Objective: To investigate the difference between routine hematoxylin-eosin (HE) staining and immunohistochemistry in diagnosing metastatic melanoma in sentinel lymph node (SLN) metastases, and to evaluate the association of SLN tumor burden with the status of non-sentinel lymph nodes (NSLN). Methods: 126 melanoma patients were treated with SLN biopsy and further examined with immunohistochemistry at Fudan University Shanghai Cancer Center between 2010 and 2016, and the status of SLN was respectively estimated by HE stain and immunohistochemistry (S-100 protein, HMB45, Melan A and SOX10). In 39 patients who were treated with complete lymph node dissection, characteristics of SLN tumor burden (maximum diameter of the tumor deposit, tumor penetrative depth and the microanatomic location of the metastasis) and the associations of SLN tumor burden with the involvement of NSLN were all evaluated. Results: Of the total 126 cases, 33 (26.2%) were positive by HE staining and 49 (38.3%) were positive by immunohistochemistry. S-100 protein was positive in 48 out of 49 cases (98.0%). HMB45 was positive in 46 out of 49 cases (93.9%). Melan A was positive in 47 out of 49 cases (96.0%). SOX10 was positive in 8 out of 8 cases. The outcome indicated that the application of immunohistochemistry identified positive SLN missed by HE stain in about 12.1% of cases. Of the 39 patients who were treated with complete lymph node dissection, six showed metastases in NSLN. The frequency of metastases in NSLN was 15.4% (6/39) when SLN was positive. Additionally, the frequency of metastases in NSLN in cases with SLN metastatic deposits ≤2 mm was significantly lower than that in cases with SLN metastatic deposits >2 mm; eight cases with SLN metastatic deposits <0.2 mm had no additional positive NSLN. Conclusions The findings suggest that immunohistochemistry could effectively improve the detection of positive SLN in melanoma. Cases with SLN metastatic deposits ≤2 mm are less likely to have further metastases in NSLN. There is a need for prospective large-population based studies to identify a subgroup of SLN positive patients who can safely be spared complete lymph node dissection.

Objective: To evaluate the sensitivity, specificity and clinical value of anti-BRAF V600E antibody (clone VE1) in detection of the BRAF V600E mutant in formalin-fixed and paraffin-embedded (FFPE) melanoma specimens by immunohistochemical (IHC) methods. Methods: A total of 50 melanoma samples collected between 2008 and 2016 from 40 patients were analyzed for BRAF mutation (exon 15) by DNA sequencing using FFPE. These tissues were immunostained with VE1 antibody, and the results were analyzed and compared with those by DNA sequencing. Results: By DNA sequencing, 36 cases showed BRAF mutation while others were BRAF wild type. Among the 36 cases with BRAF mutation, 32 harbored BRAF V600E, two harbored BRAF V600K, one had BRAF K601E and one had BRAF D594N, respectively. IHC staining showed 30 specimens were VE1 positive, while 19 were negative. The determination of IHC result for one case was obscured by heavy pigments. Of the BRAF-mutated specimens, four specimens with BRAF mutation other than V600E were all negative for VE1. The sensitivity and specificity of the VE1 immunostaining was 96.8% and 100.0% respectively.Concordance of BRAF V600E detection between immunostaining and DNA sequencing was 98.0%(48/49). Conclusions High sensitivity and specificity for VE1 immunostaining in detecting BRAF V600E in melanomas are demonstrated. It is a rapid and cost-effective method for detecting BRAF V600E mutations in melanoma patients. Hence, VE1 immunostaining can be used as an important screening method for BRAF mutation in laboratories.

Objective:To investigate the clinicopathological characteristics of spiradenocarcinoma, cylindrocarcinoma, and spiradenocylindrocarcinoma, and to understand the correlations between their morphological patterns and clinical behaviors.Methods:Seven cases of spiradenocarcinoma, cylindrocarcinoma, and spiradenocylindrocarcinoma diagnosed at Fudan University Shanghai Cancer Center, Shanghai, China from 2015 to 2021 were collected. The clinicopathological characteristics and follow-up data were retrospectively analyzed. Histopathologic evaluation and immunohistochemical studies were carried out.Results:There were four men and three women in the cohort, with ages ranging from 46 to 75 years (mean, 61 years). The tumors were located on the head and neck (four cases), extremities (two cases), and trunk (one case). Histologically, the residuum of a benign neoplasm was present in all cases. One case presented salivary gland-type basal cell adenocarcinoma-like pattern, low-grade (BCAC-LG). Another case showed salivary gland-type basal cell adenocarcinoma-like pattern, high-grade (BCAC-HG). The remaining five cases were invasive adenocarcinoma, not otherwise specified (IAC-NOS). One of IAC-NOS contained a mucinous adenocarcinoma component. Immunohistochemically, BCAC-LG and BCAC-HG predominantly expressed basal cell markers such as p63 and p40, whereas IAC-NOS primarily exhibited positivity for CK7, a glandular epithelial marker. Follow-up was available for six patients, ranging from 1 to 9 years (mean, 4.5 years). Among the four patients of IAC-NOS with follow-up, three showed recurrences, two had regional lymph node metastases, and one died.Conclusions:The malignant components of spiradenocarcinomas, cylindrocarcinomas, and spiradenocylindrocarcinomas in this cohort contain BCAC-LG, BCAC-HG and IAC-NOS. This study also shows the presence of mucinous adenocarcinoma components in IAC-NOS. The tumors with IAC-NOS have a relatively poorer prognosis than those without.