Incisional Endometriosis: Diagnosed by Fine Needle Aspiration Cytology

Incisional endometriosis (IE) is a rare entity reported in 0.03-1.08% of women following obstetric or gynecologic surgeries. Most cases reported in literature have appeared after cesarean sections and were often clinically mistaken for hernia, abscess, suture granuloma or lipoma. We hereby report a case of IE following a second trimester hysterotomy, which was diagnosed by fine needle aspiration cytology (FNAC). Our patient was 26 years old, presenting with a mass over anterior abdominal wall, associated with incapacitating pain during each menstrual cycle. FNAC showed epithelial cells, stromal cells and hemosiderin laden macrophages. Based on the typical history, clinical and cytological features, the diagnosis of IE was established. Wide surgical excision was done and the resulting rectus sheath defect was repaired. Patient was followed for 6 months during which time she was symptom free. This article also reviews the spectrum of cytological features and the rare possibility of malignant transformation that can occur in IE.