Oral Communications: Liver Tumors

Oral Communications: Liver Tumors

184 . Abstracts Oral Communications: Liver Tumors 9 Hepatocellular Regenerative Nodules, Adenomas, and Carcinomas H.-W. Altmann Wiirzburg, BRD In th...

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184 . Abstracts

Oral Communications: Liver Tumors

9 Hepatocellular Regenerative Nodules, Adenomas, and Carcinomas H.-W. Altmann Wiirzburg, BRD In the non-cirrhotic liver there are, in principle, three sorts of hepatocellular noduli: Regenerative nodules, adenomas and carcinomas. As a rule, they differ histologically clearly from another, but transitio~l (intermediate) forms do occur, especially between adenomas and carcInomas. Regenerative nodules are the manifestation of circu~scribed hyperplasia as a reaction on a preceding cell loss. They COnsist of mostly diploid - regular hypatocytes. Opposite to them there are the more or less autonomous neoformations, which are subdivided in adenomas and carcinomas. Their cells differ increasingly from normal hepatocytes. Differences in appearance and arrangement of the cells and in the ~ontent of connective tissue determine the subtype of hepatocellular carCllloma. The so called focal nodular hyperplasia occupies a special position, whose peculiarity is not clearly understood so far. But it seems to consist in a combination of regenerative and autonomous processes, whereby the one or the other can be in the foreground. In this lesion neoductuli of hepatocellular origin are an important component, demonstr~ting the metaplastic potentialities of (the common) liver cells, still more impressively documented in adult hepatoblastomas.

11 MESENCHYMAL TUMORS OF THE LIVER P. Flemming (a.G.), and A. Georgii Pathologisches Institut, Medizinische Hochschule Hannover, Hannover, BRD Background: Primary mesenchymal tumors of the liver are not very frequent. Therefore, collections of well investigated liver tumors should be analyzed to obtain more experience in this category, which will be helpful for improving the histopathological diagnostics from needle punction biopsies. Methods: 1.102 primary tumors of the liver were collected from 1981 until 12/1993 as surgical specimens either from resection or from explantation of the liver. These cases were investigated including immunostaining and reclassified by a panel of 3 histopathologists. Results: 31/1.102 mesenchymal tumors were revealed (not regarding 177 cavernous hemangiomas). These 31 tumors were classified as: epithelioid hemangioendotheliomas (8/31), angiosarcomas (7/31), infantile hemangioendotheliomas (5/31), mesenchymal hamartomas (5/31), angiomyelolipomas (3/31), malignant mesenchymomas (2/31), schwannomas (1/31), and hemangiopericytomas (0/31). Among other misdiagnoses, 4 of hemangiopericytoma are remarkable, since 3 of them were revealed to be metastases of granulosa cell tumors from the ovaries, confirmed by immunostaining. The fourth case turned out to be a metastasis of a hemangiopericytic meningeoma compared with the primary. Conclusions: Primary hemangiopericytoma of the liver seems to be a very rare entity, since it does not occur among over 1,000 surgically removed primary liver tumors. These results reconfirm that angiomatous tumors represent the largest category among primary liver tumors. The distinction between endothelioma and angiosarcoma is important, since treatment and prognosis are different. Solid, non-angiomatous mesenchymal tumors of the liver should be diagnosed with caution, and metastases should always be considered differentialdiagnostically in- adult patients.

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PROGNOSTIC FACTORS OF HEPATOCELLULAR CARCINOMA Christian Wittekind Pathologisches Institut der Universitat, Abteilung fiir Pathologie in der Chirurgischen Klinik, KrankenhausstraBe 12,91054 ERLANGEN Abstract Long-term survival and cure of patients with hepatocellular carcinoma (HCC) can be expected only after resection or hepatectomy followed by transplantation. Thus, prognosis primarily depends on the possibility of resective surgery, which is determined predominantly by anatomic extent of disease. This survey deals with factors that become effective after resection or transplantation and that have prognostic significance in univariate or multivariate analyses. Several studies have shown that resection for cure (R classification) and anatomical extent of the tumors (TNM) were the most important prognostic factors. Prognostic factors other than TNM and R can be grouped into clinical findings and pathological features. As to clinical findings, performance status is an important prognostic factor in one multi variate analysis which showed also prognostic effects of prothrombin time and elevated levels of serum calcium. The effects of other factors as age, sex, tumor site, and hepatomegaly on prognosis were discussed controversially. As might be expected, studies on pathological factors yielded different results. Histological grade had an influence in one study, but not in another. Histological type and coexisting cirrhosis were important in multivariate analyses only in resected patients. The majority of factors (capsule formation, dysplasia of adjacent liver tissue, mitotic activity, bile production) were only investigated in univariate analyses.There are only few studies evaluating the prognostic importance of molecular pathology factors. None of them has shown convincing evidence that these parameters may give information more important than TNM and R classification. The prognostic importance of TNM for patients not treated by resective surgery is emphasized in many studies. Ascites, toxic syndrome, and laboratory variables as bilirubin, blood urea nitrogen, and serum albumin were independent predictors of survival.

DIVERGENT EXPRESSION OF CD34 IN HEPATIC HEMANGIOSARCOMAS Gabriele Kohler, H.E. Schaefer Pathologisches Institut der Universitat Freiburg Aims: Hepatic angiosarcomas form a heterogeneous group of soft tissue tumors, which stimulated multiple attempts for subclassification. With regard to the fact, that there is a clear divergent expression of the transmembrane protein CD34 in sinusoidal endothelia (CD34 negative) and all other endothelial cells (CD34 positive) we investigated the expression of this antigen on hepatic hemangiosarcomas in comparison with angiosarcomas of other organs. Methods: For the immunohistochemical study we used the CD34 specific monoclonal antibody QBENDlO (Imrnunotech) on formalin-fixed paraffin-embedded tissue. Hemangiosarcomas were obtained from surgical biopsies and autopsies. Results: There is a divergent expression of CD34 with one group of tumors reacting completJy negative for CD34, another group displaying an intense positive reaction which is comparable to the reaction pattern seen in benign angiomas and the majority of malignant hemangiosarcomas. Conclusion: According to these results two different types of angiosarcomas can be discriminated on the basis of their CD34 expression. This clear divergency introduces a new criterium into the diverse attempts to subclassify the heterogeneous family of hepatic hemangiosarcomas. Similar CD34 negative angiosarcomas can be found in other organs in particular in the spleen. It can be supposed that CD34 negative angiosarcomas are derived from the sinusoidal type of endothelia.

Abstracts· 185

13 COMMENTS ON THE HISTOGENESIS OF HEPATOBLASTOMA. ULTRASTRUCTURAL, IMMUNOELECTRON-MICROSCOPIC AND IMMUNOHISTOCHEMICAL FINDINGS

15 TRANSFORMING GROWTH FACTOR B1 (TGFB1) IS DIFFERENTIALLY EXPRESSED IN LIVER TUMORS.

P. Ruck (a. G), J-e. Xiao (a. G), E. Kaiserling Institut fur Pathologie, Universitat Tiibingen, Tiibingen, Germany

M. Vogelbruch (a.G.), A. Wellmann* (a.G.), H. Maschek, M.K. Schaefer** (a.G.), P. Flemming (a.G.), A. Georgii Pathologisches Institut, Medizinische Hochschule Hannover, Hannover, BRD; * Laboratory of Pathology, National Cancer Institute, NIH, Bethesda, U.S.A.; ** Institut fur Anatomie, Universitat Mainz, BRD

Aims: The histogenesis of hepatoblastoma (HB), the most common malignant hepatic tumour of childhood, has not yet been established. Because the multidirectional spectrum of differentiation of this tumour suggests that it derives from a pluripotent stem cell, this study was undertaken to investigate HB for the presence of cells with the features of hepatic stem cells. Methods: Seven HB of various subtypes were investigated by conventional electron microscopy, and immunoelectron microscopy and immunohistochemistry with antibodies against various cytokeratins (CK) Results: Small epithelial cells (SEC) were found in the HB that correspond to the oval cells of the rat and the "small cells" seen in cholestatic liver diseases in man: they were oval and 8-15 !lm long, contained intercellular junctions and numerous tonofilament bundles and exhibited a bile-duct type CK profile (reactivity for CK nos. 7, 8, 18 and 19). These cells were found in very small numbers in fetal HB and moderate numbers in embryonal HB. In small cell HB, nearly all the tumour cells exhibited SEC-like ultrastructural features and a corresponding CK profile. Conclusions: SEC with the features of hepatic stem cells are detectable in HB. Their numbers vary according to the subtype, reflecting the differing degrees of differentiation of the various subtypes consistent with the theory propounded in the literature that embryonal and, with further differentiation, fetal tumour cells derive from precursor small cells. The findings strongly suggest that HB derives from a pluripotent, probably entodermal or even less committed stem cell.

Aims: There is controversy regarding the role of the multifunctional growth factor TGF~1 and the closely related, functionally indistinguishable TGF~2 in hepatocarcinogenesis (1, 2, 3). To further eval uate the express ion of TGFB 1 in different malignant and benign liver tumors, the following study was conducted. Methods: Using a monoclonal anti-TGF~1 antibody (clone TB21, ANTIGENIX AMERICA, U.S.A.), the distribution and amount of TGF~1 was determined in formalin fixed, paraffin embedded sections of 50 hepatocellular carcinomas (HCC), 30 cholangiocellular carcinomas (CCC), 10 hepatocellular adenomas (HCA), 10 focal nodular hyperplasias (FNH), and 20 normal livers (NL). Results: All NL were weakly positive for TGF~1, predominantly in mesenchymal cells. In comparison, TGF~1 was less and only focally expressed in 46/50 HCC and in 25/30 CCC. 9/10 FNH and all HCA showed a stronger staining than the NL cases. There are first results; blotting and in-situ gene hybridizations are in progress and will be presented at the Meeting. Conclusions: The expression of TGF~1 is strikingly lower in HCC and CCC than in NL and benign liver tumors. These results strongly suggest that TGF~1 down-regulation may be an important step in hepatocarcinogenesis. Additionally, determining the expression of TGF~1 may be useful in distinguishing HCC from benign hepatiC lesions when such a distinction is not possible on morphologic grounds alone. References: 1. Braun et aI., Cell Growth Differ 1990, 1 : 103; 2. Ito et aI., Cancer Res 1991, 51 : 4080; 3. Lee et al., Proc Am Assoc Cancer Res 1993, 34 : 146

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PATHOGENETIC ROLE OF HEPATITIS B VIRUS IN LIVER CELL CARCINOMAS OF WESTERN EUROPEAN PATIENTS

PRIMARY AND SECONDARY MALIGNANCIES OF THE LIVER IN CYTOLOGY, BIOPSY AND AUTOPSY MATERIAL: FREQUENCY AND DIFFERENTIAL DIAGNOSTIC PROBLEMS H. NIZZE, R. HEBECKER (a. G.), H.-P. PUTZKE, M. BARTEN, ANDREA KACKENMEISTER (a. G.) Institute of Pathology, University of Rostock Aims: A study was made to evaluate differences in frequency and differential diagnosis of primary and secondary malignant liver tumours in varying morphologic materials. Special regard was given to indicate the primary tumour of liver metastases. CytOlogy. Fine needle aspirations of 58 patients with clinically suspected liver cancer were examined from 1980 to 1994. 11 tumours were classified as hepatocellular carcinoma; 28 liver metastases were found (13 with known, 15 with unknown primary tumour); in 9 cases only a differential diagnosis between primary and secondary tumour was possible; 10 cases showed irrelevant findings. Biopsy. In the same period, 187 malignant liver tumour biopsies were histologically stUdied. 21 hepatocellular and 3 cholangiocellular carcinomas were diagnosed; 151 liver metastases were found (101 with known, 50 with unknown primary tumour); in 12 cases only a differential diagnosis could be given between primary carcinoma and metastasis. The immunohistologic differentiation of 106 adenocarcinomas in liver biopsies is stressed. Autopsy. In a total of 6.716 necropsies from 1985 to 1993, 2.579 cancer cases were found. Liver involvement was observed in 1.050 cases; 91 of them had primary malignant liver tumours, 959 showed secondary hepatic malignancies classified and presented in detail. Conclusions: At autopsy, the liver is involved in 41 % of all malignoma cases, with a primary/ secondary tumour ratio of 1:10. This ratio shifts to 1:6 in biopsy and 1:2.5 in cytology material. In 6 % of biopsy and in 16 % of cytology cases, only a tumour differential diagnosis was possible.

G. HERRMANN, CAROLA GREGEL (a.G.), K. HUBNER Senckenbergisches Zentrum der Pathologie, lohann-WolfgangGoethe-Universitat, Frankfurt am Main, BRD Aims Studies concerning the demonstration ofHBV material in sufficient numbers ofliver cell carcinomas (LCC) from western European patients in order to establish a pathogenetic relationship of HBV infection and LCC are lacking in contrast to the situation in Asiatic patients. Methods: Tumor tissue (n=338) and corresponding liver parenchyma (n=276) ofLCC patients was studied with immunohistochemical methods (IHC) for the expression of HBs (7 monoclonal and 2 polyclonal antibodies), HBc, HBe, HBx, and preS antigens. Detection of HBVDNA was carried out with in situ hybridization (ISH) employing digoxigenin-labeled DNA probes. Furthermore, PCR was done for a fragment of the X-ORF (1542+, 1746-). The study included 31 tumors from Asiatic patients. Tumors from the European patients were fibrolamellar carcinomas (FLC; n=8), hepatocellular (HCC; n=260), mixed hepatocellular/cholangiocellular (HeC/eCC; n=23), and pure cholangiocellular carcinomas (CCC; n=16). Results: Of the Asiatic cases, 56.5% contained HBs in the liver parenchyma and 64.5% within the tumor, of the European cases 21.7% and 29.6%, respectively HBc, HBe, and preS antigens were found only in few cases. Positive rates for ISH were 82.6% and 87.1 % for Asiatic, and 45 J% and 51.7% for European cases, respectively Altogether, 93.6% of the Asiatic and 64.2% of the European patients were positive for HBV with IHe or ISH. HCC/CCC and CCC showed slightly lower positive rates compared with HCe. More than 90% of the cases had HBx in liver or tumor tissue. Despite problems with DNA extraction from paraffin material, PCR revealed calculated positive rates of 73.2% for liver and 90.1 % for tumor tissue irrespective of patients descent and tumor type Conclusions: HBV seems to represent a pathogenetic factor for LCC in western European patients irrespective of the tumor type. Obviously, HBx and HBs are especially important in this respect. The existence of the "mixed tumors" HCC/CCC as well as the frequent HBV-positivity of HCC/CCC and CCC document that CCC represents a special differentiation form of LCe.