A Case of Folliculosebaceous Cystic Hamartoma on the Upper Back

Folliculosebaceous cystic hamartoma (FCH) is a recently recognized adnexal tumor and is composed of follicular, sebaceous and mesenchymal elements such as small vessels, adipocytes and neural component in the fibrous stroma. It usually presents as an exophytic papule or nodule on the central part of the face. We describe a 39-year-old woman with FCH on the right upper back, which is an unusual site. A biopsy specimen demonstrated a follicular structure in infundibuiar nature, sebaceous lobules attached to it, and compactly laminated fibrous stroma with an increased number of vessels in it. Immunohistochemically, many of the vessels in the stroma showed positive reaction for CD34, and Factor VIII.