Unusual presentation of retroperitoneal leiomyosarcoma mimicking an adnexal tumor with highly elevated serum CA-19-9
A 77-year-old woman was admitted with vague lower abdominal fullness and pain over six months. Tingling sensation on her right lower extremity has been developed since two months ago. Her menopause occurred at age of 45 years and she has never taken any hormone replacement therapy.\nA hard, fixed, and non-tender mass as large as a man's fist was palpated in right lower abdomen on pelvic examination. Contrast-enhanced abdominal computerized tomography (CT) showed 9.4 × 6.3 × 5.1 cm sized lobulated mass in right pelvic cavity (). It was seen relatively high enhanced and heterogenic mass on CT and causing hydronephroureterosis as a result of direct invasion of the ureter. The liver and renal function tests, and tumor markers such as CA-125, carcinoembryonic antigen, and alpha-fetoprotein were normal except the highly elevated level of CA-19-9 (70,000 U/mL).\nUnder the general anesthesia, surgical exploration was performed on suspicion of an ovary-origin tumor. The uterus and both adnexa showed normal appearance, however a 9 × 6 × 5 cm sized spherical mass with clear margin was found around right internal iliac artery in right retroperitoneal space (). No enlargement of lymph nodes around the mass and metastasis were found. Intraoperative frozen section analysis suggested of a leiomyosarcoma. Radical surgical resection was done including total hysterectomy, both adnexectomy, and right pelvic lymph node sampling. Surgical excision was attempted in order to completely remove the tumor after dissecting mesenteric adhesion. However, the tumor was firmly adhered to the ureter as well as right internal iliac artery and the tissue of tumor crumbled very easily. Tearing of internal iliac vein that occurred during dissection the mass from the ureter and internal iliac vessels was repaired by vascular surgeon. Most of the prominent mass was removed and the operation was finished with inserting an internal ureteral stent in the right ureter to prevent leakage or stricture due to undiagnosed latent ureteral injury.\nPathologic examination revealed a high-grade leiomyosarcoma with spindle-shaped tumor cells arranged in fascicles with intermediate dysplasia and also rich mitotic cell division (). On immunohistochemical staining, the sample showed positive results for vimentin, smooth muscle actin, and desmin; on the contrary, the sample was negative for CD31, CD34, and S-100 protein test (). The tumor was surgically staged as stage IIB (T2b2 N0 M0) leiomyosarcoma.\nThe patient started late oral diet after 7 days of operation due to a mild paralytic ileus, and then exercised well and showed no symptoms or signs of postoperative complication until 20 days when she could discharge after the operation. We had scheduled postoperative radiation therapy considering the patient's general condition 4 weeks later after surgery. The radiation treatment with 3 dimensional conformal radiotherapy using a 10 MV photon beam (Varian, Palo Alto, CA, USA) was applied to the tumor bed and total dose of 5,040 cGy was administered with a fractionated daily dose of 180 cGy, five days a week. Serum CA-19-9 returned to normal level (25.85 U/mL) in the end of radiation therapy. She is currently alive 12 months after treatment without recurrence or metastasis.