An 85-year-old white man with a history of nonmelanoma skin cancer including basal cell carcinomas (BCCs) and a remote history of smoking 50 years ago presented with a 1.4-cm nodule of the right neck and an incisional biopsy was performed (Figure 1). The biopsy specimen showed nodular BCC with a dense infiltrate of histiocytic cells that tested positive with S-100 and CD1a immunostains, consistent with Langerhans cell histiocytosis (LCH) (Figure 2A-C). However, the cells tested negative with a langerin immunostain (Figure 2D) and positive with CD68. Electron microscopy (EM) was not performed. The collision tumor was completely excised.
Strahan JE, Chorny JA, Cohen JL, Fujita M. Combined Multifocal Indeterminate Cell Histiocytosis and Basal Cell Carcinoma. Arch Dermatol. 2010;146(3):346-347. doi:10.1001/archdermatol.2010.13