A 30-year old male with the tumor of the anterior femoral region that previously has arised for several months.  
The tumor was surgically removed.  
Gross examination revealed a multinodular, grayish-white tumor that measured 5.5x4.5 mm. The lesion was ulcarated, poorly circumscribed.  
Microscopically, the tumor was located in both papillary and reticular dermis as well as in subcutis. The lesion was predominantly composed of spindle cells, pleoimorphic, some of them with multinuclear appearance. Some of tumor cells also had a 'dendritic' processes. Tumor cells were located between preserved lymphatic tissue that was composed of primary and secondary lymphatic follicules. Within the germ centers, we noticed the same cells as in the tumor. Both were positive on CD68. The tumor cells were also positive on S100 and Vimentin but was negative on HMB-45, CD1a and CD21.  
What is your diagnosis? Please, give your comments.