A case of hepatic angiomyolipoma

Abstract

Background : Angiomyolipoma (AML) is a relatively rare benign tumor consisting of smooth muscle, blood vessels, and mature fat cells. We report a case of hepatic AML focusing on cytological findings.
Case : A 60-year-old woman reporting irregular vaginal bleeding and diagnosed with Grade 2 endometrioid adenocarcinoma based on endometrial biopsy and admitted for surgery was found in preoperative computed tomography (CT) to have an irregular tumor at S6 of the liver. Based on a suspicion of metastasis from endometrial cancer, partial hepatectomy was conducted preceding gynecologic surgery. AML was diagnosed based on the immediate intraoperative histology of surgical specimens. Immediate imprint cytology showed inflammatory cells, fat cells, and spindle-shaped cells in the background. Spindle-shaped cells formed large clusters with clear margins, which contained capillary blood vessels, mature fat cells, and large and small atypical cells. Some atypical cells had irregular nuclei, large nucleoli, and intranuclear vacuoles and required a differential diagnosis of benign or malignant tumor. Although a nonepithelial tumor was suspected, we could not determine whether the tumor was benign or malignant. The definitive cytological diagnosis was ClassIII. Large atypical cells were human melanosome (HMB45) positive in immunostaining.
Conclusion : Patients with AML may present large atypical cells that require a differential diagnosis regarding malignancy, emphasizing the need for careful observation in diagnostic cytology.