中华病理学杂志最新文献

Objective: To investigate the clinicopathological characteristics of well-differentiated papillary mesothelial tumor (WDPMT). Methods: Sixteen cases of resected WDPMTs diagnosed at the Affiliated Hospital of Qingdao University, Qingdao, China from 2017 to 2024 were collected and the clinicopathological features were retrospectively analyzed. Results: There were 7 males amd 9 females, with a mean age of 53.8±14.8 years (range, 25-83 years). Tumor size ranged from 3 to 12 mm in maximum diameter. Of the 16 cases, 15 involved the peritoneum and 1 involved the pleura, one of which occurred on the surface of ovary. All cases were incidentally identified during unrelated surgical procedures. Histologically, tumors exhibited arborizing papillary growth patterns and frequently displayed hierarchically branching papilla. Tumor cells showed cuboidal to flattened cell morphology with minimal nuclear atypia. Mitotic figures were not noted in all cases. Entrapped gland-like tumor cell clusters were found in the stroma of tumor papilla in 1 of the 16 cases. Immunohistochemically, the tumor cells expressed mesothelial markers (Calretinin, D2-40, and CK5/6) in all cases, and BAP1 and MTAP were immunoreactive in all tested cases. Fluorescence in situ hybridization revealed no CDKN2A deletions. Conclusions: WDPMT predominantly occurs in the peritoneum and typically demonstrates indolent biological behaviors. It often shows overlapping features with mesothelioma in situ and epithelioid mesothelioma. The hierarchical branching papillae is its diagnostic hallmark, while routine immunohistochemical evaluation of BAP1 and MTAP is also recommended for differential diagnosis of these tumors.

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of primary bladder lymphoma. Methods: A retrospective study was conducted on 23 cases of primary bladder lymphoma diagnosed at Beijing Friendship Hospital of Capital Medical University between February 2010 and April 2024. The clinicopathological data were collected and analyzed, and literature was reviewed. Results: Among the 23 cases, 7 were male and 16 were female, with a male-to-female ratio of 1.0∶2.5. The median age was 65 (58, 71) years, ranged 38-84 years. The main clinical manifestation was painless visible hematuria, followed by frequent urination, urgency, and lower abdominal discomfort. Only one case presented with fever, and all cases primarily presented as bladder masses or lesions. The histological types included 17 cases of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (EMZL), 4 cases of diffuse large B-cell lymphoma (DLBCL), 1 case of ALK-negative anaplastic large cell lymphoma (ALCL), and 1 case of indolent NK-cell lymphoproliferative disease (INKLPD). EMZL exhibited relatively uniform morphology. Among them, 2 cases showed marked plasmacytic differentiation, 1 case had an increased number of large cells, 6 cases had residual germinal centers, and 2 cases presented with lymphoepithelial lesions. All cases demonstrated irregular FDC networks. DLBCL cells were larger in size; 3 cases showed diffuse infiltration, while 1 case had scattered, clustered distribution in a background of small lymphocytes,and with aberrant expression of GATA3. ALCL negative ALCL showed classic anaplastic morphology with "kidney-shaped" nuclei. INKLPD cells were of medium size and irregular in shape, with some cells containing eosinophilic granules in the cytoplasm. EBER in situ hybridization was negative. Conclusions: The primary histological types of bladder lymphoma are EMZL and DLBCL, with occasional cases of T-cell lymphoma and INKLPD. Clinical manifestations lack specificity and may overlap with inflammatory conditions or epithelial tumors. Both clinicians and pathologists should be aware of these rare diseases to facilitate accurate diagnosis and treatment.

Objective: To explore the clinical features, histopathological morphology, and differential diagnosis of lymphoepithelioma-like carcinoma with abnormal expression of follicular dendritic cell markers. Methods: From 2020 to 2021, 4 cases of lymphoepithelioma-like carcinoma with abnormal expression of follicular dendritic cell markers diagnosed in Fujian Cancer Hospital (2 cases) and the Second Affiliated Hospital of Fujian Medical University (2 cases) were collected. Different ancillary procedures such as HE, special stains, immunohistochemistry, and in situ hybridization techniques were used to assess the histopathological features and immunophenotypes. The clinical data were collected and literature was reviewed. Results: All 4 cases of lymphoepithelioma-like carcinoma with abnormal expression of follicular dendritic cell markers were male. They were 32, 45, 67 and 39 years old, respectively. The main clinical manifestations were bloody phlegm, abdominal pain, fatigue and anorexia. The clinical stages at diagnosis were stage Ⅳ (3 cases) and stage Ⅱ (1 case). Cases 2 and 3 had two pathological examinations at different sites, with a total of six pathological examinations. The histomorphology showed singly scattered or nests of tumor cells in a background of abundant small lymphocytes. The tumor cells were enlarged and pleomorphic, some appeared polygonal with inconspicuous cell borders, and they were arranged in a syncytial pattern. There were megakaryocytes, multinucleated tumor cells, and a few spindle-shaped cells seen. Atypical mitosis was commonly noted. By immunohistochemistry, the tumor cells were positive for CKpan(5/6), CK8/18(4/4), CAM5.2(2/5), CK-H(0/4), CK-L(3/4), EMA(4/5), CK5/6(3/6), p63(1/6), p40(1/6), E-cadherin (4/6), SSTR2(6/6), PD-L1(5/5), LCA(0/6), vimentin(5/6), CD2 (6/6), CD23(6/6), CD35(5/6), CXCL-13(4/5) and D2-40(1/5). The Ki-67 proliferative index was 60%-95%. In situ hybridization for EBER were all positive (6/6). Special stain for reticulin showed positive staining surrounding nests of tumor cells. Conclusions: The expression of follicular dendritic cell markers in lymphoepithelioma-like carcinoma is very rare, which may be related to EBV infection. Occasionally, it can overlap with follicular dendritic cell sarcoma by morphology and immunophenotype, which can lead to misdiagnosis. Only by combining clinical information, morphological characteristics and immunophenotype can an appropriate diagnosis be made.

Objective: To investigate the clinicopathological and genetic characteristics of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL). Methods: The forty-two MEITL cases diagnosed in the Department of Pathology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China from 2016 to 2022 was retrospectively analyzed. Clinical data were collected, and follow-up was performed. Morphological characteristics were observed. Immunohistochemistry, Epstein-Barr virus (EBV) in situ hybridization, clonal rearrangement analysis of T-cell receptor (TCR) genes, and targeted next-generation sequencing (NGS) were performed. Results: Among the 42 patients (male/female ratio of 2.8∶1.0), the age range was 32-77 years with a median age of 59.5 (52.0-65.0) years. Grossly, the tumors were presented as ulcerative or exophytic lesions, with a maximum diameter of 2-18 cm. There were 34 cases with a single lesion and 8 cases with more than 1 lesion. The tumor cells in all 42 cases were relatively monotonous in histology and small or medium in size. They had round or oval nuclei, moderately pale or clear cytoplasm, evenly distributed nuclear chromatin, inconspicuous nucleoli, and frequent mitotic figures. In one of the cases, there were moderately large cells, vacuolated nuclei, and clear nucleoli. Lymphoepithelial lesions were observed in 36 (85.7%) of the 42 cases, tumor necrosis in 4 (9.5%) cases, scattered eosinophils and/or plasma cell infiltration in the background in 9 (21.4%) cases, and a "starry sky" phenomenon in 1 (2.4%) case. The tumor cells in all cases exhibited high expression of CD3, CD2, CD7, CD8, CD56, TIA1, Granzyme B, and Perforin, while some also expressed CD4 (5/41, 12.2%), CD5 (3/41, 7.3%), CD20 (4/41, 11.9%), CD79α (2/37, 5.4%), and CD30 (1/34, 2.9%). The Ki-67 proliferation index ranged from 40% to 90%. EBER in situ hybridization tests were negative in all cases. TCR gene clonal rearrangement was detected in 96.4% (27/28) of the tested cases. Targeted NGS revealed commonly mutated genes including SETD2, STAT5B, JAK3, TP53, and CREBBP. The primary treatment was chemotherapy, with 2 cases undergoing autologous hematopoietic stem cell transplantation. Follow-up information was obtained for 29 cases, with a follow-up period of 1-73 months. The mortality was 93.1% (27/29). Conclusions: MEITL is a rare and highly aggressive peripheral T-cell lymphoma. Its clinical manifestations are diverse, and diagnosis primarily relies on a comprehensive assessment of pathological morphology, immunohistochemical profiles, and EBV infection status, supplemented by genetic testing if necessary. At present, there is no effective treatment, and its overall prognosis is poor.