Abstract Disclosure: A. Rehan: None. M. Pandey: None. I. Goyal: None. E. Punni: None. N. Shakir: None. Background: Steroid cell tumors of the ovary are a rare entity, constituting less than 0.1% of all ovarian tumors. These tumors can present with diverse endocrine and paraneoplastic effects, including androgen excess and polycythemia. Hyperandrogenism in females can lead to hirsutism, virilization, alopecia, menstrual irregularities, acne, and emotional changes, with complications including hyperlipidemia and insulin resistance. There are various causes of androgen excess in a female including polycystic ovary syndrome (PCOS), androgen-secreting tumors, Cushing’s syndrome, and congenital adrenal hyperplasia. In a postmenopausal woman displaying signs of androgen excess, one must consider androgen-secreting tumors, and even the rare ovarian steroid cell tumor as a possible cause. Clinical Case: A 62-year-old female with type 2 diabetes mellites, obstructive sleep apnea, anxiety and depression initially presented to her primary care provider with fatigue, light-headedness, and weight loss. Initial blood work done revealed a hemoglobin greater than 20 g/dL (NR 12-16) and hematocrit greater than 60% (NR 36-48), requiring several sessions of phlebotomy. Symptoms persisted and she was finally referred to a hematologist who noted physical exam findings of hirsutism and virilization, including temporal hair loss and excess facial/body hair growth. Other concerning signs included clitoromegaly, decrease in chest size, and deepening voice. Menopause had occurred at age 50, and the patient did not have any issues with fertility during her reproductive years. Biochemical evaluation revealed testosterone level of greater than 1500 ng/dL (NR 19-82) with normal sex hormone binding globulin level, DHEA-S 652 ug/dL (NR 29-220), appropriately suppressed FSH/ LH, and normal salivary cortisol levels. Tumor markers showed normal CEA, and alpha fetoprotein but elevated CA 125 to 80.5 U/ml (NR < 38.1). Pelvic ultrasound demonstrated a 12 cm heterogeneously echoic, vascular right adnexal mass concerning for ovarian malignancy. Pelvic MRI showed a 9.8 cm right sided cystic and solid adnexal mass. The patient underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy, peritoneal biopsies, and omentectomy. Pathology revealed a stage IA steroid cell tumor measuring 11.4 cm. After resection, the patient reported improvement in facial hair and fatigue. Labs showed normalization of hemoglobin, hematocrit, and testosterone levels. Conclusion: This rare case highlights the importance of considering steroid cell tumor as a cause of polycythemia with hyperandrogenism. Timely diagnosis and intervention play a critical role in preventing irreversible virilization, mitigating malignant risks, and, in certain instances, preserving fertility. Generally, the prognosis is favorable, and symptom and lab normalization is often achieved through surgical resection. Presentation: 6/2/2024