A systematic review of pancreatic lipoma: how come there are so few cases?

Pancreatic ductal adenocarcinoma arising from the pancreatic parenchyma compressed by a huge pancreatic lipoma: a case report

BACKGROUND

Pancreatic lipomas (PLs) arising from the adipose tissue in the pancreatic parenchyma are rare among pancreatic tumors. Coexisting pancreatic ductal adenocarcinoma (PDAC) and PLs have not been previously reported. Herein, we report a case of PDAC arising from the pancreatic parenchyma with chronic pancreatitis compressed by a large PL.

CASE PRESENTATION

The patient was a 69-year-old male. He had been diagnosed with a PL using computed tomography (CT) 12 years previously. The tumor had been slowly growing and was followed up carefully because of the possibility of well-differentiated liposarcoma. During follow-up, laboratory data revealed liver damage and slightly elevated levels of inflammatory markers. Contrast-enhanced CT revealed the previously diagnosed 12 cm pancreatic head tumor and an irregular isodensity mass at the upper margin of the tumor that invaded and obstructed the distal common bile duct. Magnetic resonance cholangiopancreatography demonstrated no specific findings in the main pancreatic duct. Based on these imaging findings, the patient underwent endoscopic retrograde biliary drainage and bile duct brushing cytology, which revealed indeterminate findings. The differential diagnosis of the tumor at that time was as follows: (1) pancreatic liposarcoma (focal change from well-differentiated to dedifferentiated, not lipoma), (2) distal cholangiocarcinoma, and (3) pancreatic cancer. After the cholangitis improved, a pancreatoduodenectomy was performed. Histologically, hematoxylin-eosin staining revealed moderately differentiated PDAC compressed by proliferating adipose tissue. The adipose lesion showed homogeneous adipose tissue with no evidence of sarcoma, which led to a diagnosis of lipoma. Additionally, extensive fibrosis of the pancreatic parenchyma and atrophy of the acinar cells around the lipoma was suggestive of chronic pancreatitis. The pathological diagnosis was PDAC (pT2N0M0 pStage Ib) with chronic pancreatitis and PL. The postoperative course was uneventful, and the patient was discharged on the 15th day after surgery. The patient received adjuvant chemotherapy and has remained recurrence-free for more than 6 months.

CONCLUSIONS

PL may be associated with the development of PDAC in the surrounding inflammatory microenvironment of chronic pancreatitis. In cases of growing lipomas, careful radiologic surveillance may be needed not only for the possibility of liposarcoma but also for the coincidental occurrence of PDAC.

A huge pancreatic lipoma mimicking a well-differentiated liposarcoma: A case report and systematic literature review

BACKGROUND

Pancreatic lipomas are thought to be very rare. Lipomas are usually easy to identify on imaging, particularly via computed tomography (CT). But sometimes it’s quite difficult to distinguish a lipoma from a well-liposarcoma without histologic result.

CASE SUMMARY

Here, we present a case of pancreatic lipoma in a 59-year-old female. She was asymptomatic and had no medical history of note. CT and magnetic resonance imaging revealed a mass like well-differentiated liposarcoma in the pancreatic head, positron emission tomography/CT showed a low fluorodeoxyglucose uptake and laboratory tests revealed elevated transaminase and carbohydrate antigen-199 levels. Finally, the patient underwent a pancreaticoduodenectomy. Histologically, mature adipocytes were noted in the bulk of the tumor. Accordingly, the pathologic diagnosis of the pancreatic neoplasm was lipoma. To our knowledge, this case is the first example of a suspected well-differentiated liposarcoma that was actually a pancreatic lipoma. We also highlight the radiological features distinguishing a pancreatic lipoma from a pancreatic liposarcoma and briefly review the literature.

CONCLUSION

Pancreatic lipomas show no obvious gender bias and most commonly occur in the head of the pancreas, of which the maximum diameters are often less than 5 cm, and small, asymptomatic non-compressed lipomas require follow-up only. Surgical excision should be considered when the tumor has compressed important tissues or is difficult to distinguish from a liposarcoma, the choice of surgery depends on the intraoperative presentation.

Pancreatic lipoma with a solid nodule mimicking invasion from adjoining intraductal papillary mucinous neoplasm

A 74-year-old man was referred to our hospital for a mass in the pancreatic head found during screening chest computed tomography. Contrast computed tomography showed a 5-cm multicystic mass with an irregular border containing a solid component showing contrast enhancement. Caudal to this mass, a 5-cm solid mass of fat density with a nodular soft-tissue component was found. Cytology of the aspirated pancreatic fluid revealed malignant cells, and surgery was performed for suspected intraductal papillary mucinous carcinoma. Pathologic analysis of the resected specimen revealed a collision tumor of intraductal papillary mucinous neoplasm (IPMN) with high-grade dysplasia and pancreatic lipoma. The soft-tissue component within the lipoma was a nodule consisting of pancreatic tissue with inflammatory infiltration and hyalinization and was not associated with IPMN invasion.

The natural history of pancreatic lipoma: Does it need observation

BACKGROUND

Pancreatic lipomas (PL) are a rare, benign mesenchymal neoplasm. Some patients diagnosed with PL are followed radiographically or referred to a second provider, while others are not followed after incidental diagnosis. In this study we describe 74 cases of intrapancreatic lipomas from a single institution over a 12-year period to elucidate the radiologic and clinical natural history of pancreatic lipoma.

METHODS

In the period from January 2001 to December 2013, we selected patients over the age of 18 diagnosed with PL based on Ultrasound, CT, and MR imaging. Clinical data were coupled with review of the radiographic image. These patients were retrospectively followed to establish the significance of PL.

RESULTS

PL was identified in 0.012% of all patients undergoing cross-sectional imaging during the studied interval. Lipomas ranged in size at diagnosis from 0.1 cm to 4.8 cm. The majority of patients were asymptomatic at presentation. No patient required intervention or exhibited a change in lipoma diagnosis over a median follow up interval of 41.5 months (range 2-145). 47 patients underwent subsequent imaging with a median of two additional exams (range 2-113) over 31 months (range 1-18). 46/47 (98%) patients with subsequent images showed no discernible growth; 1/47 (2%) had a resolution of the lipoma.

CONCLUSIONS

Pancreatic lipomas are rare benign mesenchymal neoplasms that exhibit stable size and morphology. They are overwhelmingly asymptomatic. The natural history of pancreatic lipoma is benign. Short-term interval observation is prudent to prove stability and help differentiate from early liposarcoma. Extensive follow-up is not likely necessary for this benign lesion.

Incidental pancreatic lipomas diagnosed by computed tomography

OBJECTIVE

Fatty tumours of the pancreas are rarely reported. With the advent of the imaging techniques, diagnosis of such tumours based on radiologic imaging is increasing.

MATERIALS AND METHODS

Between June 2006 and June 2012, four patients with pancreatic lipomas that were diagnosed by computed tomography were reviewed retrospectively with regard to their imaging findings. There were 3 male and one female patient with a mean age of 60.8 years (from 53 to 67 years).

RESULTS

A single well-bordered nodular fatty lesion with well-delineated thin homogeneous capsule was seen in all patients. The mean densitometric measurement of the lesions was -76 Hounsfield units (HU) (from -83 HU to -63 HU). The size of the lesions was from 7 mm to 12 mm with a mean of 8.75mm. They were located in the tail, body and neck of the pancreas in two, one and one patient, respectively. There was no associated pancreatobiliary pathology. Histopathologic evaluation was not planned because of their incidental diagnosis in these asymptomatic patients.

CONCLUSION

Pancreatic lipomas are silent lesions, incidentally found during imaging procedures. They have specific computed tomography findings and do not require any additional diagnostic imaging.

Large pancreatic lipoma in a 69-year-old diabetic woman: diagnostic considerations

Pancreatic mesenchymal neoplasms are very rare pancreatic tumours. One of them is pancreatic lipoma, often diagnosed incidentally. We herein report a case of a large lipoma of the pancreatic head, diagnosed by computed tomography and magnetic resonance imaging and confirmed by ultrasound-guided fine needle biopsy (FNA) biopsy. Regarding its benign character, silent clinical course and excellent prognosis of invasive surgical removal was avoided. We propose here the diagnostic and therapeutic management of these rare pancreatic tumours. Computed tomography is the most accurate method to diagnose pancreatic lipoma. Nevertheless large tumours may need confirmation by FNA in differential diagnosis of liposarcoma.

Imaging features of the less common pancreatic masses

Contrast-enhanced multiphase CT and dynamic gadolinium-enhanced MR have been validated in the literature as outstanding modalities for the evaluation of pancreatic pathology. In addition to the more frequently seen pancreatic adenocarcinoma, neuroendocrine tumors of the pancreas and cystic lesions such as serous and mucinous cystadenomas and IPMNs, a variety of benign and malignant lesions may occur in the pancreas. The purpose of this pictorial essay is to review the imaging findings of a variety of uncommon, benign and malignant, pancreatic neoplasms.