Perivascular Epithelioid Cell Tumor (PEComa): A Rare Type of Liver Cancer.

Perivascular epithelioid cell tumor (PEComa) is a rare liver tumor, with few cases reported in the literature. Clinical decisions regarding patients diagnosed with PEComa are based on studies with small sample sizes. Differential diagnosis between PEComa and other types of liver lesions is challenging due to non-specific radiological findings associated with this type of liver mass. We report the case of a 51-year-old female patient followed at the outpatient hepatology clinic of Patras, General University Hospital, Greece, for chronic hepatitis B. The patient was asymptomatic, with positive hepatitis B surface antigen and normal liver function tests. An area with abnormal echogenicity and a diameter of 28 mm was observed in an abdominal ultrasound during routine follow up. Magnetic resonance imaging (MRI) was performed, and a mass with a diameter of 30.6 mm was found on surgical liver segment IV. A follow-up MRI 8 months later showed the lesion had increased to 36 mm and exhibited suspicious radiological characteristics. Surgical excision of liver segment IV was performed. Post-surgical pathological analysis of the tumor confirmed a diagnosis of PEComa, with no evidence of vascular or lymphatic invasion. The low mitotic index, the size of the tumor and the lack of nuclear atypia or diffuse pleomorphic morphology supported a favorable tumor behavior. In conclusion, PEComas are rare liver tumors without pathognomonic radiological features. Surgical excision of these masses is the safest treatment option, and post-surgical pathological analysis is essential for the diagnosis and prognosis of these patients.