Sonographic appearance of an eccrine spiradenoma: A case report.

Eccrine spiradenoma is a rare, benign, adnexal skin tumor of the sweat gland, which may manifest in any part of the body. It is typically located in the dermal or the subcutaneous fat layer. Eccrine spiradenomas rarely progress to malignant transformation and only a few cases of malignant transformation have been reported. Due to its rarity, there have been few reports about the sonographic appearances of eccrine spiradenoma. We report the sonographic findings in one case of eccrine spiradenoma, located in the subcutaneous fat and the deep dermal layers of the upper arm in a middle-aged woman.