LAUSR

INTRODUCTION Primary retroperitoneal mucinous cystadenoma is an extremely uncommon tumor occurring mostly in females. The histogenesis of PRMC remains unclear and Open surgery is the most impressive treatment. CASE PRESENTATION We present a 20-year-old Iranian woman with history of intermittent abdominal pain. In physical examination, her abdomen had a mildly asymmetrical distention and a round shape mass was palpated in right abdomen also she had a mild tenderness in right abdomen. Radiologic assessment revealed a right retroperitoneal smooth cystic mass (20 × 15 cm) without invasive features. The patient underwent complete surgical excision of the tumor by a laparotomic approach because of its size. The lesion was gently dissected from the contiguous organs and removed completely without spillage of its content. In microscopic investigations, sections showed a unilocular cyst with fibrous wall lined via monolayered bland looking columnar mucinous epithelium and no atypia or stromal invasion was presented. Diagnosis of a PRMC was made. The patient has discharged without any complications in 2 days' postoperative course. DISCUSSION Generally, cysts are asymptomatic and are found fortuitously after a routine checkup assessment. Symptoms and signs related to this cyst are mainly because of their huge size and compression effect. Radiological assessments are effective in specifying the lesion preoperatively; although, the final diagnosis always needs histopathological verification. CONCLUSION When the tumor is diagnosed, full resection should be considered because of the infectious or malignant potential of the tumor.