Primary extracranial meningioma of the pelvis: a light microscopic, immunohistochemical, and ultrastructural study.

BACKGROUND: Extracranial meningiomas are rare tumors which have been described in head and neck. The occurrence in mediastinum and retroperitoneum is even rarer. This presented case records a unique location, a meningioma arising in pelvis.

CASE: A 52-year-old woman presented with an ovarian mass. The histology of the resected tumor revealed sheets of bland epithelioid cells arranged in prominent whorls with psammoma bodies typical of meningothelial meningioma. Immunohistochemical analysis demonstrated diffuse strong positivity for vimentin and epithelial membrane antigen (EMA). There was moderate reactivity for cytokeratin, estrogen (ER) and progesterone (PR) receptors. By electron microscopy, the tumor cells expressed desmosomes and abundant intermediate filaments.

CONCLUSION: According to our review of literature, this is the first reported case of a primary pelvic meningioma. Its benign appearance and 4-year disease-free survival without clinical or radiological evidence of intracranial disease favors the pelvis as the primary site.