We report two cases of a nonparasitic solitary huge liver cyst. The first case, that of a 42-year-old woman, was admitted with a chief complaint of upper abdominal pain. Computed tomography (CT) scans revealed a huge cyst, 10 cm in diameter, in segments 4 and 5 of the liver, and spontaneous rupture of the cyst with intracystic hemorrhage. Her general condition was improved by transcatheter arterial embolization (TAE). Percutaneous cystic needle aspiration cytological examination revealed no malignant cells, so she was discharged. After 3 weeks, however, the cyst had increased in size, and simple cystectomy was performed. Histological examination proved the cyst to be benign. The patient in the second case, a 70-year-old man, was admitted with epigastric discomfort and obstructive jaundice. CT scans revealed a huge liver cyst, 18 x 15 cm, in the right lobe of the liver, with dilation of the bile duct in the lateral segment. Magnetic resonance cholangiopancreatography showed compression of the left hepatic duct by the cyst and dilation of the bile duct in the lateral segment. Endoscopic retrograde cholangiopancreatography disclosed no communication between the bile duct and the cyst. Percutaneous transhepatic cyst drainage was performed, and minocycline hydrochloride was infused. The cyst was reduced in size, and the reduction has been maintained for 20 months since treatment.
A 67-year-old woman was referred with an abnormal finding on an abdominal echogram but presented with no symptoms; a pancreatic tail tumor was detected by ultrasonography. Biochemical examinations showed slight elevation of serum carcinoembryonic antigen level. The lesion was resected by tail and body pancreatectomy and her postoperative course was uneventful. Seven years and 4 months after the initial operation, however, her serum level of carbohydrate antigen 19-9 was found to be elevated, and a recurrence of pancreatic cancer was suspected. Examinations revealed a mass in the head of the remnant pancreas. The lesion was radically resected by total remnant pancreatectomy. Histological examinations showed that the initial tumor was a well differentiated tubular adenocarcinoma, while the second tumor was characterized as a moderately differentiated tubular adenocarcinoma. The surgical margins of the distal pancreatectomy specimen were free of atypical cells. Therefore, the position of the second lesion diminished the likelihood that it had developed by intrapancreatic metastasis. This suggests that the second carcinoma in the head of the pancreas may have been a second primary lesion.
Background
CRTC1-MAML2 fusion is often detected in low- or intermediate-grade salivary mucoepidermoid carcinoma (MEC), and it is associated with a favorable clinical course. Primary MEC of the liver is an extremely rare, aggressive tumor, and no study has investigated CRTC1-MAML2 fusion.
Case presentation
A 79-year-old Japanese female presented with an approx. 5-cm hepatic mass lesion. We surgically resected the lesion under the clinical diagnosis of intrahepatic cholangiocarcinoma. The histological and immunohistochemical findings were consistent with high-grade MEC, consisting of squamoid, mucin-producing, and intermediate tumor cells. Our RT-PCR analysis revealed the presence of CRTC1-MAML2 fusion. This fusion gene was further confirmed by direct sequencing. The patient is still alive almost 10 years after the surgery.
Conclusion
This is the first case report of primary MEC of the liver with CRTC1-MAML2 fusion, with long survival. The present case has significant implications for the entity of primary MEC of the liver which should be distinguished from adenosquamous carcinoma.
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