Rare Solid Pancreatic Lesions on Cross-Sectional Imaging

Abstract

Several solid lesions can be found within the pancreas mainly arising from the exocrine and endocrine pancreatic tissue. Among all pancreatic malignancies, the most common subtype is pancreatic ductal adenocarcinoma (PDAC), to a point that pancreatic cancer and PDAC are used interchangeably. But, in addition to PDAC, and to the other most common and well-known solid lesions, either related to benign conditions, such as pancreatitis, or not so benign, such as pancreatic neuroendocrine neoplasms (pNENs), there are solid pancreatic lesions considered rare due to their low incidence. These lesions may originate from a cell line with a differentiation other than exocrine/endocrine, such as from the nerve sheath as for pancreatic schwannoma or from mesenchymal cells as for solitary fibrous tumour. These rare solid pancreatic lesions may show a behaviour that ranges in a benign to highly aggressive malignant spectrum. This review includes cases of an intrapancreatic accessory spleen, pancreatic tuberculosis, solid serous cystadenoma, solid pseudopapillary tumour, pancreatic schwannoma, purely intraductal neuroendocrine tumour, pancreatic fibrous solitary tumour, acinar cell carcinoma, undifferentiated carcinoma with osteoclastic-like giant cells, adenosquamous carcinoma, colloid carcinoma of the pancreas, primary leiomyosarcoma of the pancreas, primary and secondary pancreatic lymphoma and metastases within the pancreas. Therefore, it is important to determine the correct diagnosis to ensure optimal patient management. Because of their rarity, their existence is less well known and, when depicted, in most cases incidentally, the correct diagnosis remains challenging. However, there are some typical imaging features present on cross-sectional imaging modalities that, taken into account with the clinical and biological context, contribute substantially to achieve the correct diagnosis.

An Unusual Cause of Pancreatic Tumor

“…Among extrapulmonary sites, TB affecting the gastrointestinal tract is the sixth most common, with abdominal TB accounting for approximately 10% of cases [ 5 , 6 ]. Isolated pancreatic TB is very rare, even in endemic areas.…”

Comprehensive review of pancreatic acinar cell carcinoma: epidemiology, diagnosis, molecular features and treatment

“…SPN is more common in young and middle-aged women and is frequently located in the tail of the pancreas ( 41–44 ). Calcification is also a prominent characteristic of SPN ( 45 ). Recently, it was reported that PACC and SPN can be differentiated based on imaging findings (tumour location, maximum diameter, boundary, intratumoral vessels and distant metastasis) ( 42 ).…”

“…Some cases of pNEN show a similar histologic architecture, although necrosis is uncommon ( 46 ). The appearance of pNEN on CT is very variable and includes heterogeneous density with haemorrhage, cystic changes, necrosis and calcification ( 45 , 47 ). In children, PACC needs to be distinguished from pancreatoblastoma, a rare type of malignant pancreatic tumour that arises from the exocrine cells of the pancreas and is rare in adults ( 15 , 16 , 48–50 ).…”