Atypical presentation of cutaneous meningioma.

Cutaneous meningiomas are rare tumors of ectopic meningeal tissue in the dermis or subcutis and are most commonly located on the scalp and around the eyes, ears, nose, and mouth. We present a case of cutaneous meningioma with an unusual presentation on the upper arm, but with positivity for epithelial membrane antigen to support the diagnosis of meningioma. Lack of pancytokeratin AE1/3 and p63 allowed us to rule out a keratinocytic tumor, such as squamous cell carcinoma and basal cell carcinoma. The absence of smooth muscle actin, FXIIIa, CD163, and CD34 allowed us to rule out a leiomyoma, dermatofibroma, and vascular neoplasm respectively. Weak staining of S100 allowed us to rule out a perineuroma. The purpose of this case report is to increase awareness of a rare presentation of cutaneous meningioma not located within the scalp/face region. This may broaden its inclusion within differential diagnoses of neoplasms of uncertain behavior and encourage correct clinical diagnosis, thus improving treatment outcomes.