Abstract

Meningiomas are benign, primarily localized brain tumors that rarely present extracranially. Here we present a case of a subcutaneous deposit of meningioma with an atypical clinical appearance, but classic histopathology. A 48 year-old female with a remote past medical history of a WHO Grade 1 right sphenoid/orbital meningioma presented to dermatology with an enlarging right forehead plaque. On physical exam, there was an erythematous annular dermal plaque with no overlying epidermal change. The clinical differential diagnosis included granuloma annulare or other granulomatous process. A punch biopsy demonstrated plump epithelioid cells arranged in whorls within the subcutis with rare focal calcifications. Immunohistochemical stains with EMA and vimentin were positive. Progesterone receptor staining demonstrated strong nuclear positivity and a diagnosis of subcutaneous deposit of meningioma was made. There was no obvious lymphatic involvement as highlighted with D2-40 immunohistochemical staining. An MRI revealed several stable intracranial meningiomas without evidence of progression or obvious extension. Other radiologic studies for metastases were unremarkable. Cutaneous meningiomas, although exceedingly rare, are the most common site of extraneural meningiomas, with an incidence of 1-2%. When encountered, they may present as firm, subcutaneous nodules resulting either from direct extension or a metastasis. Our case demonstrated the importance of biopsying concerning cutaneous lesions in patients with histories of meningiomas. Despite the atypical clinical presentation as an annular plaque mimicking granuloma annulare, immunohistochemical staining confirmed the diagnosis of a meningioma.

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