Liver findings in generalized mastocytosis. A clinicopathologic study.

Although the liver is one of the four organs most often involved in generalized mastocytosis (GM), little is known about macroscopic and microscopic liver findings in this rare disease. This study included 182 patients with GM (confirmed in most by bone marrow histologic study), comprising 52 cases of our own and 130 reported in the literature. Hepatomegaly was found in 131 (72%) of the 182 patients, cirrhosis in seven (4%), and periportal fibrosis in 25 (14%). Mast cell (MC) infiltration of the liver was confirmed histologically in 77 (42%). Liver specimens were available for further histologic investigation in 11 of our own cases of GM. Nine of these contained MC aggregates. Mast cells were found predominantly in the portal tracts but numerous MC also were loosely scattered throughout the sinusoids. Diagnostic confusion of GM with reactive lesions of the liver is unlikely to occur since MC, according to our own observations and the available literature, are found only in very low numbers in normal liver tissue, where they occur mainly in the portal tracts. Reliable identification of MC does, however, require special stains, like Giemsa, toluidine blue, or naphthol AS-D chloroacetate esterase.