Pseudomyxoma peritonei originating from intestinal duplication: A case report and review of the literature

Abstract

Background: Pseudomyxoma peritonei (PMP) is a rare mucinous neoplasm with a relatively low incidence of 1 to 2 per million individuals. It is typically characterized by a type of gelatinous ascites named "jelly belly". Most cases of PMP occur in association with ruptured primary mucinous tumors of the appendix (90%). Periodically, PMP can originate from mucinous carcinomas at other sites, including the colorectum, gallbladder, and pancreas. However, unusual origin can occur, as noted in this case report.

Case summary: A 52-year-old woman had an unusual derivation of PMP from intestinal duplication. The patient complained of abdominal distension and increasing abdominal girth. Abdominal contrast-enhanced computed tomography showed a mass in the greater omentum located on the left side of the abdomen, likely to be a cystic mass of peritoneal origin. A PMP diagnosis was presumed based on the specific signs of the mass with flocculent and stripe-like echoes in ultrasound images. Ultrasound-guided percutaneous aspiration suggested a high likelihood of PMP. Once the PMP diagnosis was recognized, identification of the origin of the primary tumor was indicated. Thus, an exploratory laparoscopy was performed. In the absence of a primary tumor of appendix origin, the diagnosis of a low-grade mucinous neoplasm of intestinal duplication origin was finally confirmed by histopathology.

Conclusion: PMP is secondary to mucinous carcinomas of the appendix mostly. This case resulted from an unusual derivation from intestinal duplication.

Keywords: Case report; Diagnosis; Intestinal duplication; Mucinous ascites; Mucinous tumor; Pseudomyxoma peritonei.

Figure 1

Abdominal contrast-enhanced computed tomography revealed a low density mass in the upper abdomen proximal to the spleen (arrow).

Figure 2

Ultrasound image and transabdominal ultrasound-guided percutaneous aspiration of the mass in the left upper abdomen. A: A large mass with flocculent and stripe-like echoes (arrow) was detected in the left middle and upper abdomen by ultrasound; B: Yellow gelatinous material was aspirated from the abdomen via transabdominal ultrasound-guided percutaneous aspiration.

Figure 3

The obtained appendix specimen and its hematoxylin-eosin staining results. A: Gross pathology of appendix showed a length of 5.0 cm and width of 0.3-0.6 cm in diameter; B: Hematoxylin-eosin staining results of the specimen demonstrated appendicitis obliterans.

Figure 4

Intraoperative pictures. A: Characteristic cystic mass (arrow) presented in the anterior lobe of the transverse mesocolon in the left part of the splenic flexure; B: A yellow jelly-like mass existed inside.

Figure 5

Hematoxylin-eosin staining of the specimen found in the splenic flexure of the colon revealed a cystic mass emanating from the intestinal duplication, with low-grade mucinous epithelial cells lining in the capsule wall. A: × 40; B: × 200.

Figure 6

Histologic presentation of low-grade mucinous neoplasm. A: Hematoxylin-eosin staining of the primary tumor; B-F: Immunohistochemical staining found that the primary tumor was CK-7(–) (B), CK-20(+) (C), Villin(+) (D), CDX-2(+) (E), and MUC-2(+) (F).