[Pathology along the liver sinusoids: intrasinusoidal findings].

Pathological findings in the liver sinusoids are mostly caused by extrahepatic or systemic diseases. Unclear fever, hepatosplenomegaly, portal hypertension or a mild elevation of liver enzymes are reasons for a liver biopsy leading to path-breaking diagnoses. Reactive intrasinusoidal lymphocytosis, especially with Epstein-Barr virus infections, has to be differentiated from predominantly intrasinusoidal lymphoproliferative malignancies. Intrasinusoidal megakaryocytes can be the first sign of a myeloproliferative or myelodestructive disease. Intrasinusoidal carcinosis and melanomatosis might present radiologically without tumor lesions and are easily overlooked histologically, in particular, if the critical cells have a similar size to hepatocytes. This also applies for intrasinusoidal storing macrophages. Gaucher's disease type I, and some other subtypes of inborn storage diseases might present for the first time in adulthood by hepatomegaly and Kupffer cell hypertrophy. Accompanying perisinusoidal fibrosis and immunohistochemical staining (CD68) can help to detect the large pale intrasinusoidal macrophages. In immunocompromized patients with fever, particular attention must be paid to intracellular agents, especially atypical mycobacteria and yeasts in non-granulomatous nested or dispersed Kupffer cells. Leishmaniasis with amastigotes in macrophages is accompanied by reactive sinusoidal plasmocytosis.