Diagnosis of endometriosis by fine-needle aspiration cytology

Endometriosis is a fairly common disease found in a variety of extrauterine locations. It primarily affects reproductive age women and has symptoms varying from occult to more specific complaints. Occasionally the lesions produce solid nodules and/or cysts that are clinically palpable and easily evaluated by fine needle aspiration (FNA). We describe three cases of endometriosis diagnosed by FNA. The patients ranged in age from 32 to 38 and reported cyclic symptoms of pain, bleeding, or change in mass size. Two patients presented with subcutaneous masses (one along the upper pubic ramus, the other in the lower abdomen) and had ultrasonically guided FNA. The third patient had a vaginal cuff mass sampled by transvaginal FNA. All cytologic smears contained characteristic sheets of epithelial cells and fragments of loosely arranged spindled stroma. One case also showed mild epithelial atypia and plump stromal cells. Hemosiderin-laden macrophages were found in only one case. The cytologic diagnoses were confirmed by tissue in all patients. Endometriotic nodules must be evaluated for possible malignant transformation and differentiated from other benign and malignant masses, especially when clinical symptoms are vague. FNA offers a safe and effective tool for identification of endometriosis and obviates the need for diagnostic surgical procedures in some patients.