Vanishing Pancreas

Abstract

Question: An 88-year-old woman was referred for evaluation of mild iron deficiency anemia. The patient did not smoke or drink. She had no symptoms and no history of diabetes mellitus. Physical examination was unremarkable. Laboratory tests were significant for the following: hemoglobin, 9.2 g/dL; amylase, 9 U/L; and lipase, 6 U/L. Esophagogastroduodenoscopy revealed a gastric antrum adenocarcinoma. An abdominal computed tomography (CT) scan with contrast material showed lucent area where pancreas should be (Figure A, B). What is the most likely diagnosis based on the abdominal CT scan? Look on page 281 for the answer and see the Gastroenterology website (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. Abdominal CT scan with contrast material revealed that the entire pancreatic parenchyma was absent, leaving only a contrast-enhancing net-like shadow. T1-weighted magnetic resonance imaging with gadolinium enhancement and fat suppression (Figure C) revealed the absence of the entire pancreatic parenchyma; diffuse enlargement and fat replacement were present over the entire pancreas. Magnetic resonance cholangiopancreatography revealed no abnormalities in the pancreaticobiliary ducts or ductal anomaly. The patient underwent a laparoscopy-assisted distal gastrectomy for gastric antrum adenocarcinoma. Macroscopically, the pancreas was yellowish, soft, and massively enlarged (Figure D). At the time of laparoscopy, needle biopsy of the pancreas was performed (Figure E). Histologic examination revealed that mature adipose tissue was seen in the fibrous connective tissue, but no pancreatic parenchyma was identified (Figure F). There was no evidence of a neoplasm of the pancreas. On the basis of these findings, the diagnosis of lipomatous pseudohypertrophy of the pancreas was made. The vanishing pancreas is a sobriquet for lipomatous replacement of the gland.1Bartholomew L.G. Baggenstross A.H. Morlock C.G. et al.Primary atrophy and lipomatosis of the pancreas.Gastroenterology. 1959; 36: 563-572Abstract Full Text PDF PubMed Scopus (13) Google Scholar The replacement of the entire pancreas with increasing amounts of adipose tissue and the consequent enlargement of the pancreas was first described by Hantelmann in 1933. This disease was later named lipomatous pseudohypertrophy of the pancreas.2Yasuda M. Niina Y. Uchida M. et al.A case of lipomatous pseudohypertrophy of the pancreas diagnosed by typical imaging.JOP. 2010; 11: 385-388PubMed Google Scholar Lipomatous pseudohypertrophy of the pancreas is an extremely rare idiopathic entity that is characterized by the replacement of acinar cells with mature adipose tissue, although the pancreatic duct and islets of Langerhans are preserved.2Yasuda M. Niina Y. Uchida M. et al.A case of lipomatous pseudohypertrophy of the pancreas diagnosed by typical imaging.JOP. 2010; 11: 385-388PubMed Google Scholar, 3Altinel D. Basturk O. Sarmiento J.M. et al.Lipomatous pseudohypertrophy of the pancreas: a clinicopathologically distinct entity.Pancreas. 2010; 39: 392-397Crossref PubMed Scopus (33) Google Scholar It may present as exocrine deficiency symptoms or be incidentally identified during an examination for other conditions, as seen in this case. To make a definitive diagnosis of lipomatous pseudohypertrophy of the pancreas, this condition must be distinguishable from obesity, diabetes, and age-related pancreatic fat infiltration and liposarcoma.2Yasuda M. Niina Y. Uchida M. et al.A case of lipomatous pseudohypertrophy of the pancreas diagnosed by typical imaging.JOP. 2010; 11: 385-388PubMed Google Scholar It often forms a mass that mimics pancreatic cancer and may result in unnecessary resection and morbidity.3Altinel D. Basturk O. Sarmiento J.M. et al.Lipomatous pseudohypertrophy of the pancreas: a clinicopathologically distinct entity.Pancreas. 2010; 39: 392-397Crossref PubMed Scopus (33) Google Scholar Lipomatous pseudohypertrophy of the pancreas is diagnosed by histologic findings obtained via resected specimens or endoscopic ultrasound-guided fine-needle aspiration; however, the diagnosis may be made based on typical imaging findings and serologic data showing pancreatic enzyme deficiency.2Yasuda M. Niina Y. Uchida M. et al.A case of lipomatous pseudohypertrophy of the pancreas diagnosed by typical imaging.JOP. 2010; 11: 385-388PubMed Google Scholar Because lipomatous pseudohypertrophy of the pancreas is a benign disease, conservative management is thought to be sufficient.2Yasuda M. Niina Y. Uchida M. et al.A case of lipomatous pseudohypertrophy of the pancreas diagnosed by typical imaging.JOP. 2010; 11: 385-388PubMed Google Scholar Awareness of this condition helps to prevent inappropriate treatment.