Mucinous Cystic Neoplasms in Male Patients: Histopathological and Molecular Diagnoses

Abstract

Cystic mucinous neoplasms (MCNs) of the pancreas are rare cystic tumors, accounting for approximately 2-5% of all pancreatic neoplasms. They predominantly occur in premenopausal women and are typically located in the body or tail of the pancreas. Due to their potential for malignant transformation, especially in cases associated with invasive carcinoma such as pancreatic ductal adenocarcinoma, early detection, complete surgical resection, and rigorous postoperative surveillance are essential. The occurrence of MCNs in male patients is exceedingly rare, comprising only about 2% of reported cases, and often resulting in preoperative diagnostic challenges. Molecular analyses have identified a strong association between KRAS mutations and disease progression in MCNs, underscoring their potential role as prognostic markers despite limited diagnostic utility. In this report, we present two additional cases of MCNs in male patients, highlighting their histopathological features and the ancillary investigations undertaken to support diagnosis.

Keywords: KRAS; case report; cystic mucinous neoplasms; cystic tumors; male; pancreas.

Figure 1

Multiplanar reconstructions in coronal (a) and axial (b–d) views of a neoplasm in the head of the pancreas (arrow) of approximately 30 mm in size, dislocating the stomach, spleen, and left adrenal gland and causing compression of the splenic vein (with congestion of the perigastric vessels) and thrombosis of the renal vein.

Figure 1

Multiplanar reconstructions in coronal (a) and axial (b–d) views of a neoplasm in the head of the pancreas (arrow) of approximately 30 mm in size, dislocating the stomach, spleen, and left adrenal gland and causing compression of the splenic vein (with congestion of the perigastric vessels) and thrombosis of the renal vein.

Figure 2

Macroscopic, microscopic and immunohistochemical analysis. (a) Specimen examination showing a cystic mass measuring 25 × 16 × 17 mm with round borders displacing the spleen. (b) At the microscopic examination, the cystic wall was partly de-epithelialized with stromal inflammation and pigment deposits, partly covered by a monolayered cuboidal eosinophilic or columnar mucinous epithelium, and focally squamous metaplasia. (c) The epithelial component showed pseudopapillary, papillary, and cribriform architectural patterns as well as areas of cytological high-grade dysplasia. (d) In only one of the ninety-three inclusions, a small focus of tubular adenocarcinoma limited to the cystic wall was evidenced. (e) The surrounding stroma was widely fibrohyaline except for some subepithelial highly hypercellulated areas strongly positive for estrogen receptors (anti-Estrogen Receptor Ventana Roche) (f) and progesterone receptors (anti-Progesterone Receptor Ventana Roche).

Figure 3

Multiplanar reconstructions in axial views of a cystic lesion of the tail of the pancreas of about 30 mm (a,b) with slight post-contrast enhancement of the walls in an MRI (c).

Figure 4

Histological and immunohistochemical analysis. (a) At the microscopic examination, the cystic lesion showed a simple columnar and cuboidal mucinous epithelium. (b) Ovarian stroma (anti-Estrogen Receptor Ventana Roche × 200). (c) Ovarian stroma (anti-Progesterone Receptor Ventana Roche × 100).