Pancreatic Lipomas - Prevalence in Patients Undergoing Abdominal CT

Pancreatic Lipoma: A Pancreatic Incidentaloma Diagnosis with Computed Tomography

Lipoma of the pancreas is a rare benign tumour which is usually discovered incidentally on imaging. We present a case of an incidentally discovered pancreatic lipoma in a 79-year-old man with non-metastatic prostate adenocarcinoma who was referred to radiology for follow-up imaging. Fat-containing tumours originating from the pancreas are very rare. Most lipomas show characteristic features on imaging that allow their differentiation. We present the imaging features of a pancreatic lipoma on ultrasound, CT and MRI, discuss the differential diagnosis, and provide a brief review of the literature.

LEARNING POINTS

Pancreatic lipoma is a rare mesenchymal tumour that is being increasingly recognized.Pancreatic lipoma is commonly asymptomatic and incidentally detected.CT and MRI allow confirmation of the diagnosis and elimination of other differential diagnoses.

Fat-containing Retroperitoneal Lesions: Imaging Characteristics, Localization, and Differential Diagnosis

The complex anatomy of the retroperitoneum is reflected in the spectrum of neoplastic and nonneoplastic conditions that can occur in the retroperitoneum and appear as soft-tissue masses. The presence of fat within a retroperitoneal lesion is helpful in refining the differential diagnosis. Fat is easily recognized because of its characteristic imaging appearance. It typically is hyperechoic at ultrasonography and demonstrates low attenuation at computed tomography (-10 to -100 HU). Magnetic resonance imaging is a more ideal imaging modality because it has better soft-tissue image contrast and higher sensitivity for depicting (a) microscopic fat by using chemical shift imaging and (b) macroscopic fat by using fat-suppression techniques. Whether a lesion arises from a retroperitoneal organ or from the soft tissues of the retroperitoneal space (primary lesion) is determined by examining the relationship between the lesion and its surrounding structures. Multiple imaging signs help to determine the organ of origin, including the "beak sign," the "embedded organ sign," the "phantom (invisible) organ sign," and the "prominent feeding artery sign." Adrenal adenoma is the most common adrenal mass that contains microscopic fat, while myelolipoma is the most common adrenal mass that contains macroscopic fat. Other adrenal masses, such as pheochromocytoma and adrenocortical carcinoma, rarely contain fat. Renal angiomyolipoma is the most common fat-containing renal mass. Other fat-containing renal lesions, such as lipoma and liposarcoma, are rare. Fatty replacement of the pancreas and pancreatic lipomas are relatively common, whereas pancreatic teratomas are rare. Of the primary retroperitoneal fat-containing lesions, lipoma and liposarcoma are common, while other lesions are relatively rare. (©)RSNA, 2016.

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.

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.