Primary Retroperitoneal Mucinous Cystadenocarcinoma in Males: A Case Report.

Primary retroperitoneal mucinous cystadenocarcinoma (PRMC) is a rare malignant neoplasm, predominantly reported in women, with occurrence in men being extremely uncommon. A handful of male cases have been described in the literature. The deep retroperitoneal location and nonspecific symptoms often delay diagnosis and complicate management. We report the case of a 69-year-old male presenting with a four-month history of abdominal discomfort and significant unintentional weight loss. Imaging with CT and MRI demonstrated a large, multiloculated cystic retroperitoneal mass causing displacement of the right kidney, ureter, and inferior vena cava. The patient underwent an exploratory laparotomy with complete excision, along with right hemicolectomy and ileocolic anastomosis. Histopathology confirmed moderately differentiated mucinous cystadenocarcinoma. Immunohistochemistry was suggestive of intestinal-type differentiation. Postoperative recovery was uneventful, and the patient was started on adjuvant chemotherapy. PRMC in males is rare and potentially aggressive. Complete surgical resection with negative margins remains the cornerstone of management, while adjuvant chemotherapy is considered in high-risk cases.