Hepatic sclerosing haemangioma showing restricted diffusion: A case report with histopathologic correlation.

Hepatic sclerosing haemangiomas are rare benign tumours that are often difficult to distinguish from malignant tumours because these tumours do not show the typical imaging features of cavernous haemangiomas. We report a case of a sclerosing haemangioma that showed restricted diffusion and was difficult to differentiate from a malignancy. A 60-year-old female was referred to our hospital for evaluation of a hepatic mass that was incidentally diagnosed after a CT scan for right lower quadrant abdominal pain. Contrast-enhanced dynamic CT showed hepatic capsular retraction, with a small peripheral enhancement of the mass. The lesion appeared homogeneously hypointense on images, heterogeneously hyperintense on images, hyperintense on diffusion-weighted images, and hypointense on apparent diffusion coefficient (ADC) map. The lesion was suspected to be a cholangiocellular carcinoma and was surgically resected, but a final diagnosis of hepatic sclerosing haemangioma was made. Hepatic sclerosing/sclerosed haemangiomas are usually considered to show an increased ADC, which is useful for distinguishing them from malignant tumours. However, in this particular case, most of the lesion contained many obliterated or narrowed vascular channels, which might have acted as septa restricting the diffusion of water molecules in the intervening fibrous and/or hyalinised tissue. Hepatic sclerosing haemangiomas in the process of becoming completely fibrotic may show restricted diffusion, similar to malignant tumours.