Systemic mastocytosis: a rare cause of noncirrhotic portal hypertension simulating autoimmune cholangitis--report of four cases.

Four patients with systemic mastocytosis, two men and two women, are presented. Three of them (patients 1, 2, and 4) developed portal hypertension and ascites without histological evidence of cirrhosis in liver biopsy. The remaining patient (patient 3) had severe bone lesions with multiple vertebral fractures. None of the patients had skin or lymph node involvement. Two patients (patients 1 and 2) died 12 and 9 months after diagnosis with acute nonlymphocytic leukemia and overt mastocytic leukemia, respectively, while the other two (patients 3 and 4) are alive 58 and 14 months after diagnosis. Treatment with hydroxyurea or cytosine arabinoside had not any beneficial effect in two patients, while a substantial amelioration of back pain had been obtained by local irradiation and recombinant human interferon-alpha-2b administration in one patient (patient 3). All patients had laboratory findings compatible with autoimmune cholangitis. We concluded that systemic mastocytosis is a rare cause of noncirrhotic portal hypertension often simulating autoimmune cholangitis and leading to the erroneous diagnosis of liver cirrhosis. Diagnosis is based on the presence of mast cells in Giemsa-stained liver histological sections, and it may be confirmed by immunohistochemical detection of tryptase in the cytoplasm of these abnormally proliferating cells.