Exposing the Great Imitator: Proposal for a Holistic Diagnosis of Oral Secondary Syphilis in People Living with HIV.

Oral secondary syphilis may mimic various infectious, neoplastic, or immune-mediated processes; hence, its diagnosis may represent a challenge. Early diagnosis of syphilis, a disease that has increased in recent decades, is essential for adequate management, particularly in people living with HIV (PLWH). This study aimed to comprehensively characterize oral secondary syphilis in a group of 47 PLWH. A group of PLWH with oral secondary syphilis attending four HIV-referral centers in Mexico City was included (2004-2021). Clinical and laboratory data were retrieved, and an exhaustive oral examination was performed following the established criteria. Demographic, clinicopathological, immunohistochemical, and serological features of the patients were analyzed. Approximately 11% of PLWH with oral secondary syphilis demonstrated negative Venereal Disease Research Laboratory tests. A noticeable feature was the absence of symptoms in 95.7% of cases, despite the clinically evident appearance of the lesions. In contrast to previous results, 18% of ulcerations were detected to be deep, crateriform, and infiltrative, and 22% of the mucous patches were highly keratotic lesions. Most samples (77.3%) showed superficial lymphoplasmacytic infiltrates in the superficial lamina propria, with perivascular and perineural patterns, and immunohistochemistry was positive in 66.7% of the cases. The "great imitator" appears not only clinically but also histopathologically and immunohistochemically, where features may be comparable with those of chronic inflammatory processes, deep infections, or malignant processes. Although not recommended as a routine assay, IHC could be a critical tool, particularly in PLWH with atypical clinical features or with negative and/or dubious serology.

CD117 immunoexpression in oral and sinonasal mucosal melanoma does not correlate with somatic driver mutations in the MAPK pathway.

BACKGROUND: Mutations on KIT and downstream genes of MAPK pathway that overstimulate cellular proliferation have been associated with primary oral and sinonasal melanomas (POSNM), but there is limited information that allows the use of personalized therapy. Thus, the aim of the present study was to determine a possible association between the C-KIT immunohistochemical expression with the presence of somatic driver mutations in NRAS, BRAF, KIT, MITF and PTEN on POSNM. METHODS: A retrospective study included 62 tumour samples of an oncological reference centre in Mexico City (17-year period). Immunohistochemistry stain of C-KIT was carried out. Genomic DNA was obtained and used to assess hotspot mutations of KIT, NRAS, BRAF, MITF and PTEN through qPCR. Chi-square, Fisher's exact and the Mann-Whitney U tests were applied when necessary. The significance was set at P < 0.05. RESULTS: Sixty-two cases were included, 74% were positive for C-KIT immunoexpression, all exhibited moderate/strong intensity. Ten (16.1%) samples harboured at least one mutation, 6.4% and 6.6% for NRASQ 61R and BRAFV 600E , respectively, followed by KITK624E (3.2%). No KITL 576P , MITF or PTEN mutations were identified. No significant correlation was observed between mutations and immunostaining (rs = -0.057, P = 0.765). CONCLUSIONS: Regardless of the high immunoexpression of C-KIT, there was no association with the MAPK mutations among POSNM samples. Thus, C-KIT immunohistochemistry is not a reliable tool to detect POSNM candidates for biological therapy.

Frequency of BRAF V600E Mutation in the Mexican Population of Patients With Metastatic Melanoma.

PURPOSE: The BRAF V600E mutation has been described in melanomas occurring in the Caucasian, European, and Asian populations. However, in the Mexican population, the status and clinical significance of BRAF mutation has not been researched on a large scale. METHODS: Consecutive BRAF-tested Mexican patients with metastatic melanoma (n = 127) were analyzed for mutations in exon 15 of the BRAF gene in genomic DNA by real-time polymerase chain reaction technology for amplification and detection. The results were correlated with the clinical-pathologic features and the prognosis of the patients. RESULTS: The frequency of somatic mutation V600E within the BRAF gene was 54.6% (43 of 127 patients). Nodular melanoma was the most prevalent subtype in our population, with BRAF mutations in 37.2% (16 of 55 patients). In contrast, superficial spread had a frequency of 18.6% BRAF mutation (eight of 24). Other clinicopathologic features were assessed to correlate with the mutation status. CONCLUSION: This study searched for the most prevalent BRAF V600E mutation type in melanoma in a heterogeneous population from Mexico. Nodular melanoma was found to be the most prevalent in metastatic presentation and the presence of BRAF V600E mutation, perhaps related to the mixed ancestry; in the north, ancestry is predominantly European and in the south, it is predominantly Asian. The outcomes of the mutation correlations were similar to those found in other populations.