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

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.  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.  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.  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.