Intracerebral schwannoma clinically and radiologically mimicking meningioma

Abstract

A case of intracerebral schwannoma (ICS) occurring in a 33-year-old woman is presented. The patient's history of headache, numbness, tingling and the recent development of weakness of the right upper extremity with right facial droop began during pregnancy. Magnetic resonance imaging (MRI) showed a 4 x 2 x 2 cm heterogeneous, gadolinium-enhanced mass at the left frontoparietal junction, with peritumoral edema and a dural-based attachment. During her pregnancy, the mass increased in size. The surgically resected specimen consisted of lobulated, somewhat gelatinous soft tissue. Microscopically, the tumor demonstrated classic biphasic Antoni type A and B patterns, admixed with degenerative changes. Immunohistochemically, the neoplastic cells were positive for S-100 protein (diffuse and strong), CD34 (primarily in Antoni B areas), glial fibrillary acidic protein (GFAP; weak and diffuse) and calretinin (mainly in Antoni A areas), while none was positive for CD31, estrogen and progesterone receptors, bcl-2, or epithelial membrane antigen (EMA). Ultrastructurally, basal laminae and Luse bodies were identified. The differential diagnosis includes fibrous meningioma, solitary fibrous tumor, and ICS. Twenty-seven cases of ICS were reviewed in which the histological diagnosis was confirmed immunohistochemically or ultrastructually, and the cases were summarized (including the present case). A combined use of immunostains (S-100 protein, EMA, CD34, and maybe calretinin) is of great help in distinguishing ICS from its histological mimickers.

Supratentorial Intracerebral Schwannoma : Its Fate and Proper Management

“…However, many authors have indicated that there is no pathognomonic sign for intraparenchymal schwannoma, and that it is impossible to distinguish them from other tumors, such as pilocytic astrocytoma, ganglioglioma, pleomorphic xanthoastrocytoma, and dysembryoplastic neuroepithelial tumor, with radiographic evidence only. Large intraparenchymal schwannomas have been mistaken for meningioma or high-grade glioma11,14).…”

“…Intracerebral schwannoma is mostly benign and can be readily cured by surgery2,8,14,15). Typically, the tumor is well demarcated and can be easily dissected from brain parenchyme in most cases2).…”

Posterior fossa vermian cystic schwannoma mimicking as pilocytic astrocytoma: A case report and literature review

“…Thus, either immunohistochemical or electron microscopic examination is crucial for the differential diagnosis. [23] In our patient, beside typical Antoni A and Antoni B areas, tumor cells were reactive for S100 protein, neuron specific enolase (NSE) and vimentin and negative for GFAP, supporting diagnosis of schwannoma.…”

Intracerebral Schwannoma

“…Thus, either immunohistochemical or electron microscopic examination is crucial for the differential diagnosis. 21 …”