Invasive Ductal Carcinoma Arising in Mucinous Cystic Neoplasm of Pancreas: A Case Report

Abstract

Patient: Female, 40 Final Diagnosis: Invasive ductal carcinoma arising in mucinous cystic neoplasm of pancreas Symptoms: None Medication: — Clinical Procedure: Surgical resection Specialty: Oncology Objective: Rare co-existance of disease or pathology Background: Mucinous cystic neoplasm (MCN) of the pancreas is a rare mucin-producing cystic neoplasm that has a characteristic histological feature referred to as ovarian-type stroma (OS) underlying the epithelium. Pancreatic ductal carcinoma arises from MCN as a precursor lesion, but data on progression pathways are limited. Case Report: A 40-year-old female was referred to our hospital for further investigation of a pancreatic cyst. Further examination showed a 7.0 cm multilocular cyst in the pancreatic tail and a solid mass in the thick septum of the cystic tumor. Distal pancreatectomy and splenectomy were performed. Histological examination revealed a moderately differentiated invasive ductal carcinoma (IDC) with a diameter of 0.5 cm in the thick septum of the cystic lesion and a cyst wall composed of epithelium with low-grade to severe dysplasia. The epithelium covered an OS. Pathological diagnosis was IDC arising in MCN of the pancreas. Immunohistochemical examination showed that MUC1 expression was negative in MCN but positive in IDC. KRAS mutation was observed in both MCN and IDC regions. Conclusions: We present a rare case of moderately differentiated pancreatic IDC arising in MCN. To elucidate the underlying progression pathway, we explored the correlation between KRAS mutation and MUC expression as a clinico-pathological parameter.

Update on mucinous cystic neoplasm of the pancreas: a narrative review

“…Thus, pattern of invasion is a strong prognostic histological parameter in MCN-AIC. This finding is supported by evidence from other studies: T1a and T1b invasive carcinomas arising from ovarian-type stroma, septa and cystic capsule have a long-term disease-free survival [9,31] . In our study the role of lymph node invasion could not be addressed due to the sample limitations.…”

“…This finding is supported by evidence from other studies: T1a and T1b invasive carcinomas arising from ovarian-type stroma, septa and cystic capsule have a long-term disease-free survival. [9,31] In our study the role of lymph node invasion could not be addressed due to the sample limitations. But another large retrospective study indicated that lymph node positivity is the most important factor for decreased survival of MCN-AIC, [32] a phenomenon also observed in a case report.…”

Pathologic T1 and T2 encapsulated invasive carcinomas arising from mucinous cystic neoplasms of the pancreas have favorable prognosis and might be treated conservatively

“…In the above‐mentioned studies, however, detailed information on the size of the invasive component or their pTNM classification was not given. More recently, two studies [ 4 , 20 ] provided evidence that T1a/T1b MCN‐AIC, which was limited to the ovarian‐type stroma, cystic septa, or hyalinized stroma in the superficial layer of the cyst wall, had excellent survival similar to noninvasive MCN. These four cases were all at relatively early stages of invasion with invasive foci measuring up to 0.7 cm…”

“…As for MCN‐AICs, Hui et al [ 4 ] presented three well‐documented T1a/T1b MCN‐AICs with favorable prognosis and advocated for regular follow‐up to reduce the use of systemic chemotherapy. A case report from Japan also showed a T1a MCN‐AIC patient who recovered without chemotherapy (the patient ceased chemotherapy after experiencing significant adverse reactions) [ 20 ]. All these four cases had invasion limited to ovarian‐type stroma, cyst septa, or the cyst capsule which might be identified as ‘encapsulated’ by our definition.…”

Mucinous cystic adenoma with inflammatory cell infiltration around the splenic artery mimicking pancreatic cancer: a case report

“…Ohtsuka et al reported on a long-term retrospective nationwide study of MCNs with OS and identified five factors predicting malignancy of MCNs: age 56 years or older, high serum CEA level, high CA19-9 level, tumor size ≥ 51 mm, and the presence of mural nodules [13]. However, Sawai et al reported a rare case of a moderately differentiated invasive ductal carcinoma measuring up to 0.5 cm in diameter in the superficial layer of the cyst wall in the OS [14]. Lewis et al found that invasive carcinoma confined to the OS of MCNs had an excellent prognosis [9].…”