Hepatic Kaposi Sarcoma after Kidney Transplantation: A Case Report

Abstract

Kaposi sarcoma is an undisputed malignancy associated with a heightened relative risk after transplantation. Similar to other causes of Kaposi's sarcoma, cutaneous involvement is typical in post-transplant patients; however, visceral involvement rarely occurs. We report a rare case of de novo hepatic Kaposi's sarcoma manifesting as an ill-defined infiltrative lesion in the left lobe of the liver in a patient who was immunosuppressed for 9 months after a kidney transplantation using ultrasonography, CT, MRI, and fluorodeoxyglucose-PET.

Keywords: Kaposi Sarcoma; Kidney Transplantation; Liver.

Fig. 1. Hepatic Kaposi sarcoma in a 65-year-old male after a kidney transplant.

A. CT images show contour bulging of the left lobe and ill-defined slight hyperenhancement along segment III artery in the arterial phase (left, arrows) and hypoattenuation in portal phase with congestive changes of intervening hepatic parenchyma (middle, arrows). Marked enlargement with conglomeration of lymph nodes in periportal, aortocaval, left para-aortic, and bilateral common iliac areas are noted (right, arrows). B. MR images best show the extent of disease in the hepatobiliary phase, appearing hypointense compared to normal parenchyma, along segment III portal vein (P3) and its branches (first row left, arrows). Left duct obliteration by the mass and dilatation of segment II intrahepatic duct (B2) and segment III intrahepatic duct (B3) ducts are noted on T2-weighted images (second row left and third row left, arrows). The lesion shows poor enhancement compared to normal parenchyma in post 1-min and 3-min images with congestive changes of intervening hepatic parenchyma (first row middle and right, arrows). The lesion does not show signal drop on inphase and out-of-phase images (second row middle and right, arrows) and shows diffusion restriction (third row middle and right, arrows). C. Fluorodeoxyglucose-PET showing an ill-defined hypermetabolic mass in the left lobe of the liver and multiple hypermetabolic retroperitoneal lymph nodes. D. Ultrasound images show diffuse hypoechoic infiltrative lesion along segment III portal triad (left, arrows) and peripheral intrahepatic duct dilatations (right, arrows). E. Histopathological specimens show vascular and spindle cell proliferative lesion (hematoxylin & eosin stain, left, arrows). Immunohistochemistry staining reveals Kaposi sarcoma-associated herpesvirus patch positive (middle, arrows) and ERG positive (right, arrows). F. After modification of immunosuppressant at the time of diagnosis, markedly decreased extent of primary lesion (arrows) and retroperitoneal lymph nodes are noted, with volume shrinkage of left lobe of the liver. ADC = apparent diffusion coefficient, DWI = diffusion-weighted imaging, ERG = ETS-related gene, T2WI = T2-weighted imaging