Low grade appendiceal mucinous neoplasm mimicking malignant ovarian tumor: A case report

Abstract

Introduction: Mucinous appendiceal neoplasms are unique tumors in which >50 % of the tumor volume is composed of extracellular mucin. They may present as an unruptured mucin-filled appendix or, more commonly, with peritoneal metastases after rupture or transmural invasion of the primary tumor. This case report describes a case of presumed ovarian malignancy with final pathologic diagnosis of low grade appendiceal mucinous neoplasm. Due to its rarity, we decided to report it.

Case presentation: A 37-year-old patient presented with a compliant of abdominal swelling. Abdominopelvic ultrasound was done and showed huge right and left complex cystic ovarian masses having thick septa. For this, she underwent total abdominal hysterectomy, omentectomy and bilateral salpingo-oophorectomy. On laparotomy there was also incidental finding of ruptured mucin-filled appendix for which appendectomy was done. Histopathology examinations from all resected specimens revealed the diagnosed LAMN. Two weeks after surgical resection, she was started on FOLFOX chemotherapy regimen.

Discussion: Incidence of low grade appendiceal mucinous neoplasm is increasing. In addition to the increasing incidence, lack of early detection and impeded access to optimal multi-disciplinary treatment may worsen survival outcomes. Developing quality diagnostic services in the proper health context is crucial for early diagnosis and successful therapy of LAMN patients, and applying a resource-sensitive approach to prioritize essential treatments based on effectiveness and cost-effectiveness is key to overcoming barriers in low- and middle-income countries.

Conclusion: A recognition of mucinous material and abnormal appearing appendix should prompt the surgeon to consider performing an appendectomy to obtain primary pathologic diagnosis.

Keywords: Case report; Low grade appendiceal mucinous neoplasm; Low- and middle-income countries; Ovarian cancer; Pseudomyxoma peritonei.

Fig. 1

20x10x10 cm complex cystic right ovarian mass with smooth outer surface.

Fig. 2

Total abdominal hysterectomy specimen (horizontal arrow) and 10x10x7cm complex cystic left ovarian mass with smooth outer surface (vertical arrow).

Fig. 3

Omentectomy specimen showing numerous glistening nodularities.

Fig. 4

Appendectomy specimen with a ruptured focus.

Fig. 5

Cut surface examination of both ovarian masses showed multilocular cystic spaces filled with jelly like material.

Fig. 6

Low power (10X) microscopic examination of complex cystic ovarian masses showing abundant mucin characteristically exhibiting expansile growth with a pushing border (Hematoxylin and Eosin stain).

Fig. 7

High power (40X) microscopic examination of complex cystic ovarian masses showing abundant mucin characteristically exhibiting expansile growth with a pushing border (Hematoxylin and Eosin stain).

Fig. 8

High power (40X) microscopic examination of appendectomy specimen showing abundant mucin characteristically exhibiting expansile growth with a pushing border (Hematoxylin and Eosin stain).

Fig. 9

High power (40X) microscopic examination of omentectomy specimen showing abundant mucin characteristically exhibiting expansile growth with a pushing border (Hematoxylin and Eosin stain).

Fig. 10

Algorithm for management of LAMN. *No consensus for ruptured LAMN with malignant cells in right lower quadrant – most takes a conservative approach.