text: <unk>  is a rare group of mesenchymal vascular neoplasms.<unk> s commonly present with an enlarging mass and have been reported in the head, neck, lungs, lymph nodes, pleura, retroperitoneum, or stomach.<unk> s may be benign or malignant and tend to occur around medium to large venous structures.<unk>  may be classified into 4 groups including epitheloid<unk>  (most common), kaposiform<unk> , retiform<unk> , and infantile<unk> . The prevalence of<unk>  is approximately 1 per 100,000 individuals worldwide.
  The majority of patients with<unk>  are symptomatic at the time of diagnosis. Early clinical features of<unk>  are often unspecific and may include abdominal pain, mass, weight loss, or fatigue. On CT scan, characteristic findings of hepatic<unk>  may include multiple hypo-attenuating lesions in both hepatic lobes which coalesce to form larger confluent hypo-attenuating regions in a peripheral or subcapsular distribution, halo or target pattern of enhancement in larger lesions, and a subcapsular lesion (with capsular retraction). Surgical resection, radiotherapy, and chemotherapy are often the treatment of choice for<unk> .
option_0: Hemangioendothelioma
option_1: Mesothelioma
option_2: Kaposiform hemangioendothelioma
option_3: Infantile hemangioendothelioma
option_4: Pulmonary artery sarcoma
option_5: Pulmonary capillary hemangiomatosis
option_6: Sarcoma
option_7: Alveolar soft part sarcoma