Virchows Archiv最新文献

Since their initial description in 1948, Spitz tumours have always been a challenge in the field of dermatopathology and paediatric pathology. Advances in molecular pathology have confirmed they are associated with specific anomalies, mainly gene fusions. They display a wide range of clinical presentations and histological subtypes. Most cases are Spitz nevi and very few lesions match the criteria to be diagnosed as atypical Spitz tumours. Even fewer are labelled as Spitz melanomas. Follow-up studies of genetically characterized cases have repeatedly confirmed that, even if the regional lymph node is involved, the overall outcome remains favourable. The aims of this review are to cover the variety of morphological presentations of Spitz tumours and illustrate the most rare subtypes. When possible, we have pointed out the potential trends between some unusual morphological features and the frequently associated genetic drivers. Spitz tumours have many differential diagnoses, the main being superficial spreading melanoma, with overlapping morphological features in early lesions. Essential clues to discriminate Spitz from mimickers have been listed and illustrated.

The management of thyroid nodules is guided by the cytological classification provided by The Bethesda System for Reporting Thyroid Cytology. Notably, the biology of thyroid tumors in pediatric patients differs from that in adults, and there is limited research focused on pediatric cases. This study aimed to assess the effectiveness of the Bethesda system in pediatric patients treated at the largest tertiary pediatric thyroid center in Poland between 2015 and 2023. A retrospective analysis was conducted on 566 patients with thyroid nodules, of whom 555 underwent fine-needle aspiration biopsy (FNAB). A total of 217 patients underwent thyroid surgery. Of these, 206 had previously undergone FNAB with cytological evaluation at our center, while 11 patients underwent thyroid surgery due to a RET mutation or the need for an extended procedure. The initial FNAB results showed distribution across Bethesda categories as follows: 7.6% for category I, 54.6% for category II, 20.9% for category III, 4.1% for category IV, 7.6% for category V, and 5.6% for category VI. Among patients who underwent surgery, the distribution of Bethesda categories I through VI was 2.9%, 25.2%, 29.1%, 8.3%, 19.4%, and 15%, respectively. The risk of malignancy (ROM) from the initial FNAB was estimated at 33.3%, 11.5%, 22.2%, 4.8%, 84.4%, and 96.8% for Bethesda categories I through VI, respectively. In patients with autoimmune thyroiditis (AIT), the ROM was higher than in non-AIT patients for Bethesda categories I through IV, while it was lower in category VI. The sensitivity for detecting non-benign neoplasms across Bethesda categories III through VI was approximately 86% in both AIT and non-AIT patients. However, for papillary thyroid carcinoma, sensitivity in Bethesda categories V and VI was 86% in non-AIT patients but decreased to 61.5% in AIT patients. These findings emphasize the importance of considering surgical intervention in pediatric patients with Bethesda III-VI cytology, particularly in those with AIT.

Architectural distortion and basal plasmacytosis are the most widely recognized histologic features of chronic ileal inflammation. However, these features might be difficult to assess in small, poorly oriented, or superficial biopsies. Additional features of chronic mucosal damage, including pseudopyloric or pseudofoveolar metaplasia and Paneth cell hyperplasia, have been less commonly reported, and their broader appreciation could facilitate the diagnosis of chronic ileal inflammatory conditions. The prevalence of gastric-like (pseudopyloric and pseudofoveolar) metaplasia and Paneth cell hyperplasia was evaluated in 102 ileal biopsies obtained from patients with Crohn's disease (n = 47), ulcerative colitis with endoscopically normal ileum (n = 20) or with backwash ileitis (n = 20), and nonsteroidal anti-inflammatory drugs- (NSAIDs-) induced ileitis (n = 15). Gastric-like metaplasia was identified in 23% of CD and 13% of NSAID-induced ileitis cases, whereas it was absent among all ulcerative colitis cases. Pseudopyloric metaplasia, pseudofoveolar metaplasia, or a combination of both was documented in 13%, 2%, and 9% of Crohn's disease cases, respectively. NSAID-associated cases showed only pseudopyloric metaplasia. Paneth cell hyperplasia was detected in 43% of Crohn's disease cases, 13% of NSAID-induced ileitis cases, and 5% of backwash ileitis cases. Accordingly, pseudofoveolar metaplasia, pseudopyloric metaplasia, and Paneth cell hyperplasia are not uncommon in conditions causing chronic ileal inflammation. They are most frequently detected in Crohn's disease, but may also be present in NSAID-induced ileitis, whereas they are significantly less common in backwash ileitis and absent in normal ileum. Given the surface localization of pseudofoveolar metaplasia, its identification can be particularly helpful when dealing with poorly oriented or superficial samples.

The advent of "omics" technologies for high-depth tumor profiling has provided new information regarding cancer heterogeneity. However, a bulk omics profile can only partially reproduce tumor complexity, and it does not meet the preferences of pathologists used to perform an in situ assessment of marker expression, for instance, with immunohistochemistry. The NanoString GeoMx® Digital Spatial Profiler (DSP) is a platform for morphology-guided multiplex profiling of tissue slides, which allows the digital quantification of target analytes in different neoplastic settings. To illustrate the feasibility and opportunities offered by DSP from a pathologist's perspective, we applied DSP in three different representative neoplastic settings: breast carcinoma, thyroid anaplastic carcinoma, and biphasic mesothelioma. Because of the perfect overlap between the hematoxylin-eosin-stained slide and the GeoMx areas of interest, in breast carcinoma, two different antibodies allowed the distinction of the tumor cells from the surrounding tumor microenvironment. In biphasic mesothelioma, we could distinguish the epithelioid from the sarcomatoid neoplastic component, and in the thyroid, we easily separated the anaplastic areas from the well-differentiated carcinoma. DSP is a promising tool that combines traditional histological evaluation, allowing spatial assessment of a tumor and its surroundings, and innovative in situ digital profiling. Pathologists should not miss the opportunity to combine morphological and genomic analyses and be at the forefront of investigating the progression of dysplasia/neoplasia, low-grade or high-grade, epithelial/mesenchymal, and, more in general, overcoming the concept of in situ vs. bulk genomic methods.

We report a case of a 65-year-old man with a 1.0-cm mass in the left main bronchus, exhibiting overlapping morphological, immunohistochemical, and genetic features with both pancreatic intraductal papillary mucinous neoplasm (IPMN) with associated invasive carcinoma and salivary gland IPMN. Based on its close proximity to the bronchial submucosal glands and the expression of NKX3.1 (an established immunohistochemical marker for mucinous acinar cells of the minor salivary glands), we propose that the tumor originates from the mucinous acinar cells of the bronchial salivary gland. Therefore, we suggest naming it bronchial salivary gland-type mucinous adenocarcinoma. Interestingly, a GNAS mutation, known as a highly specific marker for pancreatic IPMN, was detected by next-generation sequencing in our case. We believe that this tumor may represent a novel lung cancer entity.

Fibroblastic and myofibroblastic neoplasms represent about 12% of pediatric soft tissue tumors. Most of these neoplasms in children are either benign or locally aggressive with rare metastasis, while malignant cases are uncommon. Diagnosing these tumors is challenging due to overlapping morphologies and the limited utility of immunohistochemistry. Advances in molecular techniques, especially RNA sequencing, have improved our understanding of the molecular drivers of these tumors, leading to better classification. Key molecular alterations, such as RTK and MAPK activation, are central in the development of tumors like infantile fibrosarcoma (IFS) and inflammatory myofibroblastic tumors (IMT). The identification of alternative fusions in IFS and IMT underscores the importance of an integrated diagnostic approach. Furthermore, new RTK-driven lesions, now included in the WHO's "NTRK-rearranged mesenchymal neoplasms", have been identified. This review provides an update on recent findings in RTK-driven myofibroblastic tumors and highlights novel entities still in need of classification.

Pediatric-type follicular lymphoma (PTFL) and pediatric nodal marginal zone lymphoma (PNMZL) are two rare indolent B-cell lymphomas with overlapping features. Recently, cases showing hybridizing features of PTFL and PNMZL have been reported. Herein, we retrospectively analyzed the clinicopathologic features of 59 patients, including 39 with PTFL, 5 with PNMZL, and 15 with mixed-type tumors (MTT). And next-generation sequencing analysis was performed on 3 PTFL, 2 PNMZL, and 2 MTT cases. In addition, previously published mutational data of 96 PTFLs, 25 PNMZLs, and 46 MTTs were also analyzed. There were 52 male and 7 female patients, with a median age of 17 years. Most patients (96.6%) had lymph node involvement in the head and neck region and were diagnosed with stage I disease. Among the 50 patients (85%) with telephone follow-up, 44 (88%) adopted a watch-and-wait strategy after surgical resection of the lesions. Only one PTFL patient experienced a relapse 6 months after diagnosis. Microscopically, not only the MTT cases showed a composite form of enlarged follicles and interfollicular lymphocytic proliferation producing a progressively transformed germinal center (PTGC) pattern, but also focal follicles with a PTGC-like pattern were observed in PTFL cases. Genetically, the most frequently mutated genes were TNFRSF14 (in 3 PTFLs and 2 MTTs), MAP2K1 (in 2 PTFLs, 1 PNMZL and 1 MTT), and IRF8 (in 2 MTTs and 1 PNMZL). Based on the similar or overlapping clinical, pathologic, and genetic features, PTFL and PNMZL are likely to represent two different histologic patterns of the same disease.

Thyroid transcription factor 1 (TTF-1) immunohistochemistry (IHC) is routinely used for the distinction of primary pulmonary adenocarcinomas. However, TTF-1 can also occur in other malignancies. A tissue microarray containing 17,772 samples from 152 different tumor types was analyzed. Napsin-A, CK20, SATB2, FABP1, and Villin-1 IHC data were available from previous studies. TTF-1 staining was seen in 82 of 152 tumor categories including thyroidal cancers (19-100%), adenocarcinomas (94%), neuroendocrine tumors (67%) of the lung, small cell neuroendocrine carcinomas (71-80%), mesenchymal tumors (up to 42%), and thymomas (39%). Comparative analysis of TTF-1 and Napsin-A revealed a sensitivity/specificity of 94%/86% (TTF-1), 87%/98% (Napsin-A), and 85%/99.1% (TTF-1 and Napsin-A) for the distinction of pulmonary adenocarcinomas. Combined analysis of TTF-1 and enteric markers revealed a positivity for TTF-1 and at least one enteric marker in 22% of pulmonary adenocarcinomas but also a TTF-1 positivity in 6% of colorectal, 2% of pancreatic, and 3% of gastric adenocarcinomas. TTF-1 is a marker of high sensitivity but insufficient specificity for pulmonary adenocarcinomas. A small fraction of TTF-1-positive gastrointestinal adenocarcinomas represents a pitfall mimicking enteric-type pulmonary adenocarcinoma. Combined analysis of TTF-1 and Napsin-A improves the specificity of pulmonary adenocarcinoma diagnosis.

EIF1AX mutation has been identified as a driver mutation for papillary thyroid carcinoma (PTC) by The Cancer Genome Atlas (TCGA) study. Subsequent studies confirmed this mutation in PTC and Anaplastic Thyroid Carcinoma (ATC) but also reported EIF1AX mutation in Follicular nodular disease (FND) and benign thyroid nodules. In this study, we review thyroid nodules with EIF1AX mutation from two institutions: a tertiary care hospital (YNHH, n = 22) and a major cancer referral center (MSKCC, n = 34) and report the varying histomorphology in the context of additional genetic abnormalities and institutional practices. Pathology diagnoses were reviewed according to the WHO 5th edition and correlated with the type of EIF1AX mutation and additional concurrent molecular alterations, if any. Most cases were splice site type mutations. Cases consisted of 9 FND, 7 follicular (FA) or oncocytic adenomas (OA), 2 non-invasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP) and 38 follicular-cell derived thyroid carcinomas. Of 8 cases with isolated EIF1AX mutation, 7 were FND, FA or OA (88%) and one was an oncocytic carcinoma (12%). Of 12 cases with EIF1AX and one additional molecular alteration, 9 (75%) were FND, FA or OA, 2 (17%) were NIFTPs and one (8%) was a poorly differentiated thyroid carcinoma. All 36 cases with EIF1AX mutation and $\ge 2$ molecular alterations were malignant (100%) and included TP53 and TERT promoter mutations associated with ATC (n = 8) and high-grade follicular cell-derived non-anaplastic carcinoma (HGC, n = 2). Isolated EIF1AX mutation was noted only in thyroid nodules seen at YNHH and were predominantly encountered in benign thyroid nodules including FND. Accumulation of additional genetic abnormalities appears to be progressively associated with malignant tumors.