Unique MRI findings for differentiation of an early stage of hepatic alveolar echinococcosis

CT scan and ultrasonography images revealed two small uniformly low-density and hypoechoic lesions in the liver, respectively, 7 years after curative resection of rectal cancer, in a 74-year-old man. The area of the liver including the two lesions was segmentally resected. Two lesions were histopathologically confirmed as early but active stage alveolar echinococcosis (AE) caused by accidental ingestion of eggs of the fox tapeworm, Echinococcus multilocularis . This case is very unique and rare, since early stage hepatic AE cases have only accidentally been confirmed from cases in which malignant hepatic tumours were suspected, and because two independent AE lesions were detected. Abdominal MRI showed two isointense tumour lesions with small areas of high-signal intensity in their centres on T2-weighted images. MRI findings appear to reflect the macroscopic view and microscopic findings of early stage AE with active cyst in the centre of each hepatic lesion well.