Peliosis of the Liver and Spleen

Peliosis is a comparetively rare pathological entity characterized by the gross appearance of multiple cyst-like, blood-filled cavities within parenchy-matous organs. Peliosis has been related to several underlying debilitating illnesses, such as tuberculosis, hematological malignancies, AIDS, and posttransplant immunodeficiency, as well as intravenous drug abuse, chronic alcoholism, and in conjunction with intake of oral contraceptives or the abuse of anabolic-androgenic steroids. The classical pathoanatomical concept is based on the opinion that peliosis exclusively develops in organs belonging to the mononuclear phagocytic system (liver, spleen, bone marrow, and lymph nodes). In the liver, at gross inspection, the peliotic lesions give the cut sections a “swiss cheese” appearance. Microscopically, two different types of peliosis can be distinguished in the liver: (1) “parenchymal peliosis” consisting of irregular cavities that are neither lined by sinusoidal cells nor by fibrous tissue; and (2) “phlebectatic peliosis” characterized by regular, spherical cavities lined by endothelium and/or fibrosis. One of the differential diagnoses that most closely resembles peliosis hepatis is secondary hepatic congestion owing to veno-occlusive disease or the Budd-Chiari syndrome. In addition, electrocoagulation during surgery may cause vacuolated lesions within the liver parenchyma his-tologically resembling peliosis hepatis. In the spleen, the peliotic lesions may be arranged sporadically, disseminated, or in clusters in an uneven distribution pattern. Histologically, the cavities show frequently well-demarcated margins that may be focally lined by sinusoidal endothelium or totally lacking a clear cell lining. Differential diagnoses of peliosis of the spleen are hemangiomas and involvement of the spleen in hairy-cell leukaemia. Because the disease may culminate in spontaneous rupture of the affected organ and thus may mimick a violent death at autopsy, awareness of peliosis atautopsy, as well as an appreciation for the histopathological changes, is an important issue for the forensic pathologist.