Spectrum of Surgically Resected Lesions of the Cavernous Sinus: A Neuropathologic Audit

Abstract

Background The cavernous sinus is a complex space composed of extradural venous plexus within dural folds. Several important structures like the carotid artery, cranial nerves, and sympathetic nerve fibers traverse through this space. Radiological diagnosis may not be definitive and in the context of discordance between clinical and neuroimaging diagnosis, histopathological evaluation becomes essential for diagnosis and management. Literature on the pathological spectrum of lesions is scarce as, with a shift in the treatment paradigm, most small lesions of cavernous sinus are treated with radiosurgery. However, surgical management still plays a role for larger lesions and in radiologically ambiguous cases for planning the definitive management. Materials and Methods We retrospectively reviewed all surgically resected lesions of the cavernous sinus over the last two decades (1998-2019). The clinical presentation, neuroimaging features, and histopathological findings were reviewed. Lesions extending from sella and other adjacent areas were excluded. Results Thirty-eight cases of isolated cavernous sinus mass lesions were diagnosed over the last two decades (1998-2019). Cavernous hemangiomas (19 cases, 50%) constituted the most frequent pathology, followed by aspergilloma, meningioma, schwannoma, metastatic adenocarcinoma, chondrosarcoma, and chordoma. Overall, 29.4% (10/34) could not be accurately diagnosed on neuroimaging. Of these, four cases of cavernous hemangiomas were mistaken for either meningioma (three cases) or schwannoma (one case). Neither chordoma nor chondrosarcoma was suspected. Conclusion This is the first study in literature, enumerating the pathological and imaging spectrum of surgically resected cavernous sinus lesions. Cavernous hemangiomas, metastases and chordomas, and chondrosarcoma posed the greatest difficulty in diagnosis on neuroimaging and the reasons for the same are analyzed. In the context of clinical and neuroimaging discordance in diagnosis, pathological characterization becomes essential for appropriate and timely management.

Keywords: cavernous sinus; histopathology; imaging.

Fig. 1

Cavernous angioma. MR imaging shows left cavernous regional well-circumscribed lesion displaying brilliantly hyperintensity on T2WI and FLAIR image, iso to hypointense on T1WI ( A, B ) with exuberant enhancement on contrast administration ( C, D ) reminiscent of a meningioma. However central non-enhancing areas in the early phase ( C ) which enhanced in the delayed phase are characteristic of cavernous angioma. Histology revealed circumscribed, smooth-surfaced lesion ( E ) with characteristic back-to-back arranged thin venous channels with flattened endothelium ( F ) separated by thin fibrous stroma ( G ). ( E , MAT × 8; F : H&E × Ob. ×10; G , MAT × Obj. ×10). H&E, hematoxylin and eosin; MAT, Masson's trichrome; MR, magnetic resonance; WI, weighted imaging.

Fig. 2

Aspergilloma. CT scan plain ( A ), T1WI, T2WI and postcontrast images showing heterogeneous hyperdensity ( A ) at left cavernous sinus without bony destruction ( A, B ). It is hypointense on T2WI ( C ) with heterogenous postcontrast enhancement. Note the presence of edema in the left temporal parenchyma ( D ). The imaging diagnosis was meningioma. The lesion on histology revealed a granulomatous lesion extending along the dural wall ( F ) of the cavernous sinus. The giant cells had engulfed characteristic septate acute angled branching hyphae of Aspergillus spp . demonstrated by periodic acid–Schiff (PAS) ( G ) and Gomori's methenamine silver stains (GMS) ( H ). ( F , MAT × Obj. ×4; G , PAS stain × Obj. ×20; H , GMS stain × Obj. ×20). CT, computed tomography; MAT, Masson's trichrome; WI, weighted imaging.

Fig. 3

Meningioma. T2WI, T1WI, FLAIR, postcontrast and MRA showing right cavernous sinus hyperintense lesion on T2WI and FLAIR ( A–C ), isointense on T1WI ( B ) with uniform post-contrast enhancement ( D ) characteristic of meningioma. Note right cavernous ICA is stretched and narrowed on MRA ( A–D ). Histology reveals an angiomatous meningioma with several thick hyalinized vessels ( E ). The tumor cells reveal membranous labeling for EMA ( E , inset). ( E , H&E × Obj. ×40; F , EMA × Obj. ×40). H&E, hematoxylin and eosin; FLAIR, fluid-attenuated inversion recovery; MRA, magnetic resonance angiogram; WI, weighted imaging.

Fig. 4

Schwannoma. Left parasellar lesion hypointense on T1WI, T2WI, SWI, and postcontrast T1WI shows a heterogeneously hyperintense lesion on T2WI with cystic areas ( A, B ), and heterogenous post-contrast enhancement ( D ). SWI images are showing microbleeds ( C ) within the lesion characteristic of schwannoma ( A–D ). Histology reveals schwannoma with characteristic spindled cells with wavy nuclei arranged in compact and loose zones ( E ) with strong diffuse S-100 positivity confirming Schwannian origin ( F ). ( E , H&E × Obj. ×10; F , S-100 × Obj. ×20). H&E, hematoxylin and eosin; SWI, susceptibility weighted imaging; WI, weighted imaging.

Fig. 5

Adenocarcinoma. CT plain and contrast study shows a mildly hyperdense enhancing lesion in right parasellar lesion ( A, B ). On MRI, the lesion is hypointense on T2WI, isointense on T1WI showing uniform contrast enhancement ( C–E ). Imaging possibility considered was meningioma Histopathology revealed features of adenocarcinoma with neoplastic epithelial cells arranged in tubules and acini. (F, H&E × Obj. ×4) Immunostaining was strongly pan cytokeratin positive ( F ) and negative for pituitary adenoma markers (images not shown). ( F , H&E × Obj. ×20; F , inset: pan-cytokeratin × Obj. ×20). CT, computed tomography; H&E, hematoxylin and eosin; WI, weighted imaging.

Fig. 6

Chondrosarcoma. CT scan and bone windows show hypodense lesion with calcification and destruction of the left side of the clivus and sellar floor ( A, B ). The lesion is hypointense on T1WI ( C ), Hyperintense on T2WI with calcification with Postcontrast Enhancement.T2WI, VenoBOLD and postcontrast images of right cavernous sinus lesion ( A–F ). The possibility of schwannoma was considered on imaging. Histology revealed a chondroid neoplasm with chondrocytes within lacunae ( G ), displaying increased cellularity and mild atypia but low mitotic activity characteristic of low-grade chondrosarcoma ( H ). Tumor cells exhibiting strong S-100 positivity confirming chondroid origin ( I ). ( G , H&E × Obj. ×10; H , H&E × Ob. ×20; I , S100 × Obj. ×20). CT, computed tomography; H&E, hematoxylin and eosin; WI, weighted imaging.

Fig. 7

Chordoma. Left parasellar lesion on CT scan appears hypodense. Note the absence of any bony destruction ( A, B ). On MRI it is hyperintense on T2WI ( C ), hypointense on T1WI ( D ) with heterogenous post-contrast enhancement ( F ). Based on these features, the possibility of schwannoma was suspected. Histology revealed a lobulated tumor showing distinctive cells with epitheloid morphology arranged in chords separated by bubbly mucoid stroma and characteristic physaliphorous cells with abundant multivacuolated cytoplasm. ( F ), tumor cell express S-100 ( G ) and strong cytokeratin confirming the diagnosis of chordoma ( H ). ( F , H&E × Ob.40x; G , S100 × Obj.20; H , pan-cytokeratinxObj.20). CT, computed tomography; H&E, hematoxylin and eosin; MRI, magnetic resonance imaging; WI, weighted imaging.