Benign Tumors and Tumorlike Lesions of the Pancreas

Abstract

Synopsis The pancreas is a complex organ that may give rise to large number of neoplasms and non-neoplastic lesions. This article will focus on benign neoplasms such as serous neoplasms as well as tumor-like (pseudotumoral) lesions that may be mistaken for neoplasm not only by clinicians and radiologists, but also by pathologists. The family of pancreatic pseudotumors, by a loosely defined conception of that term, includes a variety of lesions including heterotopia, hamartoma, and lipomatous pseudohypertrophy. Autoimmue pancreatitis (covered in chronic pancreatitis chapter) and paraduodenal (“groove”) pancreatitis may also lead to pseudotumor formation. Knowledge of these entities will help in making an accurate diagnosis.

Inflammatory and tumor-like lesions of the pancreas

“…The vast majority of patients with PGP are middle-aged men (5 th decade) with a history of alcohol abuse and smoking 26 . The clinical syndrome includes an important symptomatology with severe waxing and waning upper abdominal pain, disordered gastric emptying, postprandial vomiting and weight loss due to duodenal stenosis 2 , 26 , 27 . Although its pathogenesis remains not completely understood, the main hypothesis attributes the onset of this disease to a chronic obstruction of the minor papilla 24 .…”

“…Imaging reveals thickening of the duodenal wall with associated cyst formation within the duodenum or the groove area, with a consequent radiographic appearance of a pseudocyst or of a cystic pancreatic neoplasm 2 . More rarely, cases with minor cystic changes or solid lesions, often related to the sclerotic changes in the periampullary region, may mimic a pancreatic or a periampullary malignancy 27-30 . The therapeutic strategies for PGP may be supportive/conservative but, in case of a severe and longstanding symptomatology, and/or also in case of a difficult differential diagnosis with cancer, the first choice is represented by pancreaticoduodenectomy 26-30 .…”

“…On cut sections, the epicenter of PGP can be identified around the minor papilla, with variable involvement of the groove area, which can be relatively gelatinous to solid, or contain cysts. In some cases, cyst formation may be prominent, measuring up to several centimeters in size, mimicking intestinal duplication 27 . The cysts are filled with proteinaceous debris, usually have a smooth, opaque wall and may contain small calculi 2 .…”

“…Disperse in this fibrotic background, there are fibroblasts, myofibroblasts and smooth muscle cells. In the duodenal wall, a marked, bulging Brunner gland hyperplasia is often present, contributing to the thickening of the intestinal wall 2 , 24 , 27 , 31 . The cysts can be either restricted to the submucosal and muscular layers of the duodenal wall, or extended to the groove region.…”

“…The cysts contain small calculi that may extravasate causing a foreign body giant cells reaction 2 , which may call for a differential diagnosis with undifferentiated carcinoma of the pancreas with osteoclast-like giant cells 30 . In late stage of disease, the proper pancreas usually shows atrophy, fat necrosis, chronic inflammation and thick fibrosis 2 , 27 . Prominence of nerve bundles resembling traumatic neuroma is also a common finding in such area 27 .…”