Peritoneal Lymphomatosis: The Great Mimicker.

Peritoneal lymphomatosis (PL) is defined as intraperitoneal dissemination of lymphoma. Although rare, it is associated with high-grade lymphomas and can be easily mistaken for peritoneal carcinomatosis (PC) on imaging, which is a common condition associated with gastrointestinal and gynecological malignancies. Both PL and PC share similar radiographic features, however, they differ considerably in terms of prognosis and management. We present a case of a 58-year-old male with abdominal distention and ascites, initially reported as having PC on imaging. A subsequent peritoneal biopsy revealed PL secondary to a low-grade follicular lymphoma. Since PL responds well to chemotherapy, its prompt diagnosis and differentiation from PC helps avoid unnecessary surgery.