Objective:To investigate the clinicopathological features of Erdheim-Chester disease (ECD) initially diagnosed at extraskeletal locations.Methods:Clinical and pathological data of four cases of ECD diagnosed initially in extraskeletal locations were collected at Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, from January 2013 to June 2023. BRAF V600E gene was detected by reverse transcription polymerase chain reaction (RT-PCR). Pertinent literatures were reviewed.Results:Four ECD patients included two males and two females ranging in ages from 2 years 11 months to 69 years. The lesions located in the lung (two cases), central nervous system (one case), and the testicle (one case) were collected in the study. One patient had occasional fever at night, one had nausea and vomiting, and two were asymptomatic. Radiologically, the two pulmonary ECD showed diffuse ground-glass nodules in both lungs, and the lesions in central nervous system and testicle both showed solid masses. Microscopically, there were infiltration of foamy histiocyte-like cells and multinucleated giant cells in a fibrotic background, accompanied by varying amounts of lymphocytes and plasma cells. The infiltration of tumor cells in pulmonary ECD was mainly seen in the subpleural area, interlobular septa, and perivascular and peribronchiolar areas. The fibrosis was more pronounced in the pleura and interlobular septa, and less pronounced in the alveolar septa. Immunohistochemical staining showed that all tumor cells expressed CD68, CD163 and F a; one case showed S-100 expression; three cases were positive for BRAF V600E; all were negative for CD1α and Langerin. RT-PCR in all four cases showed BRAF V600E gene mutation. Conclusions:Extraskeletal ECD is often rare and occult, and could be easily misdiagnosed, requiring biopsy confirmation. The radiologic findings of pulmonary ECD is significantly different from other types of ECD, and the histopathological features of pronounced infiltration in the subpleura area, interlobular septa, perivascular and peribronchiolar areas can be helpful in the differential diagnosis from other pulmonary diseases. Detection of BRAF V600E gene mutation by RT-PCR and its expression by immunohistochemical staining are also helpful in the diagnosis.

Objective:To study the pathological changes of the spleen in patients with COVID-19 and to analyze the relationship between the weakened immune system and splenic lesions.Methods:Postmortem needle autopsies from the spleen were carried out on 10 patients who died from COVID-19 in Wuhan. Routine hematoxylin and eosin (HE) staining was used to observe the pathological changes. The changes of lymphocytes were studied further with immunohistochemistry.RT-PCR was used to detect 2019-nCoV RNA in the spleen. In addition,the Epstein-Barr virus (EBV) was detected by in situ hybridization, and coronavirus particles were detected by transmission electron microscopy in 2 cases.Results:There were 7 males and 3 females, with an average age of 68.3 years.Of the 10 cases, 4 had cancer history and another 4 had other underlying diseases respectively.Cough, fever, malaise and dyspnea were the main clinical symptoms.The time from onset to death was 15-45 days.Ten cases patients had normal or slight increase in peripheral blood leukocyte count in the early stage of the disease, 6 cases had significant increase before death. Five patients′ peripheral blood lymphocyte count decreased in the early stage of the disease, and 10 patients′ peripheral blood lymphocyte count decreased significantly before the disease progressed or died. Seven cases were treated with corticosteroid (methylprednisolone ≤40?mg/d, not more than 5 days). Histopathological examination showed that the cell composition of the spleen decreased, white pulp atrophied at different levels, meanwhile lymphoid follicles decreased or absent;in addition, the ratio of red pulp to white pulp increased with varying degrees. In 7 cases, more neutrophil infiltration was found, and in 5 cases, scattered plasma cell infiltration was found. Macrophage proliferation and hemophagocytic phenomena in a few cells were found in a case. Meanwhile, necrosis and lymphocyte apoptosis were detected in 2 cases, small artery thrombosis and spleen infarction in 1 case, and fungal infection in 1 case. The results of immunohistochemistry showed that the T and B lymphocyte components of the spleen in all cases decreased in varying degrees. CD20 + B cells were found to accumulate in the lymphoid sheath around the splenic artery in 8 cases. However, CD20 and CD21 immunostaining in 2 cases showed that the number of white pulp was almost normal, and splenic nodules were atrophic. CD3 +, CD4 + and CD8 +T cells were decreased. In 9 cases,CD68 + macrophages were no significant changes in the distribution and quantity. While more CD68 + cells were found in the medullary sinuses of 1 case (related to fungal infection). Few CD56 + cells were found. EBV was negative by in situ hybridization. RT-PCR was used to detect the nucleic acid of 2019-nCoV. One of 10 cases was positive, 39 years old,who was the youngest patient in this group, and the other 9 cases were negative. Coronavirus particles were found in the cytoplasm of macrophage under electron microscope in 2 cases. Conclusions:The death of COVID-19 occurs mainly in the elderly, and some cases have no underlying diseases. Spleen may be one of the organs directly attacked by the virus in some patients who died from COVID-19. T and B lymphocyte in the spleen decrease in varying degrees, lymphoid follicles are atrophied, decreased or absent, and the number of NK cells do not change significantly. And the pathological changes of the spleen are not related to the use of low dose corticosteroid, which may be related to the direct attack of virus and the attack of immune system on its own tissues.

Objectives:To observe the pulmonary changes with coronavirus disease 2019 (COVID-19) in postmortem needle specimens, to detect the presence of 2019 novel coronavirus(2019-nCoV) in the lung tissues, and to analyze the clinicopathological characteristics.Methods:For 10 decedents with 2019-nCoV infection in Wuhan, bilateral lungs underwent ultrasound-guided percutaneous multi-point puncture autopsy, and pulmonary pathological changes were described in routine hematoxylin-eosin staining (HE) slides. Electron microscopy was also performed. The reverse transcription polymerase chain reaction (RT-PCR) was employed to detect 2019-nCoV nucleic acid in lung tissue, and the pathological characteristics were demonstrated in combination with clinical data analysis.Results:Of the 10 deaths associated with COVID-19, 7 were male and 3 were female. The average age was 70 (39-87) years. Medical record showed that 7 patients had underlying diseases. The average course of disease was 30 (16-36) days. Nine cases showed fibrinous and suppurative exudation in the alveolar cavity accompanied by the formation of hyaline membrane, and fibroblastic proliferation of alveolar septum. Type Ⅱ alveolar epithelial cells showed reactive hyperplasia and desquamation. Many macrophages accumulated in the alveolar cavity. Capillary hyaline thrombus and intravascular mixed thrombus were noted. In some cases, acute bronchiolitis with mucous membrane exfoliation, accumulation of bronchiolar secretions, and bronchiolar epithelial metaplasia occurred. In the cohort, a large number of bacteria (cocci) were detected in 1 case and a large number of fungi (yeast type) were detected in 1 case. Nine cases were positive for the nucleic acids of 2019-nCoV while one case remained negative by RT-PCR. Coronavirus particles were detected in the cytoplasm of type Ⅱ alveolar epithelium.Conclusions:The pulmonary pathological changes of fatal COVID-19 are diffuse alveolar damage (DAD), mainly in the acute exudative stage and the organic proliferative stage. There are fibrinous exudate aggregation in alveolar cavity with hyaline membrane formation, fibroblastic proliferation in alveolar septum, and alveolar epithelial cell injuries with reactive hyperplasia and desquamation of type Ⅱ alveolar epithelial cells. A large amount of neutrophils and monocytes infiltration is present in most cases and bacteria and fungi are detected in some cases, suggesting a serious bacterial or fungal infection secondary to the DAD.

Purpose To investigate the clinicopathologic,immunophenotypic features,genetic alterations and prognosis of melanotic Xp11 neoplasms/melanotic TFE3-rearrangement neo-plasms.Methods Five cases were selected from the Depart-ment of Pathology,Union Hospital,Huazhong University of Sci-ence and Technology from November 2018 to July 2023.The clinicopathologic,immunohistochemical,FISH assays,next-generation sequencing(NGS)and follow-up details were collect-ed.Results There were 1 male and 4 females,with their ages ranging from 16 to 59 years(mean 28.2 years).The maximum diameters of the masses were 3-6 cm(average 4.7 cm).The tumors located in right kidneys(3 cases),tubal interstitium(1 case)and pelvis(1 case).Microscopically,most tumors shared similar morphology such as nested,acinar structures sep-arated by a delicate vascular network.Epithelioid tumor cells presented with clear to granular eosinophilic cytoplasm.Lym-phocytic infiltration was seen in the background;melanin depo-sition was noted in the cases;neoplastic necrosis was detected in 4 cases.Mitotic activity was low with 5 cases showing＜3/10 HPF.Intravascular tumor thrombus was detected in 2 cases,no lymphovascular and nerve invasions were detected in other 3 ca-ses.Immunohistochemically,all 5 cases expressed TFE3 dif-fusely,and expressed HMB45,Melan A to varying degrees,CK(AE1/AE3),CK7,EMA,PAX8,TFEB,S-100,SOX10,SMA,desmin were all non-reactive in the 5 cases.The Ki67-la-beling index was＜20％.TFE3 separation signal in 4 cases were detected by FISH,1 case was interpreted as negative due to atypical signal which was confirmed by next-generation se-quencing(NGS)assay as RBM10-TFE3.Clinical follow-up was available for five patients for 2-60 months,in which four pa-tients were alive with no evidence of disease after initial resec-tion,and one patient with thoracic spine metastasis was currently in stable condition.Conclusion Melanotic Xp1 1 neoplasms/melanotic TFE3-rearrangement neoplasms has unique morpholog-ic,immunophenotypic and genetic characteristics.It might be reclassified into a distinctive malignant mesenchymal tumor enti-ty.

Objective:To investigate the clinical, cytomorphology, immunocytochemical and molecular features of metastatic melanoma in serosal cavity effusion.Methods:Cytological specimens of 14 patients with melanoma in the chest and abdomen were collected from 2017 to 2023, at the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. SOX10, S-100 protein, PRAME, BRAF V600E, HMB45, and Melan A were detected by immunocytochemical methods. Fourteen cases were tested for routine antibody combinations, including Claudin4, HEG1, Calretinin, CD68, etc. Four of the patients had biopsy or surgical samples of metastatic solid lesions of primary sites, and further next-generation sequencing (NGS) or amplification refractory mutation system (ARMS)-PCR molecular test was performed. In addition, 30 cases of serosal effusion samples were collected as control groups (10 cases of benign mesothelial cell reactive hyperplasia, 10 cases of mesothelioma, and 10 cases of metastatic lung adenocarcinoma).Results:Among the 14 cases of melanoma, there were 7 males and 7 females, with ages ranging from 35 to 86 years, and an average age of 57 years, there 10 cases aged ≥50 years. The tumor cells in the serosal effusion varied in morphology and degree of atypia. SOX10 was positive in all 14 cases (14/14), S-100 protein was positive in 10 cases (10/14), PRAME was positive in 12 cases (12/14), BRAF V600E was positive in 10 cases (10/14), HMB45 was positive in 12 cases (12/14), and Melan A was positive in 13 cases (13/14). In 4 patients with histological correlation, the cytological and histological expression of SOX10, BRAF V600E, and PRAME was positive in all 4 cases (4/4); S-100 protein was positive in 2 cases (2/4); and HMB45 and Melan A were positive in 3 cases (3/4). Using NGS or ARMS-PCR, missense mutations of BRAF V600E were detected in all 4 patients; TERT promoter mutations was detected in 1 case; and CDKN2A terminating mutations and MSI1 deletion mutations were detected in the other case. SOX10, S-100, HMB45, Melan A, PRAME and BRAF V600E were all negative in 30 control samples of serosal cavity effusion.Conclusion:By observing the morphology of tumor cells, immunocytochemical test of several combination markers, especially the expression of SOX10, BRAF V600E and PRAME, can help to improve the positive diagnosis rate of melanoma in serous cavity effusion.

Objective: To investigate the clinical characteristics and placental pathology of 2019-nCoV infection in pregnancy, and to evaluate intrauterine vertical transmission potential of 2019-nCoV infection. Methods: The placentas delivered from pregnant women with confirmed 2019-nCoV infection which were received in the Department of Pathology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology collected by February 4th, 2020 and retrospectively studied. Their clinical material including placental tissue and lung CT, and laboratory results were collected, meanwhile, nucleic acid detection of 2019-nCoV of the placentas were performed by RT-PCR. Results: Three placentas delivered from pregnant women with confirmed 2019-nCoV infection, who were all in their third trimester with emergency caesarean section. All of the three patients presented with fever (one before caesarean and two in postpartum), and had no significant leukopenia and lymphopenia. Neonatal throat swabs from three newborns were tested for 2019-nCoV, and all samples were negative for the nucleic acid of 2019-nCoV. One premature infant was transferred to Department of Neonatology due to low birth weight. By the end of February 25, 2020, none of the three patients developed severe 2019-nCoV pneumonia or died(two patients had been cured and discharged, while another one had been transferred to a square cabin hospital for isolation treatment). There were various degrees of fibrin deposition inside and around the villi with local syncytial nodule increases in all three placentas. One case of placenta showed the concomitant morphology of chorionic hemangioma and another one with massive placental infarction. No pathological change of villitis and chorioamnionitis was observed in our observation of three cases. All samples from three placentas were negative for the nucleic acid of 2019-nCoV. Conclusions The clinical characteristics of pregnant women with 2019-nCoV infection in late pregnancy are similar to those of non-pregnant patients, and no severe adverse pregnancy outcome is found in the 3 cases of our observation. Pathological study suggests that there are no morphological changes related to infection in the three placentas. Currently no evidence for intrauterine vertical transmission of 2019-nCoV is found in the three women infected by 2019-nCoV in their late pregnancy.