Mesenchymal tumors of the liver: their frequency and histopathological diagnostic problems in surgical investigations
Primary mesenchymal tumors of the liver are rarely observed. Histopathological diagnosis can be very difficult, in needle biopsies especially. This is a great difference to epithelial tumors of the liver. The frequency of their occurrence within surgical pathology will increase in the near future, since image analysis and improvement of liver surgery technics raise their recruiting. A total of 1102 primary liver tumors were evaluated from the files of this laboratory between 1981 and 1993, reclassified histologically and in cases of mesenchymal tumors compared with clinical data and course. 208/1102 (19%) mesenchymal tumors were revealed. When 177 cavernous hemangiomas were omitted for its choristomatous character and unproblematically diagnostic approach, a substantial group of 31/1102 (3%) mesenchymal tumors does remain. These were classified as: epithelioid hemangioendotheliomas (EHE) (8/31), angiosarcomas (7/31) infantile hemangioendotheliomas (5/31), mesenchymal hamartomas (5/31), angiomyolipomas (3/31), malignant mesenchymomas (2/31) and schwannoma (1/31). Among other misdiagnoses, 3 of hemangiopericytoma are remarkable, since they had to be reclassified as metastases from adult granulosa cell tumor of the ovary and meningeoma respectively. The histological distinction of EHE's is discussed versus angiosarcoma, since therapy and prognosis are different. These results reconfirm that mesenchymal neoplasms of the liver in adults are usually angiomatous differentiated. Diagnostic approach to probably mesenchymal derived masses of the liver does often request additional information from immunostaining and image analysis, especially when based on needle biopsies. Metastases are to be considered in this procedure. Primary pericytomas were not reconfirmed among this total of 1102 primary liver tumors.