A 22-year-old woman presented with left pelvic pain and mass. Ultrasonography confirmed a multilocular left adnexal mass containing cysts of varying sizes. The patient had no pulmonary symptoms at the time of presentation. The mass was surgically excised and pathologic diagnosis of lymphangioleiomyomatosis (LAM) was made. Subsequently, she developed hemoptysis and pleural effusion. High-resolution computed tomography of the chest showed findings consistent with LAM. Early diagnosis and treatment for LAM was possible in this atypical case.