Liver biopsy of the patient with drastically increased liver stiffness due to mast cell infiltrates. (a) Infiltration of portal tract and liver sinusoids with neoplastic mast cell like cells (HE). (b) CD117 immunostaining shows nodular infiltration with mast cells. (c) Portal, periportal, and perisinusoidal fibrosis (modified Gomori stain. 200). (d) CK7 immunostain identifies neoplastic mast cells that infiltrate the portal bile ducts and ductular structures 200.