An uncommon folliculosebaceous cystic hamartoma on the lower extremity.

BACKGROUND Folliculosebaceous cystic hamartomas (FSCH) are a recently recognized cutaneous hamartoma comprised of follicular, sebaceous and mesenchymal elements. Only nine cases have been previously reported. The authors present a case of FSCH on the lower extremity in addition to a literature review. OBJECTIVE To further characterize the clinical, histological and immunohistological features of FSCH. METHODS The clinical, histological and immunohistological features of FSCH were evaluated and the literature reviewed. RESULTS This lesion uncommonly presents as exophytic papules or nodules on the leg, and most commonly presents on the central part of the face. Clinical differential diagnoses included nevus, neurofibroma and adnexal tumour. The diagnostic microscopic features of infundibular cystic structures with attached sebaceous glands and characteristic stroma were present in all lesions. Many of the stromal spindle cells were CD34-positive. CONCLUSION The FSCH is a recently recognized hamartoma comprised of follicular, sebaceous and mesenchymal elements. Although reported only rarely, its incidence is likely much higher. In the present patient, the FSCH was located in femoral region, which is very rare.