Spatially and cell-type resolved quantitative proteomic atlas of healthy human skin.

Human skin provides both physical integrity and immunological protection from the external environment using functionally distinct layers, cell types and extracellular matrix. Despite its central role in human health and disease, the constituent proteins of skin have not been systematically characterized. Here, we combine advanced tissue dissection methods, flow cytometry and state-of-the-art proteomics to describe a spatially-resolved quantitative proteomic atlas of human skin. We quantify 10,701 proteins as a function of their spatial location and cellular origin. The resulting protein atlas and our initial data analyses demonstrate the value of proteomics for understanding cell-type diversity within the skin. We describe the quantitative distribution of structural proteins, known and previously undescribed proteins specific to cellular subsets and those with specialized immunological functions such as cytokines and chemokines. We anticipate that this proteomic atlas of human skin will become an essential community resource for basic and translational research ( https://skin.science/ ).

Cutaneous Metastases from Salivary Duct Carcinoma of the Submandibular Gland.

Salivary duct carcinoma is a rare and highly aggressive malignant neoplasm that frequently metastasises to other organs, but cutaneous metastasis is uncommon. There are only 6 cases reported in the literature with metastases to the skin and in all cases the tumour originates from the parotid gland. We present a case of skin metastases from the submandibular gland that was mistaken for basal cell carcinoma. To the best of our knowledge, this is the first reported case of salivary duct carcinoma arising from the submandibular gland with cutaneous metastases.