Multifocal BRAF(V600E)-Mutated Melanoma in situ on the Foot.

Melanoma is an aggressive skin cancer that originates from melanocytes, and about one half of melanoma cases possess a BRAF mutation. Together with PD-L1 expression, the BRAF(V600E) mutation is one of the optimal therapeutic targets for the treatment of melanoma. In this report, we describe a case of multifocal melanoma in situ on the foot, which carried the p.V600E mutation in the BRAF gene. Interestingly, the spotted melanoma lesion is demarcated by normal skin, and in all spotted pigmented lesions, there were no signs of dermal invasion of melanoma cells or spontaneous regression. Our case presented atypical clinical features, which might correlate with the local mutations of BRAF gene and the immunological expression of PD-L1.

Merkel Cell Carcinoma Concomitant with Invasive Bowen's Disease: Immunohistochemical Investigation of Tumor-Infiltrating Leukocytes.

Merkel cell carcinoma (MCC) is an aggressive, cutaneous, neuroendocrine carcinoma and, in rare cases, occurs with Bowen's disease (BD). In this report, we describe a case of MCC concurrent with invasive BD and compare the profiles of tumor-infiltrating leukocytes in the lesional skin of MCC and invasive BD. Interestingly, immunohistochemical study revealed significant numbers of CD8+ cells and caspase 3-expressing cells in the same areas of invasive BD and MCC. Our present case suggests that MCC concurrent with invasive BD might have a good prognosis because of the substantial number of CD8+ cells in the tumor.