Lipomas of the pancreas

Pancreatic lipoma: a pancreatic incidentaloma; diagnosis with ultrasound, computed tomography and magnetic resonance imaging

Pancreatic lipomas are rare. We present a case of incidentally discovered pancreatic lipoma in a 45-year-old female suffering from metastatic ovarian carcinoma who was referred to radiology for follow-up imaging. Fat-containing tumours originating from the pancreas are very rare. Most lipomasshow characteristic features on imaging that allow their differentiation. In most cases, accurate diagnosis is attained without any histopathological confirmation. We present the imaging features of pancreatic lipoma on ultrasound, CT scan and MRI, the differential diagnosis and a brief review of the literature.

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.

Pancreatic Lipomas - Prevalence in Patients Undergoing Abdominal CT

BACKGROUND

Pancreatic lipomas are reported to be rare but their prevalence is unknown. This study examined the prevalence of pancreatic lipomas in a sample of patients undergoing abdominal computed tomography.

MATERIAL/METHODS

Retrospective review of 100 abdominal computed tomographic scans.

RESULTS

In 6 patients small pancreatic lipomas were found. There was no predominance in location or gender. The lipomas measured between 4 and 12 mm. All lipomas were incidental findings unrelated to patients' symptoms.

CONCLUSIONS

Pancreatic lipomas seem to be quite a common finding and can be found in 6% of patients undergoing abdominal CT. Radiologists should be aware of this finding to establish proper differential diagnosis.

Pancreatic lipoma: An incydentaloma which can resemble cancer - analysis of 13 cases studied with CT and MRI

Background:

The purpose of this article is to present computed tomography (CT) and magnetic resonance imaging (MRI) findings of rare pancreatic lipomas.

Material/Methods:

The analysis covered 13 patients (7 men and 6 women, aged 47–88, average: 65.6 years), with 13 pancreatic lipomas, whose cases constituted the basis for 10 contrast-enhanced CT and 5 MRI studies.

Results:

Lipomas measured from 6 mm to 32 mm (average 12.8 mm) and were located in the pancreatic head (n=7), body (n=2), tail (n=3) and uncinate process (n=1). Most lesions (n=11) were homogenous, well-circumscribed.

On contrast-enhanced CT scans, macroscopic fat (<−30 HU) was present in 9 lipomas. In one case (10 mm lesion) the density was −20 HU and the lesion was poorly circumscribed with septations, which altogether made it difficult to precisely characterize its contents.

On MR scans fat was demonstrated in all studied cases (n=5).

Conclusions:

Lipomas are rare, small, homogenous and well-circumscribed pancreatic tumours. The most important feature, decisive for the diagnosis and distinguishing them from pancreatic carcinoma, is detection of fatty tissue on CT and MR scans. In these cases differential diagnosis includes other rare fatty tumours of the pancreas (focal fatty infiltration, teratoma, liposarcoma).

Lipoma of the pancreas, a case report and a review of the literature

Lipomas of the pancreas are very rare. There are fewer than 25 reported cases of lipoma originating from the pancreas. We present a case of pancreatic lipoma in a 61-year-old woman with magnetic resonance imaging findings and confirmatory histological findings. We discuss and highlight the radiological features distinguishing a pancreatic lipoma from other fatty lesions of the pancreas and pancreatic liposarcoma and provide a brief review of the literature.

Infarction of lesser omental fat mimicking an exophytic pancreatic tumor by sonography

We report a case of infarction of lesser omental fat in a 30-year-old woman who presented with epigastric pain. Sonography revealed a painful echogenic mass in the epigastrium that could not be separated from the adjacent hyperechoic pancreas and mimicked an exophytic pancreatic tumor. On CT, the mass was identified as an inflammatory lipomatous mass in the lesser sac, leading to the diagnosis of infarction of lesser omental fat. The patient was successfully treated conservatively.

Incidental pancreatic lipomas: computed tomography imaging findings with emphasis on diagnostic challenges

PURPOSE

The purpose of this study was to describe the computed tomography (CT) findings of pancreatic lipomas of 9 cases, with emphasis to diagnostic challenges.

METHODS

Between March 2006 and April 2008, 9 patients with pancreatic lipomas that were diagnosed by CT were reviewed in the present study. Clinical data and CT features of these 9 cases were retrospectively analysed. The patient population included 5 men and 4 women, aged 42-81 years (mean age, 65.8 years). The patients were followed up for at least 2 years with control CTs.

RESULTS

In all 9 cases, a well-bordered nodular fat density lesion was incidentally detected in the pancreas. Four of the lesions had a lobulated contour, and 2 of them had septations. Two of the lipomas were located in the head, 3 in the neck, 3 in the corpus, and 1 in the tail. The CT densitometric values were between -90 and -120 HU, with a mean value of -106 HU. No pancreatic or biliary dilatation or compression to the adjacent structures was seen. All the cases had control CTs, and the lipomas remained unchanged during the follow-up period. Histopathologic confirmation of the diagnosis was not planned for the cases.

CONCLUSION

Lipomas are rarely encountered in the pancreas. They often are diagnosed coincidentally as small, well-circumscribed, encapsulated, homogeneous, mature adipose masses on imaging studies. Imaging follow-up strategy or histopathologic confirmation is not necessary in asymptomatic patients.

Uncommon solid pancreatic neoplasms: ultrasound, computed tomography, and magnetic resonance imaging features

This article reviews the ultrasound, computed tomography, and magnetic resonance imaging features of rare solid tumors of the pancreas with attention to distinctive imaging appearances, which can help radiologists to discriminate between the different entities. Various uncommon solid pancreatic neoplasms, including exocrine and endocrine epithelial tumors, mesenchymal tumors, and metastases, are reviewed, with emphasis on key differential points, including morphologic features and patterns of contrast enhancement.

[Pancreatic incidentalomas. Correct assessment and therapy]

Due to recent advances in CT/MRI technology, incidentalomas of the pancreas are detected with increasing frequency. Pancreatic incidentalomas should be differentiated into solid and cystic tumors. In both subgroups definitive classification of the tumor is often not possible. Operative therapy is recommended in premalignant or malignant pathologies. Thus solid incidentalomas should be resected independently of their size, if the patient is without serious comorbidities. In case of cystic incidentalomas, benign cystic lesions should be excluded as far as possible. Otherwise they should be resected if their size is >or=2 cm. In case of IPMN with specific risk factors, resection is recommended when the tumor size exceeds 1 cm.

Imaging of uncommon tumors of the pancreas

In this article, the radiological manifestations of a variety of uncommon tumors of the pancreas are illustrated, with emphasis placed on their appearance at helical CT. Islet cell tumors, because of their vascularity, typically present as masses that are hyperattenuating to the normal pancreas at dual-phase helical CT. Lymphomas appear as hypoattenuating focal lesions or can diffusely infiltrate the gland. Absence of biliary tree dilatation, despite the presence of a bulky tumor, or associated extensive retroperitoneal adenopathy should offer clues to the diagnosis. Pancreatic metastases are usually seen in patients with advanced cancers, although isolated metastases from renal cell carcinoma can occurs years after the original tumor; such patients may benefit from surgical resection. Finally, the appearance of some rare neoplasms of mesenchymal origin is discussed.

Lipoma of the pancreas: MRI findings

Lipomas of the pancreas are very rare. Focal fatty infiltration of the pancreas is an entity that should be differentiated from a pancreatic lipoma. In this report the MRI findings of an incidentally found pancreatic lipoma are presented and the role of MRI in the differentiation of pancreatic lipoma and focal fatty infiltration of the pancreas is discussed.

Mesenchymal tumors of the pancreas: CT findings

This article reviews the CT imaging features of the most frequent mesenchymal tumors of the pancreas and stresses important distinctive patterns that may help distinguish specific entities. Various neoplasms (lymphangioma, lipoma, teratoma, pancreatoblastoma, schwannoma, neurofibroma, lymphoma, and sarcoma) are reviewed, with key differential points (structure, fatty and water densities, calcification, pattern of contrast enhancement, vascularization, and necrotic or regressive changes) emphasized. In addition, epithelial tumors are considered in the differential diagnosis.