Dermoid cyst indenting bladder: a diagnostic dilemma

A dermoid cyst is a benign cutaneous developmental anomaly that arises from the entrapment of ectodermal elements along the lines of embryonic closure. These benign tumors are lined by stratified squamous epithelium with mature skin appendages found on their wall and their lumens filled with keratin, hair, teeth etc. They are usually benign in nature. Mature ovarian dermoid cysts are very common accounting for 25% of all benign ovarian neoplasms. Uncomplicated dermoid cysts are usually asymptomatic and easy to diagnose on imaging. Presentation of dermoid cysts are extremely rare in the urinary bladder and it is a diagnostic challenge to the gynecologist, pathologist and urologist. Only few cases are found and documented till now. We present an extremely rare case of dermoid cyst involving bladder in a 29 year old female who presented with chief complaint of pain abdomen associated with passage of hair through the urine since 2 months. Her cystoscopy showed presence of hair and caseous material on the surface of the lesion.