Nodular macroregenerative tissue as a pattern of regeneration in cholangiopathic disorders

Published case series have described central hepatic macroregenerative nodules or masses as a common feature of Alagille syndrome. Our experience suggests this regenerative pattern can be seen more generally in cholangiopathic disorders.

To define the frequency of central regenerative tissue in Alagille syndrome and other cholangiopathic disorders and to describe the typical appearance of such regenerative tissue.

We conducted a retrospective study of CT and MR imaging performed in children and young adults with cholangiopathic disorders between January 2000 and June 2016. Two pediatric radiologists reviewed images in consensus for the presence and features of macroregenerative tissue. Tissue histopathology, when available, was retrieved from the medical record.

Of 226 patients with cholangiopathic disorders, 23% (52/226) had macroregenerative tissue, and this tissue was central in 96% (50/52). Tissue was well defined and mass-like in 38% (20/52). Regenerative tissue was most common among the subset of patients with Langerhans cell histiocytosis with hepatic involvement (71%, 5/7) and was identified in 43% (16/37) of patients with Alagille syndrome. Regenerative tissue was iso- to hyperintense on T1-weighted MR sequences in 96% (50/52) of cases and hypointense on T2-weighted MR imaging in 94% (48/51). Arterial phase hyperenhancement was present in only five patients (12% of 43), none of whom showed portal venous phase washout. Histopathology was available for 20 cases, all showing benign regenerative tissue.

Central mass-like regeneration appears to be a common regenerative pattern in cholangiopathic disorders and should not be mistaken for malignancy.