Histopathologic examination of the enucleated subcutaneous nodule revealed a well-encapsulated mass composed of interlacing fascicles of spindle cells. The nodule was composed of multiple lobules that were incompletely separated by dense fibrous collagen bands. In some areas, the fascicles were loosely arranged, mimicking neurofibroma. A fibrous capsule composed of flattened, elongated cells was present around the nodule. The tumor cells were positive for S100 protein and vimentin and negative for α-smooth muscle actin. On immunohistochemical analysis, the cells of the capsule were positive for epithelial membrane antigen.
A Freely Movable Subcutaneous Nodule on the Dorsum of the Hand—Diagnosis. Arch Dermatol. 2004;140(8):1003-1008. doi:10.1001/archderm.140.8.1003-d