Case Report
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 7, 2015; 21(17): 5432-5441
Published online May 7, 2015. doi: 10.3748/wjg.v21.i17.5432
Improving recognition of hepatic perivascular epithelioid cell tumor: Case report and literature review
Toshiya Maebayashi, Katsumi Abe, Takuya Aizawa, Masakuni Sakaguchi, Naoya Ishibashi, Osamu Abe, Tadatoshi Takayama, Hisashi Nakayama, Shunichi Matsuoka, Kazushige Nirei, Hitomi Nakamura, Masahiro Ogawa, Masahiko Sugitani
Toshiya Maebayashi, Katsumi Abe, Takuya Aizawa, Masakuni Sakaguchi, Naoya Ishibashi, Osamu Abe, Department of Radiology, Nihon University School of Medicine, Itabashi-ku, Tokyo 173-8610, Japan
Tadatoshi Takayama, Hisashi Nakayama, Department of Digestive Surgery, Nihon University School of Medicine, Itabashi-ku, Tokyo 173-8610, Japan
Shunichi Matsuoka, Kazushige Nirei, Hitomi Nakamura, Masahiro Ogawa, Department of Gastroenterology and Hepatology, Nihon University School of Medicine, Itabashi-ku, Tokyo 173-8610, Japan
Masahiko Sugitani, Department of Pathology, Nihon University School of Medicine, Itabashi-ku, Tokyo 173-8610, Japan
Author contributions: Maebayashi T drafted the manuscript; Maebayashi T, Abe K, Aizawa T, Sakaguchi M, Ishibashi N, Abe O, Matsuoka S, Nirei K, Nakamura H and Ogawa M examined the patient and diagnosed the benign liver tumor; Takayama T and Nakayama H performed the operation; Sugitani M diagnosed the hepatic PEComa.
Conflict-of-interest: The authors have no conflicts of interest to declare.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Toshiya Maebayashi, MD, PhD, Department of Radiology, Nihon University School of Medicine, 30-1 Oyaguchi kami-cho, Itabashi-ku, Tokyo 173-8610, Japan. maebayashi.toshiya@nihon-u.ac.jp
Telephone: +81-3-39728111-8328 Fax: +81-3-39582454
Received: October 16, 2014
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
Processing time: 208 Days and 12.1 Hours
Abstract

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.

Keywords: Angiomyolipoma; Tuberous sclerosis; Melan-A; Perivascular epithelioid cell tumor; Human melanoma black 45; Imaging

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.