Published online May 7, 2015. doi: 10.3748/wjg.v21.i17.5432
Peer-review started: October 18, 2014
First decision: December 2, 2014
Revised: March 15, 2015
Accepted: March 31, 2015
Article in press: March 31, 2015
Published online: May 7, 2015
A 58-year-old man presented with the chief complaint of abdominal bloating and was incidentally found to have a liver tumor. As diagnostic imaging studies could not rule out malignancy, the patient underwent partial resection of segment 3 of the liver. The lesion pathologically showed eosinophilic proliferation, in addition to immunohistochemical positivity for human melanoma black 45 and Melan-A, thereby leading to the diagnosis of a hepatic perivascular epithelioid cell tumor (PEComa). A PEComa arising from the liver is relatively rare. Moreover, the name ‘PEComa’ has not yet been widely recognized, and the same disease entity has been called epithelioid angiomyolipoma (EAML), further diminishing the recognition of PEComa. In addition, PEComa imaging findings mimic those of malignant liver tumors, and clinically, this tumor tends to enlarge. Therefore, a PEComa is difficult to diagnose. We conducted a systematic review of PEComa and EAML cases and discuss the results, including findings useful for differentiating perivascular epithelioid cell tumors from malignant liver tumors.
Core tip: Hepatic perivascular epithelioid cell tumors (PEComas) are very rare. This is the first review to investigate and compare the results of both PEComa and epithelioid angiomyolipoma patients. As PEComas are primarily benign tumors, surgical interventions may be avoidable. The key findings in the differential diagnosis of this tumor include a blotchy vascular pattern within the tumor and no hemorrhage within tumors less than 7 cm at the maximum diameter. Furthermore, if PEComas have hemodynamic features similar to those of hepatic angiomyolipomas, then the patterns of the drainage veins would very likely be useful for differentiating hepatocellular carcinomas from PEComas, as observed in our case.