Fig. 2

Pathological findings. a Macroscopic findings. The excised section of the tumor shows only a solid component, without a cystic component or apparent capsule. b Microscopic findings. A tumor without fibrous capsule with interlacing bands of uniform spindle cells, of which elongated nuclei are arranged in a palisading pattern. c, d Immunohistochemical findings The epithelioid spindle cells are strongly positively stained for (c) human melanoma black 45 and (d) desmin. e CD34 underlined the rich demonstrate abundant mature vascular structures. f The tumor cells are focally positive for S100