Hepatic PEcoma: an unusual tumor in an infrequent location

Perivascular epithelioid cell neoplasms (PEComas) are a tumor family defined as such just a couple of decades ago. They make an unusual group of neoplasms, which can appear in different locations of the organism. PEComas are usually considered to be benign tumors, but there are some histological features that make some subgroups suspicious of malignancy. The treatment of these tumors consist in their surgical resection, with no current effective complementary oncological treatment known. We present the clinical case of a woman that underwent surgery for a resection of a hepatic lesion labeled afterwards as a PEComa with malignant features.

[Hepatic epithelioid angiomyolipoma/PEComa and focal nodular hyperplasia in a patient with a previous history of cutaneous melanoma]

Hepatic perivascular epithelioid cell tumors (PEComas) are uncommon mesenchymal neoplasms. PEComas concurrent with other hepatic lesions is a very rare occurrence, with only two previously reported cases. We report a primary hepatic PEComa associated with focal nodular hyperplasia in a patient with a previous history of cutaneous melanoma. Diagnostic imaging studies suggested a hepatic adenoma and the patient underwent a segmentectomy. The tumor was mainly composed of epithelioid cells, adipose tissue and smooth muscle fibers intermixed with blood vessels. The neoplastic cells were diffusely immunoreactive for HMB-45, Melan-A and smooth muscle actin, but not for Hepatocyte, S100, MITF or BRAF. Molecular studies were negative for BRAFV600 mutation. The final diagnosis was hepatic epithelioid angiomyolipoma/PEComa. The differential diagnosis of hepatic PEComa is discussed.