History:

Smooth-muscle hamartoma is an uncommon, usually congenital cutaneous hyperplasia of the arrectores pilorum muscles. When it is acquired, it may be confused with Becker's nevus. Here, I  report a case of this rare tumour in a young boy which started several years ago as multiple small skin coloured papules that subsequently coalesced to form a large soft plaque on back of shoulder and it never looked like Becker's nevus. Diagnosis was confirmed on histopatholgy and patient was managed conservatively.