Cutaneous Langerhans Cell Sarcoma: A Case Report.

Background: Langerhans Cells are a subset of antigen-presenting dendritic cells belonging to the histiocytic system and are classified into Langerhans cell histiocytosis and Langerhans cell sarcoma. Histiocyte tumors are among the more uncommon neoplasms affecting lymphoid tissues, probably representing less than 1% of all malignancies involving lymph nodes or soft tissues. Langerhans cell sarcoma can be limited to the skin, or it can spread to other organs. To the best of our knowledge, primary cutaneous Langerhans cell sarcoma without any extracutaneous associations is extremely rare; we describe a young male patient with this rare condition. Materials and Method: After the surgical excision the specimen underwent to Immunohistochemistry staining showing that the tumor cells were diffusely positive for vimentin, S-100, CD68, CD1a, and langerin but negative for melan-A and pan-cytokeratin. The Ki-67 proliferating index was high at approximately 12%. Discussion and Conclusion: Histiocytoses are rare neoplasms with a highly unpredictable clinical course ranging from spontaneous regression to highly aggressive, even fatal, disease. Cutaneous Langerhans cell sarcoma, with its rareness in skin and its poorly differentiated morphologic features, shares a differential diagnosis with other epithelial or mesenchymal skin neoplasms nonetheless the typical immunophenotype features langerin, CD1a, and S-100 are helpful to achieve an accurate diagnosis of these dendritic-cell tumors.