Objective To evaluate the application value of confocal laser scanning microscopy(CLSM)in the differentiation between seborrheic keratosis and Bowen′s disease. Methods CLSM was used to observe typical skin lesions in 88 patients clinically diagnosed with seborrheic keratosis and 18 patients clinically diagnosed with Bowen′s disease. Then, tissue specimens were resected from these lesions and subjected to histopathological examination. Results CLSM imaging of seborrheic keratosis lesions showed gyrus?like structures and keratin?filled inclusion cysts in the epidermis with trabecula?like extension of rete ridges in all the 88 cases, basal cells arranged in a cordike or radial pattern in 9 cases, and bright reflective structures in the basal layer and dermis in 6 cases. CLSM imaging of Bowen′s disease lesions revealed disorderly arrangement of large, irregularly shaped atypical cells in some areas in the middle and lower epidermis, and infiltration of scattered mononuclear cells in the superficial dermis. Conclusion CLSM images of seborrheic keratosis are different from those of Bowen′s disease, and CLSM may be helpful for their differential diagnosis.

Objective To investigate the relationship between SFRP1 gene and clinicopathologic features of cutaneous squamous cell carcinoma (CSCC), and to explore the possible mechanism of action of SFRP1 in the occurrence and development of CSCC.Methods CSCC and paracarcinomatous tissue specimens were obtained from 40 patients with CSCC, and normal skin tissue specimens from 40 healthy human controls.The EpiTYPER assay was conducted to evaluate the methylation status of SFRP1 gene promoter in all the specimens with a MassARRAY mass spectrometer.Results Totally, the methylation status of 1951 (86.52％, 1951/2255) CpG motifs were evaluated in 17 CpG loci in 2 fragments of the SFRP1 gene promoter.The methylation rate significantly differed in 10 (10/17, 58.82％) CpG loci between the CSCC and paracarcinomatous tissue specimens, and in 5 (5/17, 29.41％) CpG loci between the paracarcinomatous and normal tissue specimens (all P ＜ 0.05).Furthermore, significant differences were observed in the methylation rates of three CpG loci (CpG 1_5, CpG 1_7, CpG 2_8) in the SFRP1 gene promoter between tissue specimens from different pathological grades of CSCC (P ＜ 0.05), and their methylation rates sequentially decreased from grade Ⅲ to grade Ⅱ and Ⅰ.Conclusion The frequency of methylation is high in the SFRP1 gene promoter in patients with CSCC, and the SFRP1 gene may participate in the occurrence and development of CSCC.

Objective To analyze the clonality in Kaposi's sarcoma (KS) lesions by evaluating Xchromosome inactivation pattern in the human androgen receptor (HUMARA) gene.Methods Twenty-five paraffinembedded tissue specimens were collected from female patients with KS (n =15) or cutaneous hemangioma (n =10).DNA was extracted from these specimens,and digested with the methylation-sensitive restriction endonuclease Hpa Ⅱ.PCR was performed to amplify the HUMARA gene,and the amplicons were separated on a 10％ denaturing polyacrylamied gel and stained with ethidium bromide (EB).The loss of heterozygosity of the HUMARA gene was defined as the presence of two DNA fragments before and one fragment after the endonuclease digestion.The clonality in KS lesions was assessed based on the above results.Results Among the 15 patients with KS,13 (86.7％) were heterozygous for the HUMARA gene,of which,92.31％ (12/13) showed loss of heterozygosity of the HUMARA gene on X-chromosome,suggesting a monoclonal origin.Of the 10 patients with hemangioma,9 were heterozygous for the HUMARA gene,and only one lost heterozygosity of the HUMARA gene.The heterozygosity rate for HUMARA gene was significantly different between the patients with KS and hemangioma (P ＜ 0.01).No statistical difference was observed in the clonality status of KS between patients of different nationality,at different stages,or between patients with and without complicated human immunodeficiency virus (HIV) infection (all P ＞ 0.05).Conclusion KS is monoclonal in origin.

Objective:To investigate clinical and histopathological features and differential diagnostic considerations of mucoepidermoid carcinoma (MEC) .Methods:A retrospective study was carried out on clinical manifestations, histopathological and immunohistochemical features, treatment and prognosis of 8 patients with MEC, who were collected from Department of Pathology, Hospital of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College during 2018 - 2021.Results:Among the 8 patients, 5 were males and 3 were females, and their age at onset ranged from 19 to 67 years. Skin lesions were located on the lip mucosa in 5 cases, on the cheek in 2 cases, and on the nose in 1 case. Tumors were all located in the dermis and subcutaneous tissue, parts of which were connected to the epidermis; different proportions of mucous cells, epidermoid cells and intermediate cells were arranged in nests or clumps, and formed solid or cystic structures accompanied by varying degrees of formation of ducts and mucus lakes; all epidermoid cells and intermediate cells expressed cytokeratins AE1/AE3, CK5/6, P63, carcinoembryonic antigen and epithelial membrane antigen. According to the current Chinese grading system, 1 of the 8 patients was diagnosed with intermediate-grade MEC, and others were diagnosed with low-grade MEC. No abnormalities were found by systemic examination. All patients received surgical resections. After the follow-up of 12 - 36 months, no recurrence or distant metastasis was observed.Conclusion:MEC presents no characteristic clinical manifestations, its diagnosis mainly depends on histopathological features, and mucus in the cytoplasm of mucous cells as shown by alcian blue staining is specific for MEC.