Intracerebral schwannoma clinically and radiologically mimicking meningioma

• Published in: Pathology international 2005-08, Vol.55 (8), p.514-519
• Main Authors: Takei, Hidehiro, Schmiege, Lorenz, Buckleair, Linda, Goodman, J. Clay, Powell, Suzanne Z.
• Format: Article
• Language: English
• Subjects: Adult; Antigens, CD34 - analysis; Brain Neoplasms - metabolism; Brain Neoplasms - pathology; Brain Neoplasms - ultrastructure; Calbindin 2; Diagnosis, Differential; dural‐based; Female; Frontal Lobe - chemistry; Frontal Lobe - pathology; Frontal Lobe - ultrastructure; Glial Fibrillary Acidic Protein - analysis; Humans; Immunohistochemistry; intracerebral schwannoma; Magnetic Resonance Imaging; Meningeal Neoplasms - metabolism; Meningeal Neoplasms - pathology; Meningeal Neoplasms - ultrastructure; Meningioma - metabolism; Meningioma - pathology; Meningioma - ultrastructure; Neurilemmoma - metabolism; Neurilemmoma - pathology; Neurilemmoma - ultrastructure; Parietal Lobe - chemistry; Parietal Lobe - pathology; Parietal Lobe - ultrastructure; Pregnancy; Pregnancy Complications, Neoplastic; S100 Calcium Binding Protein G - analysis; S100 Proteins - analysis; ultrastructure
• ISSN: 1320-5463; 1440-1827
• DOI: 10.1111/j.1440-1827.2005.01862.x

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 × 2 × 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.