Primary perivascular epithelioid cell tumor (PEComa) of the liver: Report of a case

Abstract

PEComa is very rare mesenchymal neoplasm which is formed by perivascular epithelioid cells and is characterized by dual melanocytic and myoid differentiation. Up to now only a very few cases of PEComa of the liver have been described worldwide. We herein present a patient who underwent a right hemihepatectomy for a huge tumor which could not be identified by imaging investigations. A final histopathologic examination revealed a benign epithelioid tumor with a solid growth pattern, abundant vascularity, and frequently dilated vascular channels. Immunohistochemically, the tumor cells were strongly positive for HMB-45, moderately positive for actin, and faintly positive for S-100, respectively. Based on the above findings, a diagnosis of a primary clear cell "sugar" tumor was established. Because the natural history of PEComas is mostly unpredictable, the patient has been closely followed up; however, no recurrence has so far been observed. Immunohistochemical findings play a crucial role in avoiding a misdiagnosis, and a surgical resection with an adequate margin of healthy tissue remains the gold standard of treatment. A long-term periodic follow-up is reasonable in all cases presenting with PEComa.

Perirenal perivascular epithelioid cell tumor (PEComa) coexisting with other malignancies: a case report

“…In agreement with others [3,16] the tumor cells in our case were S-100 negative. Contrary to us and to most reports, some authors reported patchy S-100 staining of PEComa cells [6,11]. In the present study the immunoexpression of CD-10 was negative in the tumor cells, although in some cases of PEComas positivity for CD-10 was noted.…”

“…To date, the extremely rare perivascular epithelioid cell tumor has been described in various anatomic locations: in lungs [1], pancreas [2], uterus [6,7], bone [8], retroperitoneum [9], ovary [10], liver [11], cutis [12], transverse colon [4] and in intraorbital location [3]. As was mentioned above, close perirenal location concerns only three cases of PEComas [5,13,14].…”

Contrast-enhanced ct and angiographic findings in hepatic perivascular epithelioid cell tumor

“…Tumor sizes ranged between 1.5 and 20 cm. Four patients had normal levels of serum AFP and were negative for hepatitis B surface antigen and anti-hepatitis C virus antigen (6,10,12,15); reports of the other 8 cases did not mention this. Two patients had a history of melanoma (13,14), and 1 had a history of GIST (8).…”

“…Generally, indigestion, loss of appetite, nausea, body weight loss, and intermittent colic pain can occur, and on physical examination tenderness to palpation and liver enlargement may be observed. These tumors have occurred in female patients aged from 13 to 70 years (median age: 55) (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Of the reported 12 cases (5-15), 6 cases occurred in the left lobe (7-9, 11, 14, 15), 4 in the right lobe (5,6,10,12), 1 in the caudate lobe (7), and 1 in the ligamentum teres (13).…”

“…Of these 5 cases, 3 cases showed early enhancement and early washout pattern and were misdiagnosed as HCC. The tumors have also been misdiagnosed as focal nodular hyperplasia, adenoma, or hepatocellular carcinoma (7,11,12,15).…”