Pathologie (Heidelberg, Germany)最新文献

The 9th TNM Classification for Lung Cancer, based on IASLC data, was published in January 2025. This edition is currently available online as a download or printed manual in English ( www.iaslc.org/research-education/publications-resources-guidelines/staging-manual-thoracic-oncology-3rd-edition ). Key changes include the subclassification of pN2 into pN2a/b and M1c into M1c1/2, leading to improved prognostic differentiation and reclassification of individual TN combinations into UICC stages. The T-category remains formally unchanged but has been anatomically refined. A survey of 18 pathology institutes conducted by the Thoracic Pathology Working Group revealed that 83% use TNM 8 and only 22% already use TNM 9; 39% subclassify pN2 and 67% document pleural status (PL0-3). The Thoracic Pathology Working Group recommends immediate structured implementation of TNM 9, in particular the N2 subclassification, as well as dual documentation of TNM 8 and 9 during the transition phase until January 2026. Formal implementation in clinical practice is planned for this date. R0(un) should be commented on optionally, and the pleural status should be specified in detail (PL0-3).

The differential diagnosis of intrahepatic cholangiocarcinomas (iCCA), hepatocellular carcinomas (HCC) and liver metastases of extrahepatic primary tumours is crucial but may be challenging. N‑cadherin, a transmembrane glycoprotein of adherens junctions, is typical for neural and mesenchymal cells, whereas most epithelia and carcinomas derived therefrom are negative for N‑cadherin. However, hepatocytes and cholangiocytes, along with HCC and iCCA, are exceptions as they exhibit expression of N‑cadherin, making this a valuable immunohistochemical marker. We previously showed in a study on 3359 tumours that N‑cadherin positivity reliably differentiates primary liver carcinomas from liver metastases of extrahepatic carcinomas. N‑cadherin therefore complements the immunohistochemical panel in the differential diagnosis of carcinoma of unknown primary (CUP).

Liver biopsies in unclear hepatitis are required to assess etiology together with the clinico-serological findings to differentiate comorbidities. In addition, inflammatory activity should be graded, extent of necrosis estimated, and the stage of fibrosis determined in order to estimate pre-existing parenchymal damage. In liver biopsies from patients with acute liver failure, drug-induced liver injury, most often in idiosyncrasy is most common. While a liver biopsy is required for the diagnosis of autoimmune hepatitis, the diagnosis of viral hepatitis A-D is usually made clinically and serologically. Yet, hepatitis E is often underestimated: in addition to acute hepatitis in immunocompetent patients, hepatitis E-virus (HEV) infection may also manifest with a fulminant course in patients with pre-existing liver cirrhosis and follow a chronic course in immunocompromised patients.

Hepatocellular adenomas (HCAs) are rare benign hepatocellular neoplasia that typically occur in a non-cirrhotic liver in young women on contraceptive therapy or in metabolic liver disease. HCAs may be subtyped radiologically and histologically, controlled under discontinuation of contraceptives, and resected in the case of malignant transformation potential or an HCA size of more than 5 cm.Histologically, HCAs present as well-differentiated hepatocellular neoplasms, which in contrast to focal nodular hyperplasia (FNH) lack portal tract-like structures. Prognostically relevant morphomolecular HCA subtypes have been described. HNF1A-inactivated HCAs often show a prominent steatosis and loss of L‑FABP. Inflammatory HCAs (IHCAs) are characterized morphologically by a prominent inflammatory infiltrate and ectatic sinusoids and show a positive immune reaction with antibodies against serum amyloid A and CRP. In contrast to other HCAs, β‑catenin-activated HCAs due to CTNNB1 mutation in exon 3 occur relatively more frequently in men (for example after intake of anabolic steroids) and have a significantly increased risk of transformation in a hepatocellular carcinoma (HCC) in comparison to CTNNB1 mutations in exons 7 and 8. CTNNB1 mutations may also occur in IHCAs (b-IHCA). Sonic hedgehog-activated HCAs show increased ASS1 expression and have a high risk of rupture and bleeding.Concerning differential diagnosis, it is important to distinguish HCAs from FNH, which cover a clinically similar patient group, and from highly differentiated HCC, which occur more frequently in men at an increased patient age and in chronic liver disease.

Alveolar and cystic echinococcosis are rare zoonotic diseases caused by the larval stages of E. multilocularis and E. granulosus. Due to their tumour-like growth, it is often necessary to differentiate them from neoplasms of the liver both macroscopically and histologically. The larval stage is localized predominantly, but not exclusively, in the liver and is characterized for Echinococcus multilocularis macroscopically by a necrotic, "bread-like" ill-defined lesion with intermingled microcysts; in contrast, lesions of E. granulosus show well-defined "noodle- and grape-like" macrocystic lesions. Histologically, the lesions of E. multilocularis are characterized by a tubular, infiltrative growth accompanied by extensive necrosis and a rim composed of epithelioid cells, a fibrotic zone, and a lymphoplasmacytic infiltrate at the transition to non-infected liver tissue. In E. granulosus the necrotic area is less pronounced, without tubular growth and is followed by a rim area identical to lesions caused by E. multilocularis, with the fibrosis zone being significantly wider. The identification of the strongly PAS-positive fragmented lamellar body in the necrotic area is essential. This structure is narrow and fragmented in the larval stage of E. multilocularis, whereas it is distinctly wider in E. granulosus. The positive immunohistochemical staining with monoclonal antibody (mAb) EmG3 confirms the diagnosis of echinococcosis. Regarding the differential diagnosis by immunohistochemistry, the laminated layer of E. multilocularis stains positive with the monoclonal antibodies (mAb) EmG3 and Em2G11, whereas the laminated layer of E. granulosus sensu is only positive with mAb EmG3. Immunohistochemically, fragments of the lamellar body can be detected in the germinal centres of draining lymph nodes infections caused by E. multilocularis and E. granulosus (small particles of E. multilocularis, SPEMs; and small particles of E. granulosus, SPEGs), thus allowing the diagnosis even on small biopsies without lamellar body.

The grossing and reporting of radical prostatectomy specimens are key issues in pathology. Consensus conferences have defined clear guidelines for UICC/TNM-relevant parameters, while the extent of embedding remains controversial. Various embedding protocols, such as the Bonn protocol, enable efficient processing with consistent diagnostic significance. The increasing use of standardized diagnostic schemes, such as those developed by the International Collaboration on Cancer Reporting (ICCR), can ensure (international) comparability of diagnoses. This paper explains the criteria for embedding and reporting with a particular focus on prognostically relevant findings such as the differentiation between pT2 and pT3 tumors.

Despite advances in imaging diagnostics, the histological confirmation of suspected carcinoma through prostate core needle biopsy remains essential for treatment planning. Diagnosis is based on established morphological criteria such as architectural disturbances, cellular atypia, and loss of the basal cell layer. In addition to the most common acinar prostate carcinoma, various subtypes and rare histological patterns exist, which must be differentiated from benign mimickers. Immunohistochemical methods support diagnostic accuracy but should be carefully interpreted in the context of morphology. Tumor extent in core biopsy specimens should preferably be reported in millimeters. Diagnostic uncertainties can be coded as atypical small acinar proliferation (ASAP) or atypical intraductal proliferation (AIP) to facilitate appropriate clinical interpretation.

Vascular neoplasms of the liver encompass a spectrum ranging from the common benign hemangiomas to the very rare malignant vascular neoplasms, namely epithelioid hemangioendotheliomas (EHE) and angiosarcomas. Despite their high prevalence, hemangiomas are rarely biopsied or resected-typically only in cases with atypical imaging features or when large size raises concern for rupture. In this overview, we place particular emphasis on the newly described entity known as hepatic small vessel neoplasm (HSVN). Epithelioid hemangioendotheliomas and angiosarcomas, due to their rarity and several diagnostic pitfalls, can pose significant diagnostic challenges in histopathology. These pitfalls will be specifically addressed here.