BACKGROUND: Hepatic angiomyolipoma (HAML) is a rare mesenchymal liver tumour which belongs to the family of perivascular epithelioid cell tumours (PEComas). It is typically composed of blood vessels, smooth muscle, and adipose cells, and shows strong immunoreactivity for HMB-45.
UNASSIGNED: A 57-year-old woman was referred to our hospital with an unclear liver lesion. A fine needle biopsy revealed a suspicion of hepatic angiomyolipoma with extramedullary haematopoiesis. Preoperative imaging revealed a tumour 17 cm in diameter in the left liver lobe segments II and III. A lobectomy of the left lobe segments II and III was performed. The pathological diagnosis of hepatic angiomyolipoma was obtained.
CONCLUSIONS: Variations in the predominance of the tissue components in HAML impedes diagnosis based on imaging alone. The most promising evidence of HAML is the histological identification of lipomatous, myomatous, and angiomatous tissue combined with immunohistochemical positivity for HMB-45. Although the tumour is considered benign, some cases have been described with malignant behaviour. Surgical resection should be considered in case of symptoms, inconclusive biopsy, or growth in follow-up. Other surgical indications may include aggressive patterns such as vascular invasion, p53 immunoreactivity, or rapidly proliferating tumour cells.
CONCLUSIONS: HAML is a rare liver tumour. In patients with symptoms, uncertain diagnosis, or tumour growth, surgical resection should be performed according to oncological criteria.

Hepatic Angiomyolipoma (HAML) is a rare mesenchymal liver tumour assumed to be predominantly benign, although incidental cases with malignant behaviour such as invasive growth, recurrence after resection and metastases have been reported. The aim of this systematic review was to assess the biological behaviour, estimate the risk of HAML related mortality and recommend on a justifiable management strategy. We performed a systematic literature search in Embase, Medline, Web-of-Science, Scopus, Pubmed Publisher, Cochrane and Google Scholar. We included all articles published from inception until March 2016 which reported on follow-up of various treatment strategies. We included 18 articles reporting on 292 patients. Male:female ratio was estimated at 1:3 with gender not reported in 31 cases. Of 292 patients 247 were treated with surgery, including one liver transplant, seven with chemotherapy or Sirolimus, three with embolization, and 35 conservatively. Recurrence after resection was described in 6/247 (2.4%) with pathologically proven HAML resulting in metastases and death in 2/247 (mortality rate 0.8%). Progression was described in 6/35 patients treated conservatively (21.4%). Two of 12 patients with malignant behaviour of HAML had an epithelioid-type HAML, of the remaining 10 histological subtype was undefined. With a risk estimate of 0.8% in surgically treated patients HAML related mortality is very low. Biopsy is indicated when imaging is inconclusive. In case of certain HAML diagnosis on imaging conservative management with annual imaging is justified. Resection should be considered in case of symptoms, inconclusive biopsy or growth in follow-up.

Angiomyolipoma (AML) arising in the liver is rare and usually benign, but it occasionally has malignant potential. A 58-year-old man with a liver tumor identified by a previous doctor with features suggestive of hepatocellular carcinoma on computed tomography (CT) underwent anterior segmentectomy of the liver in 2006. Microscopically, the tumor was composed of exclusively epithelioid cells that were scatteredly positive for human melanoma black 45 on immunohistochemistry. Accordingly, primary hepatic epithelioid AML (eAML) was diagnosed. The patient was subsequently referred to our hospital for follow-up after hepatectomy. He had event-free survival for nearly 7 years. In 2013, two well-defined round nodules were detected in the right lung field by chest CT, and partial pneumonectomy was performed for diagnosis and treatment. Histological examination of the resected lung tissue showed that it was morphologically and immunohistochemically identical to his primary hepatic eAML, leading to the diagnosis of pulmonary metastasis. This paper demonstrates a rare case of malignant hepatic eAML with late recurrence in the lung after hepatectomy.

Hepatic angiomyolipoma (AML) is known as a rare benign tumor with invasive growth. In the past, some of these tumors were misdiagnosed as hepatocellular carcinomas, because of the similar pattern on imaging studies. Recently, correct diagnoses have been increasing, with the development of HMB-45 immunohistochemical staining, and it appears that the majority of these tumors behave as benign tumors. However, there are not a few cases which have resulted in fatal courses because of recurrence and metastasis of the tumor. The clinical features and signs of the malignant potential of this tumor are unknown; thus, the management and treatment of the tumor are still controversial. Here in this article, we report a case of hepatic AML which showed a size increase of 175% in 1 year, and portal vein thrombosis detected by angiography. During a follow up of 3 years after a curative hepatic lobectomy, no metastasis or recurrence was seen. Review of the literature suggests that portal vein thrombosis could be one of the markers of the malignant potential and transformation of this tumor. Therefore, in this paper, we recommend surgical treatment of hepatic AML in which there is a strong suspicion of portal vein thrombosis.