BACKGROUND: Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma consisting of dilated folliculosebaceous units invested in mesenchymal elements. These lesions have a striking predilection for the central face and scalp of adults. The vast majority of lesions present as 0.5-1.5-cm papules or exophytic nodules. A single case of giant FSCH has been reported on the upper back. METHODS: A 32-year-old woman presented with a (15 cm in greatest dimension) plaque-like, multinodular lesion on her left upper arm for several years. The lesion was clinically suspected to be a nevus sebaceus. RESULTS: The skin excision showed numerous dermal and subcutaneous dilated follicular structures with peripherally radiating sebaceous lobules, hair follicles, and surrounding mesenchymal elements consistent with FSCH. CONCLUSION: To our knowledge, this is the second case of giant FSCH. Our case is unique for its larger size, more plaque-like growth, and location on an extremity when compared to the seminal case of giant FSCH.
BACKGROUND:Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma consisting of dilated folliculosebaceous units invested in mesenchymal elements. These lesions have a striking predilection for the central face and scalp of adults. The vast majority of lesions present as 0.5-1.5-cm papules or exophytic nodules. A single case of giant FSCH has been reported on the upper back. METHODS: A 32-year-old woman presented with a (15 cm in greatest dimension) plaque-like, multinodular lesion on her left upper arm for several years. The lesion was clinically suspected to be a nevus sebaceus. RESULTS: The skin excision showed numerous dermal and subcutaneous dilated follicular structures with peripherally radiating sebaceous lobules, hair follicles, and surrounding mesenchymal elements consistent with FSCH. CONCLUSION: To our knowledge, this is the second case of giant FSCH. Our case is unique for its larger size, more plaque-like growth, and location on an extremity when compared to the seminal case of giant FSCH.