Giant folliculosebaceous cystic hamartoma of the upper extremity.
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.


CONCLUSIONS
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.
Department of Pathology, University of Michigan Hospitals, Ann Arbor, MI 48109, USA.
David E
DE
Sturtz
David J
DJ
Smith
Marlene S
MS
Calderon
Douglas R
DR
Fullen
D000328:Adult; D001132:Arm / Q000473:pathology; D003560:Cysts / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D018859:Hair Follicle / Q000473:pathology*; D006222:Hamartoma / Q000473:pathology*; D006801:Humans; D012627:Sebaceous Glands / Q000473:pathology*; D012871:Skin Diseases / Q000473:pathology*