Pathologie (Heidelberg, Germany)最新文献

Lymphocyterich lesions account for the majority of relevant differential diagnoses in the anterior mediastinum and include non-neoplastic and neoplastic entities. With only 10-15% of cases, lymphomas account for a relatively small proportion of these. A systematic approach and consideration of epidemiological and clinical background information are crucial for a correct diagnosis, particularly in the case of small biopsies. A few entities dominate among mediastinal lymphomas: nodular sclerosing Hodgkin lymphoma (NSCHL) is the most common form, accounting for 50-70% of cases, followed by primary mediastinal large B‑cell lymphoma (PMBL) and T‑lymphoblastic lymphoma (T-LBL). Epidemiologically, all of these tumors occur predominantly in children and young adults; all other lymphomas are rare and mostly affect older patients. In this context, typical practical diagnostic challenges include the distinction of B‑cell lymphomas from other B‑cell-dominated lesions, the distinction of T‑LBL from thymomas, the subtyping of sclerotic lymphomas (NSCHL, PMBL, gray zone lymphomas) and their separation from other sclerosing processes. This overview focuses on the discussion of these practice-relevant diagnostic problems.

In 2025, the S2k guideline on early pregnancy loss in the first trimester was published. This guideline covers disrupted early pregnancy and pregnancies of unclear localization resulting in miscarriage, their etiology and risk factors, clinical diagnosis and patient care, as well as pathomorphological diagnostic criteria and recommendations for the macroscopic handling of the abortion tissue and its microscopic processing. In addition to possible causes, the aspects that are important for pathomorphological diagnosis are presented, and the diagnostic criteria mentioned in the guideline are summarized in tables and illustrated with images.

Lymphomas in children and adolescents account for only 1-2% of all lymphomas and differ markedly from adult cases in terms of subtype distribution, molecular profiles, and prognosis. This review summarizes current advances in the classification, biology, and diagnosis of pediatric lymphomas, with a focus on rare indolent entities and reactive, lymphoma-mimicking lesions.In addition to the more common entities such as Burkitt lymphoma, lymphoblastic lymphoma (particularly T‑lymphoblastic lymphoma), Hodgkin lymphoma, and ALK-positive anaplastic large cell lymphoma, children may present with rare indolent subtypes including pediatric type follicular lymphoma (PTFL), pediatric nodal marginal zone lymphoma (PNMZL), and testicular follicular lymphoma variants, all of which are associated with excellent prognosis. Aggressive subtypes comprise IRF4-rearranged large B‑cell lymphoma (LBCL-IRF4) and high-grade/large B‑cell lymphoma with 11q aberration (HG/LCBL-11q), both also demonstrating favorable outcomes. Particularly challenging in differential diagnosis are reactive lymphoid proliferations such as infectious mononucleosis, Kikuchi-Fujimoto disease, atypical marginal zone hyperplasia, and progressive transformation of germinal centers (PTGC).Pediatric lymphomas represent a heterogeneous group with specific clinical and biological features. Their diagnosis requires careful consideration to accurately distinguish rare indolent entities, recently defined large B‑cell lymphomas, and reactive mimics. Recent classifications, including the newly introduced WHO Classification of Pediatric Tumors, increasingly reflect these unique aspects.

Advanced and widespread molecular techniques have deepened our understanding of mesenchymal lesions, revealing considerable overlap among morphologically defined entities now known to be related to protein kinases (PKs). This paradigm shift is important for understanding oncogenesis and also in terms of treatment options and prognosis. Therefore, it is preferable to stratify these tumors molecularly instead of morphologically, as the different categories have clinical implications. Molecular analyses are an essential and integrated part of the diagnostic workup of tissue specimens, especially those of young patients. Involved PKs range from receptor tyrosine kinases (neurotrophic tyrosine receptor kinase [NTRK]1, 2, 3; anaplastic lymphoma kinase [ALK]; proto-oncogene 1 [ROS1]; proto-oncogene [RET]; and proto-oncogene/hepatocyte growth factor receptor [MET]; etc.) to intracytoplasmic serine/threonine kinases (RAF proteins) activating the same pathways. Morphological patterns vary from infantile fibrosarcoma(-like) to lipofibromatosis(-like), dermatofibrosarcoma protuberans(-like), and malignant peripheral nerve sheath tumor-like. However, there is considerable overlap histopathologically and immunohistochemically. Most of the neoplasms are (myo)fibroblastic in type, consisting of monomorphic cells. A hemangiopericytoma-like vasculature can be a diagnostic clue. The immunophenotype is characterized by variable expression of smooth muscle actin (SMA)/desmin/CD34 or CD34/S100. This review provides updates to understand the currently known spectrum of PK-related lesions, with emphasis on those occurring more rarely, to aid proper diagnoses and treatment. The aim is to contribute to a better holistic classification.

Benign tumours and lesions in the head region in children are rare and can pose a diagnostic challenge. This article presents selected rare benign lesions in the head region in children with the aim of describing the most important morphological and immunohistochemical characteristics that are relevant for diagnosis. The spectrum ranges from phakomatous choristoma, meningothelial hamartoma, dermoid cyst, pilomatrixoma, and juvenile xanthogranuloma to benign vascular lesions.

A two-year-old child was found lifeless in bed after experiencing brief gastrointestinal symptoms.Histological examination revealed no abnormalities, but electron microscopy showed clear atypia of the mitochondria with linear paracrystalline inclusions.Genetic testing revealed variants of unclear significance in the TYMP and AIFM1 genes and a heterozygous pathogenic mutation in the GCDH gene.To date, no clear causality between the mutations found and the mitochondrial morphology can be established, but in vitro experiments show certain analogies to the structural changes in the mitochondria detected here.

Curettages of early pregnancy losses (EPLs) are frequently sent specimens for pathologic anatomic investigation, because about 15% of the clinically diagnosed pregnancies result in a miscarriage. According to recently published German recommendations, every early miscarriage should be investigated morphologically. In a careful macroscopic preparation, the different compartments (decidua, villous tissue, and possibly embryo/fetus) should be identified and submitted for histologic diagnosis. The most important issues for the microscopic investigation are documentation of an intrauterine pregnancy (to rule out extrauterine gravidity), screening for gestational trophoblastic disease, and-if possible-detection of pathologic anatomic visible causal factors for early pregnancy loss. In some instances, especially in the case of repeated spontaneous miscarriage in the first trimester, the supplement of conventional cytogenetic analysis and molecular genetic and molecular pathologic methods may be useful for confirmation of a diagnosis. A standardized procedure for asservation of native trophoblastic tissue should be established in the department. The detection of early complete hydatidiform mole and partial hydatidiform mole is important, since these lesions have a risk for the subsequent development of persisting gestational trophoblastic disease. Histologic characters of sporadic chromosomal aberrations (the most frequent etiology of EPLs) in miscarriage specimens are abnormalities of the villous tissue (trophoblast, stroma, and vessels).Chronic histiocytic intervillositis (CHI), massive perivillous fibrin deposition (MFD), and chronic deciduitis are morphologically defined lesions with partly high recurrence risk. These placental diseases can be causal factors for clinical habitual miscarriage.Although the limitations of the morphologic diagnostic procedure have to be recognized, the standardized pathologic anatomic investigation of miscarriage specimens can render information on the etiology and recurrence risk in some cases of early pregnancy loss.