Mast cell leukemia with rapidly progressing portal hypertension

Reported herein is an autopsy case of mast cell leukemia, a rare form of systemic mastocytosis, complicated with portal hypertension. A 52-year-old woman presented with urticaria-like skin symptoms, anemia, and thrombocytopenia. Atypical mast cells (CD2+, CD25+, CD117+) with toluidine blue metachromasia were found in the peripheral blood and on bone marrow aspiration smears. Chemotherapy with cytosine arabinoside and idarubicin was ineffective and the patient died of multi-organ failure with rapidly progressing hepatosplenomegaly and large-volume ascites 3 months after admission. At autopsy the bone marrow, spleen, liver, and lymph nodes were extensively infiltrated by atypical tumor cells with occasional bi- or multi-lobated nuclei. They were positive for mast cell tryptase and possessed an activating mutation of the c-kitgene (D816V). Ascites (2200 mL) and non-ruptured esophageal varices with submucosal hemorrhage indicated the presence of severe portal hypertension. Although there was no evidence of liver cirrhosis, the hepatic sinusoids were clogged with tumor cells, with a tendency to be more severe in the perivenular areas, and the lumens of central veins were obliterated by tumor cell infiltration. The present case demonstrates that non-cirrhotic portal hypertension due to blocking of sinusoidal and venous flow could be a serious complication in mast cell leukemia.