Adenolipoma of the skin

Adenolipoma of the skin (ALS) is an uncommon histological variant of lipoma, characterized by the presence of normal eccrine sweat glands inside the fat proliferation. A 32-year-old woman presented to our department with a slow-growing, painless subcutaneous soft tumour located on the upper part of the right thigh. Microscopically, there was lobulated adipose tissue proliferation with well-differentiated eccrine glands and ducts in the periphery and centre of the nodule. These features were suggestive of ALS. ALS is a rare microscopic variant of cutaneous lipoma having similar clinical features to lipoma. The most frequent locations of this tumour are thighs (as in our patient), shoulders, chest and arms. Histologically, the tumour is composed of lobulated adipose tissue with larger and more prominent lobules than those in normal subcutaneous adipose tissue. A well-developed capsule may also be identified. Eccrine glands and ducts, without proliferative changes, are well-differentiated within the adipose tissue. Differential diagnosis of adenolipoma includes the common lipoma and its variants, skin tag and other hamartomatous lesions, such as nevus lipomatosus superficialis, and the lipomatous variant of eccrine angiomatous hamartoma.