Pilomatricomas are usually benign and relatively common skin tumors which orginate from primitive cells of the hair matrix.The typical appearance of the tumor is usually soliter, firm, flesh-colored and asymptomatic nodule beneath the skin, and usually affects young individuals.In recent years, except for the typical clinical presentation, some atypical bulla-like lesions have been reported.It has been stated that mechanical irritation, pricking or blunt trauma could be the most likely contributing factors.Herein we report a 28 year-old man with bullous pilomatricoma which developed after a deltoid muscle rupture in the course of a weight-lifting exercise.To the best of our knowledge the lesion is the first example of bulla-like pilomatricoma induced by a muscle rupture.