Cutaneous spindle cell adenolipoma with eccrine and apocrine differentiation.

Cutaneous spindle cell adenolipoma (SCAL) is a recently described rare variant of lipoma with 11 cases reported to date. Here we report a consultation case of a 77-year-old male who presented with a nodule on the right nasolabial fold, diagnosed as apocrine fibroadenoma or sebaceous hyperplasia by an outside pathologist. The specimen revealed an ill-defined dermal tumor composed of mature adipocytes, bland spindle cells, ropey collagen, and dilated eccrine and apocrine glands and ducts in a fibromyxoid stroma. The spindle cells were positive for CD34 and negative for S100 protein and SOX10. These findings are consistent with those of cutaneous SCAL. The pathogenesis of this entity is controversial and includes a hamartomatous process, derivation from adipose tissue surrounding eccrine glands, or preexisting glands entrapment within a growing lipoma. In the present case, the glandular component is extensive and includes both eccrine and apocrine differentiation, which has not been previously described and further supports the hamartomatous nature. Awareness of this rare entity is helpful to prevent confusion with other look-alike primary and metastatic cutaneous lesions.