Concomitance of intraductal papillary mucinous neoplasm with pancreatic stones: indication for immediate surgery

Excerpt

IPMN can remain asymptomatic for a long time, even if the mucinous secretion accumulates in the pancreatic ducts and causes obstacle to the outflow of the pancreatic juice and dilation of the main pancreatic duct (MD). Typically, acute pancreatitis attacks can happen in these eventualities. More rare is the occurrence of stones in the pancreatic ducts with concomitant atrophy of the exocrine pancreatic component. The discovering of pancreatic stones in diagnostic tests may imply to establish a differential diagnosis with chronic pancreatitis. Our recent observation of IPMN associated with pancreatic stones prompted us to revisit the updated evidences and to consider if this clinical condition is an indication for a prompt surgery. A 74-year-old female patient consulted the GP doctor for recurrent moderate back pain in January 2021. She was a heavy smoker (20–30 cigarettes a day) for more than 50 years with no alcohol consumption. Abdominal ultrasound showed dilation of the MD up to 7 mm with inside a 15 mm stone and 3 cm hypoechoic oval formation in the pancreatic head. Serum CEA and CA19-9 were within the normal limits. Two months later, CT scan confirmed ectasia of the pancreatic duct along its entire course, multiple pancreatic calcifications of the body and tail of the pancreas, and formation of multiloculated cystic aspect of the maximum size of 5 cm at the level of the pancreatic head (Fig.  1). The same cystic pancreatic alteration and dilation of the MD were confirmed by MRI and by EUS. Based on the imaging exams, our final diagnosis was the simultaneous presence of MD/side branch IPMN and chronic calcifying pancreatitis. Given the symptoms, the progressive increase in volume of the cyst, and the dilation of the MD, the probability of malignancy was evaluated high and surgery was decided. Preserving pylorus duodeno-pancreatectomy was performed. At surgery, the pancreatic head was entirely substituted by a large cystic lesion that did not infiltrate the surrounding structures. Sectioning the pancreas at the level of the isthmus, some whitish stones were present inside the duct. A Randall forceps was used to probe the duct which appeared straight and to extract the stones. The frozen section of the pancreatic stump did not show dysplastic or neoplastic changes. The pancreatic reconstruction was done by wirsung-jejunostomy. The postoperative course was regular and the patient was discharged on the 9th postoperative day. The examination of the surgical specimen revealed mucinous cystic neoplasia in the head of the pancreas, measuring 4.7 cm in diameter. In some places, the epithelium became papillary and the cells showed aspects of high-grade dysplasia. The proliferation index assessed with Ki67 was low (< 2%). No areas of infiltrating carcinoma are identified. The coexistence of IPMN and pancreatic stones is considered a rare circumstance. However, pancreatic calcification is not unusual when accurate revision of the preoperative CT was made. At Mayo Clinic, Zapiach et al. found pancreatic calcification in 10 of more than 40 patients treated for IPMN [ 1]. Recently, calcification were found, respectively, in 33 of 164 (20%) and in 27 of 157 (17.2%) resected IPMNs [ 2, 3]. Different types of calcification are possible: punctate (< 5 mm), coarse (> 5 mm), or eggshell. About half of the cases have coarse calcification. A significative relationship between pancreatic calcification and invasive intraductal papillary mucinous carcinoma was found, especially when coarse calcifications are present [ 2, 3]. The process of calcification of pancreatic secretion inside the ducts seems very slow [ 4]. Therefore, when pancreatic stones are detected, IPMN is lasting from a long time and neoplastic progression is more probable. The decision to operate IPMNs must be based on the assessment of the malignant risk. Currently, the definitive diagnosis of malignancy remains challenging having a low reliability either the imaging, the analysis of the pancreatic cyst fluid for cytology and markers’ assay, or the biopsy. Several international guidelines were proposed evaluating the symptoms and the imaging features for the clinical decision-making. Two risk classes have been defined: “high risk stigmata” (“HRS”) and “worrisome features” (“WF”). When “HRS” are present, surgical resection is recommended; meanwhile, when “WF” are identified, surveillance with endoscopic ultrasound is preferred [ 5]. In the analysis of Tsuijame et al., the specificity of pancreatic calcification for the diagnosis of invasive cancer is particularly high (88.9%) and superior to that exhibited only by “HRS” (57.4%) [ 3]. Therefore, in light of this and seeing our experience, it could be concluded that surgery should be recommended when IPMN is associated with coarse pancreatic calcification.

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