FGFR2 and infantile convulsions and choreoathetosis: cHCC-CCAs shares various features such as histological findings of iCCA components, etiologies, and possible cell origin with small duct-type iCCA [1, 2, 22]; however, there were only a few studies on FGFR2 genetic alterations in cHCC-CCA, so far [4–7].