Abstract: 【Abstract】 A 44-year-old male patient presented with a subcutaneous nodule in the left little finger for 3 years. Skin examination showed a subcutaneous nodule with rubber-like hardness but no tenderness on palpation, measuring 0.4 cm × 0.4 cm in size at the dorsal distal aspect of the left little finger, and the movement of the distal interphalangeal joint was unrestricted. Postoperative histopathological examination revealed that the tumor contained abundant stroma consisting of variable fiberous, chondroid and myxoid materials; tumor cells were oval to short spindle-shaped with inconspicuous nucleoli but no mitosis; cells were arranged haphazardly or in small clusters. Immunohistochemical study showed positive staining for vimentin, CD34 and transcription factors ERG and SOX9, but negative staining for S100, P63, broad-spectrum cytokeratin AE1/AE3, epithelial membrane antigen, smooth muscle actin and desmin in tumor cells, and the Ki67 labeling index was below 1%. Finally, the patient was diagnosed with acral fibrochondromyxoid tumor.

Key words: Myxoid tumor, Fibrocartilage, Acral fibrochondromyxoid tumor, THBS1ADGFR5