Abstract
Langerhans Cell Sarcoma (LCS) is a rare high-grade neoplasm of antigen presenting dendritic cells which portends high morbidity and mortality. LCS is characterized by cytological atypia, frequent mitoses and aggressive clinical behavior.1 It can present with extensive systemic involvement or as a primary cutaneous lesion. Primary cutaneous LCS (PCLCS) is exceptionally rare with only 12 cases reported in the literature. We present a case of PCLCS occurring in a middle-aged female with a bleeding scalp lesion of one month duration. Histology was significant for diffuse proliferation of large and atypical histiocytoid cells with enlarged, focally reniform nuclei, conspicuous nucleoli, and numerous atypical mitoses. By immunohistochemistry, the cells were positive for S100, CD163, CD45, and CD4, and showed patchy positivity for CD68 and Langerin, and focal positivity for CD1a. The tumor cells were negative for AE1/AE3, CD3, CD20, CD21, CD23, CD30, HMB45, SOX10, Melan-A, desmin, and BRAFV600E. The Ki67 index was approximately 30%. PET scan showed no signs of metastatic disease. She underwent wide local excision with 1 cm margins without adjuvant therapy. The patient remained clinically free of disease one year after initial diagnosis. Considering the rare nature of PCLCS, this case provides further examples of pathologic findings and immunophenotyping, which are essential to the accurate diagnosis of this high-grade neoplasm, and provides follow up data after conservative management. Additionally, we provide a concise summary of the known PCLCS cases to date.
1. Howard JE, Dwivedi RC, Masterson L, Jani P. Langerhans cell sarcoma: a systematic review. Cancer Treat Rev. 2015 Apr;41(4):320-31. doi: 10.1016/j.ctrv.2015.02.011. Epub 2015. PMID:25805533