Does hepatic adult capillary hemangioma exist?

Imaging and Pathologic findings of Hepatic Small Vessel Hemangioma

Hepatic small vessel hemangioma represents a distinct yet very rare pathologic entity of the liver. The entity has also been in the past referred to as adult capillary hemangioma of the liver and congenital noninvoluting hemangioma. Imaging findings are not definitive and biopsy or resection is ultimately necessary. Pathologically these represent vasoformative abnormalities with infiltrative margins that can potentially mimic hepatic angiosarcoma. Immunohistochemistry can help differentiate hepatic small vessel hemangioma from angiosarcoma. Given the infiltrative growth pattern and unknown outcomes, resection and or close follow up has been recommended. Recently the term hepatic small vessel neoplasm has been coined in view of the unknown outcomes and some concerning findings on molecular analysis. We report 2 cases of this unusual entity and describe its imaging, gross pathologic, histopathologic, and immunohistochemical features.

Hepatic small vessel neoplasm, a rare infiltrative vascular neoplasm of uncertain malignant potential

Characteristic but rare vascular neoplasms in the adult liver composed of small vessels with an infiltrative border were collected from an international group of collaborators over a 5-year period (N=17). These tumors were termed hepatic small vessel neoplasm (HSVN), and the histologic differential diagnosis was angiosarcoma (AS). The average age of patients was 54years (range, 24-83years). HSVN was more common in men. The average size was 2.1cm (range, 0.2-5.5cm). Diagnosis was aided by immunohistochemical stains for vascular lineage (CD31, CD34, FLI-1), which were uniformly positive in HSVN. Immunohistochemical stains (p53, c-Myc, GLUT-1, and Ki-67) for possible malignant potential are suggestive of a benign/low-grade tumor. Capture-based next-generation sequencing (using an assay that targets the coding regions of more than 500 cancer genes) identified an activating hotspot GNAQ mutation in 2 of 3 (67%) tested samples, and one of these cases also had a hotspot mutation in PIK3CA. When compared with hepatic AS (n=10) and cavernous hemangioma (n=6), the Ki-67 proliferative index is the most helpful tool in excluding AS, which demonstrated a tumor cell proliferative index greater than 10% in all cases. Strong p53 and diffuse c-Myc staining was also significantly associated with AS but not with HSVN or cavernous hemangioma. There have been no cases with rupture/hemorrhage, disseminated intravascular coagulation, or Kasabach-Merritt syndrome. Thus far, there has been no metastasis or recurrence of HSVN, but complete resection and close clinical follow-up are recommended because the outcome remains unknown.

Adult capillary hemangioma of the liver: case report and literature review

Primary hepatic capillary hemangioma in adults is very rare. Here, we report a case of hepatic capillary hemangioma in a 71-year-old woman. She had abnormal liver function tests, and abdominal sonography revealed a 2-cm nodular lesion and fatty liver. Computed tomography scan revealed a hypervascular tumor. During 2 years' follow-up, the hepatic tumor enlarged to 3 cm in diameter. Serological tests showed no evidence of chronic viral hepatitis or increased level of alpha-fetoprotein. In fear of hepatocellular carcinoma, she received atypical hepatectomy. Microscopically, the tumor turned out to be a capillary hemangioma in a background of steatohepatitis. We searched the literature, and only six similar cases were found. We made a brief review of this rare disease entity and described its clinicopathological features.