This copy is for personal use only. To order printed copies, contact [email protected] 795 NEUROLOGIC/HEAD AND NECK IMAGING Imaging Spectrum of Cavernous Sinus Lesions with Histopathologic Correlation Harsha Vardhan Mahalingam, MD Sunithi E. Mani, MD Cavernous sinuses are paired interconnected venous plexuses situ- Bimal Patel, MD ated in the floor of the middle cranial fossa on either side of the Krishna Prabhu, MCh sella turcica and sphenoid sinus. They are lined by dura mater and Mathew Alexander, DM consist of multiple venous channels within. The cavernous sinuses Girish M. Fatterpekar, MD are intimately related to the internal carotid artery and its associ- Geeta Chacko, MD ated sympathetic plexus, the oculomotor nerve, the trochlear nerve, the abducens nerve, and the ophthalmic nerve. Cavernous sinuses Abbreviations: CCF = carotid-cavernous fis- are connected to the orbit, the pterygopalatine fossa, the infratem- tula, CSF = cerebrospinal fluid, FLAIR = fluid- attenuated inversion recovery, ICA = internal poral fossa, the nasopharynx, and the posterior cranial fossa by carotid artery, IgG4 = immunoglobulin G4, various foramina, fissures, and canals in the skull base. A multitude WHO = World Health Organization of structures in close relation to the cavernous sinus give rise to a RadioGraphics 2019; 39:795–819 myriad of possible pathologic conditions that can be broadly classi- https://doi.org/10.1148/rg.2019180122 fied into (a) neoplastic, (b) vascular, (c) infective or inflammatory, or (d) miscellaneous lesions. These pathologic conditions can have Content Codes: overlapping clinical manifestations. Hence, imaging plays a cru- From the Departments of Radiology (H.V.M., cial role in identifying the disease, assessing its extent, providing a S.E.M.), Pathology (B.P., G.C.), Neurosurgery (K.P.), and Neurology (M.A.), Christian Medi- pertinent differential diagnosis to guide further management, and cal College, Ida Scudder Road, Vellore, Tamil suggesting a site or route for biopsy. MRI is the modality of choice Nadu 632004, India; and the Department of Radiology, NYU Langone Medical Center, New to depict the cavernous sinuses, with CT and digital subtraction an- York, NY (G.M.F.). Presented as an education giography playing supplementary roles in certain situations. In this exhibit at the 2017 RSNA Annual Meeting. Re- ceived March 31, 2018; revision requested May article, the cavernous sinus lesions encountered in our institution 24 and received July 15; accepted July 20. For during a 10-year period are reviewed. The purpose of the article this journal-based SA-CME activity, the authors, is to (a) describe the anatomy of the cavernous sinus; (b) dem- editor, and reviewers have disclosed no relevant relationships. Address correspondence to onstrate the multimodality imaging spectrum of a wide variety of S.E.M. (e-mail: [email protected]). pathologic conditions involving the cavernous sinus, correlating ©RSNA, 2019 with the histopathologic findings; (c) highlight important imaging clues for differential diagnosis; and (d) help the reader overcome SA-CME LEARNING OBJECTIVES potential pitfalls in interpretation. After completing this journal-based SA-CME Online supplemental material is available for this article. activity, participants will be able to: © ■■Describe the anatomy of the cavernous RSNA, 2019 • radiographics.rsna.org sinus. ■■Identify the imaging features of a wide variety of cavernous sinus lesions. ■■Recognize imaging clues for differential Introduction diagnosis, and avoid pitfalls in interpreta- Cavernous sinuses are paired complex venous spaces situated on tion. either side of the sphenoid sinus and the sella turcica and are at the See rsna.org/learning-center-rg. crossroads of many crucial neurovascular structures. The internal carotid artery (ICA) and the abducens nerve travel within the cavity of the cavernous sinus; and the oculomotor nerve (cranial nerve III), the trochlear nerve (cranial nerve IV), and the ophthalmic nerve (cranial nerve V1) travel in the lateral wall of the cavernous sinus. The maxillary nerve (cranial nerve V2) courses just inferior to the 796 May-June 2019 radiographics.rsna.org TEACHING POINTS Diverse pathologic conditions of this region can, however, have similar clinical features; and ■■ Cavernous sinuses are paired complex venous spaces situated imaging plays a crucial role in confirming the on either side of the sphenoid sinus and the sella turcica and are at the crossroads of many crucial neurovascular structures. presence of disease, assessing its extent, guid- The internal carotid artery (ICA) and the abducens nerve trav- ing further investigations, and planning therapy el within the cavity of the cavernous sinus; and the oculomo- (medical management, microsurgery, endovascular tor nerve (cranial nerve III), the trochlear nerve (cranial nerve surgery, or radiation therapy). MRI is the imaging IV), and the ophthalmic nerve (cranial nerve V1) travel in the modality of choice for assessment of the cavernous lateral wall of the cavernous sinus. sinus, owing to the superior contrast resolution of ■■ The cavernous sinus can be affected by neoplasms (benign or malignant), infection or inflammation, vascular pathologic MRI. CT and digital subtraction angiography are conditions, and congenital lesions, among others. Diverse useful in certain cases. A thorough knowledge of pathologic conditions of this region can, however, have simi- anatomy, awareness of the imaging appearance of lar clinical features; and imaging plays a crucial role in con- the wide variety of lesions that can possibly involve firming the presence of disease, assessing its extent, guiding this region, and correlation with clinical and further investigations, and planning therapy (medical man- agement, microsurgery, endovascular surgery, or radiation histopathologic features are essential for providing therapy). MRI is the imaging modality of choice for assess- appropriate patient care. We review the anatomy ment of the cavernous sinus, owing to the superior contrast of the cavernous sinus, along with the imaging resolution of MRI. CT and digital subtraction angiography are technique, the multimodality imaging features of useful in certain cases. individual pathologic conditions of the cavernous ■■ Common neoplasms that involve the cavernous sinus include sinus correlating with histopathologic findings, pituitary adenoma, meningioma, nerve sheath tumors, head an algorithmic imaging approach to differential and neck malignancies such as nasopharyngeal carcinoma, and metastases. These neoplasms can be classified on the ba- diagnosis, and imaging pitfalls. sis of the origin or epicenter of the lesion as (a) lesions that arise primarily within the cavernous sinus, (b) lesions that Anatomy invade the cavernous sinus from adjacent structures, and Each of the paired cavernous sinuses is a ve- (c) metastatic or hematologic disease. nous lake situated lateral to the sella turcica, ■ ■ Vascular lesions of the cavernous sinus—namely, cavernous the pituitary gland, and the sphenoid sinus and sinus thrombosis, ICA aneurysm, and CCF—are great clinical mimics, with a wide variety of clinical manifestations varying medial to the medial aspect of the temporal lobe from trivial to life threatening. Among this category of cavern- of the brain. The term cavernous sinus was first ous sinus lesions, septic thrombosis is the most common and used by Winslow in 1734 owing to the multiple is managed primarily by controlling the source of sepsis with filaments, or septa, within, which gave it a cavern- medical and surgical means. Digital subtraction angiography ous or plexiform appearance. However, this term plays an important role in the management of CCF and ICA aneurysm. has courted controversy because the cavernous sinus has certain anatomic differences from other ■■ Considerable overlap exists in the radiologic findings of cav- ernous sinus involvement in infective or inflammatory diseas- dural venous sinuses. It is extradural in location, es; the most common findings encountered are a bulky cav- contains fat, and is continuous with the epidural ernous sinus and increased enhancement, which may extend space (extradural space) of the spine (by way of to the orbit or the adjacent dura. Imaging clues that point to the periosteum of the skull base) and the orbital infection or inflammation as the possible cause, as compared space, in contrast to other dural venous sinuses with neoplasms, are a sheetlike configuration of the abnormal soft tissue and T2 hypointensity. However, certain neoplasms, that are located between the two dural layers. such as lymphoma and en plaque meningioma, can mimic Parkinson (1) has argued that the cavernous si- these findings. Among this spectrum of infective and inflam- nus should be more accurately called “the lateral matory disorders, Tolosa-Hunt syndrome is a diagnosis of sellar compartment.” Because the term cavernous exclusion; other disease processes are diagnosed by specific sinus is well established in the medical literature, serum or histopathologic biomarkers. it continues to be used widely to refer to this anatomic compartment. The cavernous sinus has been described as junction of the lateral and medial walls of the an “anatomic jewel box” owing to its complex- cavernous sinus. Pathologic conditions of the ity. Figure 1 is a diagram of a coronal section cavernous sinus can have various clinical conse- through the cavernous sinuses. The cavernous quences, ranging from subtle to devastating,