Sclerotic glomus tumor.

We report an unusual histopathological variant of a glomus tumor that arose in a peculiar topographic site, a sclerotic glomus tumor. Unlike conventional glomus tumors or glomangiomas that have a loose fibrous stroma with variable hyaline and myxoid changes, the case reported herein had a diffuse, hyalinized, sclerotic stroma. A further difference was that the majority of glomus tumors and glomangiomas occur in the subungual area, trunk, or extremities, whereas the present tumor occurred on the ear. Due to the peculiar histological features and location, other tumors were considered in the differential diagnosis to include Merkel cell carcinoma, primitive neuroectodermal tumor, and small cell melanoma. This article illustrates a unique variant of a glomus tumor, which to our knowledge has not been previously described.