Cholesterol granuloma in the pancreas accompanied by peritoneal disseminated lesions

Cholesterol Granuloma of the Liver Mimicking Malignant Tumor: A Case Report

Cholesterol granuloma is a benign, tumor-like lesion with an accumulation of cholesterol crystals in the tissue and is a consequence of a chronic inflammatory reaction. It commonly occurs in the middle ear but rarely in the liver. There is only one previous case report of cholesterol granuloma of the liver, which was caused by cholesterol hepatolithiasis. We report a case of cholesterol granuloma of the liver in a patient with no intrahepatic cholesterol stones; it was difficult to rule out malignant liver tumor preoperatively. The patient was a 79-year-old woman in whom a lesion in the liver was detected on abdominal ultrasonography. She was referred to our hospital for detailed examination and treatment. Abdominal contrast-enhanced computed tomography showed a 20 mm lesion with ring enhancement in the lateral segment of the liver during the arterial and delayed phases. Since a malignant tumor could not be ruled out radiologically, laparoscopic lateral segment hepatectomy was performed for definitive diagnosis and treatment. The resection specimen showed a yellowish-white lesion measuring 15 mm in diameter. Pathological examination showed a granulomatous lesion with cholesterol crystals surrounded by foreign body giant cells. The lesion was diagnosed as cholesterol granuloma of the liver. The postoperative course was good, and the patient was discharged on postoperative day 5. She was healthy, and no recurrence of the cholesterol granuloma was detected at the 5-month follow-up. This is the first case report of cholesterol granuloma of the liver mimicking a malignant liver tumor in a patient with no intrahepatic cholesterol stones.

Diagnosis of autoimmune pancreatitis with cholesterol granuloma mimicking intraductal papillary-mucinous carcinoma: A case report

INTRODUCTION

Pancreatic cysts are often observed incidentally on abdominal computed tomography (CT). For cysts involving intracystic nodules, malignant neoplasms such as intraductal papillary-mucinous carcinoma (IPMC) should be suspected. In contrast, cholesterol granuloma (CG) rarely occurs in the pancreas, and CG-associated autoimmune pancreatitis (AIP) has not yet been reported. To our knowledge, this is the first reported case of AIP with CG mimicking IPMC.

PRESENTATION OF CASE

A 56-year-old woman underwent abdominal CT for preoperative breast cancer screening. Asymptomatic polycystic lesions were detected in the pancreatic tail (maximum diameter, 5cm). Magnetic resonance cholangiopancreatography and endoscopic ultrasonography revealed main pancreatic duct obstruction and a lesion with intracystic nodules (maximum diameter, 10mm). Serum levels of pancreatic cancer tumor markers and IgG4 were within normal ranges. Because IPMC was suspected, distal pancreatectomy and splenectomy with regional lymphadenectomy were performed after surgery for breast cancer. Pathological examination of the specimen revealed no epithelial neoplasm; however, cholesterol crystals with foreign body giant cells were observed. Moreover, IgG4-positive plasma cells, diffuse lymphocyte infiltration, storiform fibrosis, and obliterative phlebitis were identified in the non-cystic pancreatic parenchyma. The final diagnosis was AIP with CG.

DISCUSSION

CG in the pancreas is rare and its pathogenesis remains unclear. The findings of the present case suggest that chronic inflammation due to AIP may cause local bleeding, and that a reaction to the leaked blood cells causes CG.

CONCLUSIONS

Although preoperative diagnosis may be difficult, AIP with CG should be considered as a differential diagnosis in pancreatic cysts involving nodular lesions.

Cholesterol granuloma of the anterior mediastinum with osseous metaplasia

Cholesterol granuloma is a well-characterized entity comprised of a foreign-body giant cell-reaction that forms in response to the presence of cholesterol crystals. It is usually found in the middle-ear or mastoid process in patients with diseases associated with chronic inflammation such as cholesteatoma and otitis media. They are rarely seen in the mediastinum. Osseous metaplasia is an exceedingly rare feature of cholesterol granulomas only reported twice in the literature. We report a case of a cholesterol granuloma of the anterior mediastinum with osseous metaplasia in a 75 year-old man that was found incidentally during urgent coronary artery bypass graft surgery.