Leydig cell tumor in an elderly patient with complete androgen insensitivity syndrome

BACKGROUND: Androgen insensitivity syndrome (AIS) is usually diagnosed in phenotypically female patients at puberty with primary amenorrhea. Testicular tumors often develop in patients with AIS, Sertoli cell tumor and seminoma being the most common types. Leydig cell tumor in AIS is extremely rare. CASE: A large abdominal tumor developed in a 73-year-old female patient. Physical examination and cytogenetic analysis revealed that the patient was with complete AIS. The patient underwent the extirpation of bilateral gonads including the tumor, pelvic lymph nodes, omentum and appendix vermiformis. The pathological diagnosis was malignant Leydig cell tumor of the left testis. There was no invasion or dissemination grossly and histologically. There was no adjuvant radiation or chemotherapy performed. The post-operative course was uneventful. The patient showed no evidence of disease at the post-operative 1 month checkup. CONCLUSION: We reported an extremely rare case of malignant Leydig cell tumor developing in an elderly AIS patient.