Pseudo-Carcinomatosis – an Atypical Presentation of Pseudomyxoma Peritonei in a Morbidly Obese Patient

Abstract

Purpose: Introduction: Pseudomyxoma peritonei is a rare clinical entity typically diagnosed on clinical presentation with increased abdominal girth, abdominal mass, or abdominal pain mimicking acute appendicitis. We present a morbidly obese male with vague gastrointestinal complaints and right upper quadrant fullness who was found to have carcinomatosis on computed tomography. Multiple fine needle aspirations failed to yield a diagnosis. Laparotomy was performed and revealed pseudomyxoma peritonei. Case: A 55 year old, morbidly obese Caucasian man presented with a six month history of intermittent diarrhea, occasional nausea and vomiting, and dyspeptic symptoms. He reported a family history of pancreatic malignancy. On physical examination, the patient was a large male (BMI 43) with right upper quadrant fullness, however no distinct mass was appreciated. Computed tomography of the abdomen and pelvis revealed ascites and marked infiltration of the omentum, suggestive of carcinomatosis. Upper endoscopy and colonoscopy were normal. Tumor markers including CA 19-9, CEA, and alpha-fetoprotein were also within normal limits. Fine needle aspiration of the peritoneum revealed fibroadipose tissue and cytopathology of the ascites was negative for malignant cells. Repeat aspiration yielded similar results. A diagnostic laparoscopy with omental biopsy revealed mucin, with rare clusters of well-differentiated adenocarcinoma, consistent with a diagnosis of pseudomyxoma peritonei. Discussion: Pseudomyxoma peritonei is manifested by diffuse gelatinous implantation of the peritoneal cavity and omentum most commonly from an appendiceal mucinous neoplasm. The diagnosis is often challenging in part due to its non-specific symptoms at presentation. Classic radiographic findings include scalloping of organs, ascitic septations and curvilinear calcifications. Our patient had vague gastrointestinal complaints and radiographic findings consistent with carcinomatosis. “Pseudocarcinomatosis” has been described in association with peritoneal fascioliasis, coccidioidomycosis and intraperitoneal endometriosis. Our case illustrates the importance of considering pseudomyxoma peritonei in the differential diagnosis of patients presenting with radiographic findings consistent with carcinomatosis, especially when no primary malignancy can be identified and repeat cytology is negative. Methods: N/A Results: N/A Conclusion: N/A