Pathogenesis of EMA negative PR negative Microcystic Meningioma: A Case Report

A patient, aged 35 years female complained of headache. CT examination revealed a non-succable tumor at anterolateral aspect of dura. Tumor extended from the right cervicomedullary junction upto C7 level. Tumor was excised and multiple soft tissue pieces, together measuring 1.5×1×1 cm were cellected. All the pieces were sectioned. Tumor had a sieve-like and cyst-like appearance. Section showed a circumscribed globular tumor which consisted of proliferated bland spindle cells. Tumor had an edematous stroma and presented a microcystic appearance. The cells had elongated ovoid nuclei and mild eosinophilic cytoplasm. Several thin-walled vascular spaces were also seen in the tumor. Strong positive reaction was obtained with an anti-S100 antibody, suggesting a neural origin of tumor cells. Further, anti-Ki 67 antibody gave mild reaction (Ki67 index was 12%) suggesting benign neoplasm. Anti-CD 34 and anti-D2.40antibodies gave positive reactions (2+) with small blood vessels of the tumor. Keywords: Benign cystic neoplasm with similar behavior among various subtypes.