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PSEUDOMYXOMA PERITONEI DUE TO LOW-GRADE APPENDICEAL MUCINOUS NEOPLASM: A CASE REPORT
Arillany da Silva Mendes Cortes
2, Leticia S. Pacheco
*4, Carolina V. Tambasco
3, Luiza M. Assumpção
3, Sergio Fischbach
1, Andreas Koszka
1, Carlos A. Pantanali
1,5, Alberto Meyer
11Sociedade Beneficente Israelita Brasileira Albert Einstein, Sao Paulo, São Paulo, Brazil; 2Faculdade das Americas, Sao Paulo, SP, Brazil; 3Universidade de Santo Amaro Faculdade de Medicina, Sao Paulo, São Paulo, Brazil; 4Pontificia Universidade Catolica de Sao Paulo Faculdade de Ciencias Medicas e da Saude, Sorocaba, São Paulo, Brazil; 5Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, São Paulo, Brazil
Introduction:Pseudomyxoma peritonei (PMP) is a rare clinical entity characterized by the accumulation of mucinous ascites, most commonly arising secondary to low-grade appendiceal mucinous neoplasms (LAMNs). This report describes a case of PMP due to LAMN, diagnosed incidentally following laparoscopic appendectomy and successfully treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).
Case Presentation:A 37-year-old male presented with a 6-day history of severe right iliac fossa pain, progressive abdominal distension, diarrhea, night sweats, and febrile episodes (38°C). His past medical history was notable for chronic hepatitis B under treatment with pegylated interferon alfa-2a. On clinical examination, localized tenderness in the right iliac fossa with rebound tenderness and guarding suggested peritonitis. Laboratory tests revealed microcytic anemia.
Contrast-enhanced computed tomography (CT) demonstrated perforated appendicitis localized to the distal tip of the appendix, associated with a contained 15cc fluid collection in the right iliac fossa (Figure 1). Emergency laparoscopic appendectomy was performed, during which the peritoneal abscess was drained, the inflamed cecal appendix was resected, and a Penrose drain was inserted. The postoperative course was uneventful, and the patient was discharged on postoperative day 6 after two days of bowel rest.
Histopathological analysis of the resected appendix revealed a low-grade appendiceal mucinous neoplasm (LAMN), with mucin extrusion confined to the appendiceal wall and no evidence of extra-appendiceal dissemination. Serum tumor markers, including CEA, CA 19-9, and CA-125, were within normal limits.
Subsequent abdominal magnetic resonance imaging (MRI) identified nodular implants within the anterior peritoneal fat of the left hypochondrium and bilateral flanks, consistent with low-volume peritoneal metastases (Figure 2). In view of the findings, the patient was referred for definitive treatment. One month later, he underwent complete cytoreductive surgery (CRS), including peritonectomy and removal of visible peritoneal implants, followed by HIPEC using cisplatin at a perfusion temperature of 42°C.
Postoperatively, the patient demonstrated an uncomplicated recovery, resuming oral intake on postoperative day 3 and being discharged on postoperative day 7. Final histopathological examination of the resected specimens confirmed the absence of residual neoplastic disease.
Conclusion:This case illustrates a rare presentation of PMP secondary to perforated LAMN, successfully managed with CRS and HIPEC. LAMN poses a significant risk of peritoneal dissemination if not identified and treated promptly. Thus, early histopathological diagnosis, comprehensive preoperative imaging, and aggressive surgical intervention remain the cornerstone of PMP management.
Perforated appendicitis localized to the distal tip of the appendix, associated with a 15cc fluid collection blocked by the terminal ileum.
Nodular implants in the anterior peritoneal fat of the left hypochondrium and flank, consistent with low-volume peritoneal metastases.
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