Microscopic description and IHC:

There are microscopically identifiable cysts with occasional partially lined ductal epithelium. The cysts can also contain eosinophilic, amorphous secretions and can have markedly inflamed pericystic fibrous tissue. A reactive spindle cell proliferation, Brunner’s gland hyperplasia, and calcifications can also be seen.

Discussion:

Groove pancreatitis is a rare type of chronic pancreatitis, primarily affecting the head of the pancreas. This lesion is classically described in middle-aged men and pathonomic for chronic alcohol use. The clinician should be alerted if seen as the patient may not divulge history alcohol use/abuse which may un-expectantly lead to delirium tremors. It can also be seen in smokers and women, but to a lesser degree. It can present clinically with weight loss, abdominal pain, nausea, and vomiting; weight loss and heavy alcohol use are most correlated with this lesion. On imagining it is described as a cystic-like pancreatic mass with duodenal wall thickening, which is concerning for a pancreatic cystic or solid neoplasm. Additional nomenclature includes: para-ampullary duodenal wall cyst, paraduodenal pancreatitis, cystic dystrophy of the duodenal wall, heteroptic pancreas, pancreatic hamartoma of the duodenum, paraduodenal wall cyst, and myodenomatosis.

References:

Oza, Veeral M VM (08/2015). "Groove Pancreatitis, a Masquerading Yet Distinct Clinicopathological Entity: Analysis of Risk Factors and Differentiation.". Pancreas (0885-3177), 44 (6), p. 901. PMID:25899649

Hruban, R., Pitman, M. & Klimstra, D. (2007). Tumors of the pancreas. Washington, D.C: American Registry of Pathology in collaboration with the Armed Forces Institute of Pathology. p. 356-358

Pallisera-Lloveras, Anna A (05/2015). "Groove pancreatitis.". Revista española de enfermedades digestivas (1130-0108), 107 (5), p. 280. PMID:25952803

CASE IMAGES