LETTERS TO THE EDITOR

 

Lipoma of the pancreas: diagnosis and management of these rare tumors

Lipoma del pancreas: diagnóstico y tratamiento de estos raros tumores

 

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Palabras clave: Lipoma. Tumores benignos del páncreas. Páncreas.

Key words: Lipoma. Bening tumors of the pancreas. Pancreas.

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Dear Editor:

Nonductal pancreatic tumors are uncommon, accounting for 5% to 15% of all pancreatic neoplasms and include mesenchymal tumors which represent only 1% to 2% of all pancreatic neoplasms (1). Lipomas of the pancreas are bening mesenchymal tumors, are uncommun in this location (2). There are only sixteen published in the literature at the moment; most of them are diagnosed incidentally on CT scan or Ultrasonography (1-9).

We report the case of a patient with acute pancreatitis, and in the radiological studies we find incidentally a lipoma of the pancreas.

 

Case report

A 70-year-old woman presented epigastric pain, radiated to the left and right upper quadrant of the abdomen, vomits and hiperamilasemia. Physical examination was normal.

Abdominal Ultrasonography (US) showed a 3,8 x 2,7cms, round, solid, hypoechoic mass in the head of the pancreas; there was no biliary tract or pancreatic duct obstacle.

Computed Tomography (CT) demonstrated a 3 x 3 cms homogeneous, hipodense, polilobed mass, well circumscribed, and non-invasive, with a density of 100 HU which translate the fatty composition of the mass. There was no ductal dilatation and no biliary tract obstacle (Fig. 1).

In the Magnetic Resonance (MR) there was an ovoid, hiperintense, homogeneous, focal mass in the head of the pancreas, with a diameter of 3 x 3 cm. On standard T1-and T2- weighted images. The mass was isointense with the intraabdominal and subcutaneous fat on both T1-and T2 weighted images and was found to be homogeneously suppressed on frequency selected fat-suppression images. There was no contrast enhancement after the use of gadolinium-DTPA.

After the episode of acute pancreatitis the patient kept asymptomatic, without abnormal findings of liver function tests, so we decided not to do an histological confirmation because the CT diagnosis is very specific, and we made a conservative management. The evolution was good; in the US, 3, 6, 12 and 24 months later there were no changes.

 

Discussion

The lipomas of the pancreas are very rare. Only sixteen cases have been reported in the literature (1-9). Bigard, in 1989, described the first case (3) (Table I).

In our case the diagnosis was made with US, CT and MR; above all CT bring us the most exact radiological diagnosis and it has been proposed to be the method of choice for the detection of a fat containing lesions of the pancreas (4), the values ranging from 80 to 120 HU indicate a lesion composed of fat (2). CT can readily detect these lesions, like the other fat containing abnormalities of the pancreas and no further examinations are indicated (2, 4-7). MR imaging may be helpful in the differentiation between the fatty replacement of the pancreas, (which is one of the most common histological changes observed in the pancreas) and the lipoma of the pancreas (4), the two entities have similar densities (Hounsfield Units) but the difference is that the lipoma of the pancreas is an encapsulated, septated, fatty mass surrounded by pancreatic parenchyma, well circumscribed and non-invasive, and fatty replacement is more infiltrative and growth along fascial planes (1). Lipomas should be distinguished too from Liposarcoma, they are caracterized by higher densitometric values (HU) by greater size, by areas of solid or fluid densities, and by blurred outlines (1). Another entity is the Lipomatous pseudohypertrophy caracterized by enlarged pancreas with massive replacement of pancreatic exocrine tissue by adipose tissue (1). In conclu

sion, CT is an essential diagnosis tool in a case of intrapancreatic lipoma (2).

After the episode of acute pancreatitis our patient kept asymptomatic so the management was conservative (1-9). Only Raut et al. (1) approach into the management of symptomatic lipoma, they defend that may be treated with enucleation if the tumors are amenable and a Whipple procedure, distal pancreatectomy, or palliative by-pass surgery if the enucleation is not possible; the current low morbility and mortality rates associated with pancreatic resection justify this approach even with foreknowledge of the bening nature of this lesion.

 

Z. Salman Monte, M. Ruiz-Cabello Jiménez, P. Pardo Moreno¹and P. Montoro Martínez
Services of Digestive Diseases and ¹Radiology. Hospital Virgen de las Nieves. Granada

 

References

1. Bigard MA, Boissel P, Regent D, Froment N. Intrapancreatic lipoma: First case in the literature. Gastroenterol Clin Biol 1989; 13: 505-7.

2. DiMaggio EM, Solcia M, Dore R, Preda L, LaFianza A, Rodino C, et al. Intrapancreatic lipoma: First case diagnosed with CT. AJR 1996; 167: 56-7.

3. Itai Y, Saida Y, Kurosaki Y, Fijimoto T. Focal fatty mases of the pancreas. Acta Radiol 1995; 36: 178-81.

4. Katz DS, Nardi PM, Hines J, Barckhausen R, Math KR, Fruauff AA, et al. Lipomas of the pancreas. AJR 1998; 170: 1485-7.

5. Merli M, Fossati GS, Alessiani M, Spada M, Gambini D, Viezzoli A, et al. A rare case of pancreatic lipoma. Hepatogastroenterology 1996; 43: 734-6.

6. Boglio C, Inserra A, Silvano A, Ciprandi G, Boldrini R, Caione P. Intrapancreatic lipoma: A case report. Pediatr Med Chir 1993; 15: 397-9.

7. De Jong SA, Pickleman J, Rainsford K. Non-ductal tumors of the pancreas: the importance of laparotomy. Arch Surg 1993; 128: 730-6.

8. Raut CP, Fernández del-Castillo C. Giant lipoma of the pancreas: Case report and review of lipomatous lesions of the pancreas. Pancreas 2003; 26: 97-9.

9. Secil M, Igci E, Yigit A, Dicle O. Lipoma of the pancreas: MRI findings. Computerized Medical Imaging and Graphics 2001; 25: 507-9.