disease, hypertension, hypercholesterolemia, coronary bypass, knee replacement.
Family history : No history of intracranial malignancies.
Social history : Retired military, no smoking or alcohol.
Physical examination : Awake, alert, oriented to person, place, time; Cranial nerves II to XII intact, except right V1 to V3 numbness; Moves all extremities with good strength; Cerebellar: Right to left finger-to-nose dysmetria, truncal ataxia.

	Peter Bullock, FRCS, MRCP, London Clinic, London, England	Franco DeMonte, MD, MD Anderson Cancer Center, Houston, TX, United States	Hirofumi Nakatomi, MD, PhD, University of Tokyo, Tokyo, Japan	Jamie J. Van Gompel, MD, Mayo Clinic, Rochester, MN, United States
Preoperative
Additional tests requested	Cardiology evaluation Speech pathology with swallow evaluation Right eye tarsorrhaphy	Audiogram (BAERs) CT/CTA Speech pathology with swallow evaluation and videostroboscopy Medicine evaluation Neurology evaluation	Audiogram (PTA/SDS/BAERs) Cerebral angiogram ENT evaluation for possible biopsy, facial, and swallowing function Ophthalmology	Audiogram CTA
Surgical approach selected	Infratentorial supracerebellar	Endonasal endoscopic with right transpterygoid extension	Right suboccipital craniotomy	Right suboccipital craniotomy with endoscopic assistance and suprameatal petrosectomy
Other teams involved during surgery	None	ENT, head and neck	ENT	+/– ENT
Anatomic corridor	Infratentorial retrosigmoid anterior to and above cerebellum	Endonasal transpterygoid	Right suboccipital, paratrigeminal and lateral cerebellomedullary fissure	Right suboccipital
Goal of surgery	Maximal safe resection, brainstem decompression	Diagnosis, brainstem decompression, maximal safe resection	Stage 1–removal of CPA, Stage 2–ENT to remove parapharyngeal, Stage 3–SRS for cavernous sinus; decompress trigeminal nerve	GTR, decompress brainstem
Perioperative
Positioning	Right lateral park bench	Supine with lateral head flexion and right rotation	Right lateral	Right lateral decubitus
Surgical equipment	Surgical navigation IOM (MEP, SSEP, BAERs, cranial nerves III–XI) Surgical microscope Ultrasonic aspirator	Surgical navigation IOM (BAERs, facial EMG) Endoscope Ultrasonic aspiratorMicrodebrider	Surgical navigation IOM (MEP, BAERs, facial EMG) Surgical microscope Ultrasonic aspirator Weck/AVM clips Microanastamosis set	Surgical navigation IOM (BAERs, cranial nerves V–VIII, X/XI) Surgical microscope Endoscopes with rigid arm
Medications	Steroids	None	Mannitol Steroids	Steroids
Anatomic considerations	Transverse/sigmoid sinuses, cerebellum, superior petrosal veins, cranial nerves V/VII–VIII, AICA	Sphenopalatine artery, sphenoid sinus, pituitary gland, parasellar/paraclival ICA, Eustachian tube, vidian nerve, maxillary nerve, mandibular nerve, cranial nerves VI and XII, jugular foramen	Cranial nerve V–XI and petrosal vein	ICA, cranial nerves VII–VIII
Complications feared with approach chosen	Hearing loss, facial weakness, facial numbness, corneal ulceration, facial pain, brainstem injury	Mobilizing critical neurovascular structures	Hearing decline and facial palsy	Hearing loss, facial weakness, abducens palsy, facial numbness
Intraoperative
Anesthesia	General	General	General	General
Skin incision	Retrosigmoid lazy S	None	Retrosigmoid lazy S	Retroauricular curvilinear
Bone opening	Right suboccipital	+/– right middle turbinate, right anterior/posterior ethmoidectomies, right medial maxillectomy, posterior inferior turbinate, posterior septectomy, large sphenoidotomy, lateral and medial pterygoid plates, right mid and lower clivectomy, petroclival synchondrosis/petrous/clivus	Right suboccipital, foramen magnum, condylar fossa, IAC	Right suboccipital
Brain exposure	CPA	Posterior fossa dura	Cerebellum, CPA	Cerebellum, CPA
Method of resection	Tarsorrhapy prior to procedure, right suboccipital craniotomy with exposure of edge of transverse and sigmoid sinuses staying above foramen magnum, curvilinear dural opening, drain CSF from cisterna magna, identify cranial nerves IX–XI/VII–VIII/and V, work between cranial nerves, can sacrifice veins of the superior and lateral surface of the cerebellum if needed, decompress tumor, attempt to dissect from brainstem, watertight dural closure, leave remnant for proton beam radiation	Left nasoseptal flap harvest and stored in maxillary sinus, right anterior/posterior ethmoidectomies, +/– right middle turbinate removal, medial maxillectomy, removal of posterior inferior turbinate, posterior septectomy, large sphenoidotomy, exposure of right vidian canal, ligation of pharyngeal artery within palatovaginal canal, ligation of sphenopalatine artery and exposure of PPF, access the ITF through fascial incision lateral to V2 branches, detachment of the inferior head of the lateral pterygoid muscle, removal of pterygoid plates, skeletonization of V2 and V3, U-shaped mucosal incision in posterior nasopharynx and longus capitis, limited right mid and lower clivectomy, skeletonization of the paraclival and laceral ICA segments, removal of thin bony plate between ICA and superior surface of Eustachian tube, fibrocartilaginous tissue at foramen lacerum is sharply incisioned to mobilize ICA superiorly, incise lateral most Eustachian tube to expose petroclival synchondrosis/petrous apex/medial jugular foramen, removal of bone of petroclival synchondrosis/petrous bone/clivus, resection of jugular tubercle as laterally as possible, multilayer closure with nasoseptal flap	Right suboccipital craniotomy, removal of foramen magnum and condylar fossa, Y-shaped dural opening, epidural continuous suction, dissect lateral cerebellomedullary fissure to see foramen of Luschka and paratrigeminal cistern, place electrodes to monitor cranial nerves VII and VIII, devascularize tumor from petro-tentorial angle, debulk tumor, dissect from brainstem and cerebellum, open IAC and debulk tumor, reconstruct IAC	Right suboccipital craniotomy, drain cisterns, remove intracranial portion of tumor, ENT to drill suprameatal tubercle, complete bony resection with the aid of endoscopes
Complication avoidance	Large bony opening, decompress CSF, identify cranial nerves, work anterior to cranial nerves VII and VIII, watertight dural closure	Nasoseptal flap, exposure and mobilization of ICA by identification key landmarks (vidian nerve, V3), multilayer closure, lumbar drain if dura compromised	Large bone opening including foramen magnum and condylar fossa, cranial nerve monitoring, debulk tumor before capsular dissection	Cranial nerve monitoring, large suboccipital craniotomy, endoscopic assistance
Postoperative
Admission	ICU	Floor	ICU	ICU
Postoperative complications feared	Swallowing dysfunction, CSF leak, facial weakness, hearing loss, facial pain, abducens weakness	Swallowing dysfunction, CSF leak, middle ear effusion, diplopia, facial weakness, hearing loss	Hearing loss, facial palsy, facial dysesthesias	Hearing loss, CSF leak, sixth nerve palsy, facial weakness, facial numbness
Follow-up testing	CT night of surgery MRI within 72 hours after surgery Speech/swallowing evaluation	MRI skull base within 24 hours after surgery Speech/swallowing evaluation Lumbar drain for 5 days if dura compromised	MRI/MRA/MRV within 72 hours after surgery	MRI 3 months after surgery
Follow-up visits	3 months after surgery	7–10 days after surgery	1 month after surgery	3 months after surgery
Adjuvant therapies recommended	Grade 1–proton beam therapy Grade 2–proton beam therapy Grade 3–proton beam therapy	Grade 1–observation Grade 2–observation if GTR, radiation for STR Grade 3–radiation +/– chemotherapy	Grade 1–observation, SRS if grows Grade 2–observation, SRS if grows Grade 3–observation, SRS if grows	Grade 1–observation if good resection Grade 2–proton beam therapy Grade 3–proton beam therapy