GIANT CELL TUMOR OF TENDON SHEATH ORIGIN
This type of tumor is encountered most frequently by the general pathologist as an excised mass. The dermatopathologist will see an occasional case since there may be involvement of the deep dermis, particularly in cases involving the distal aspect of a finger. When encountered in a skin specimen, the tumor is sharply circumscribed and there may be a suggestion of lobulation. The basic cell population is a round or polygonal histiocytic or fibrohistiocytic cell. Giant cells are usually present, but the number is quite  variable from case to case. Ordinary histiocytic giant cells may be seen, and osteoclastic type giant cells may also be present. Foamy histiocytes and hemosiderin laden histiocytes are seen in some cases. Lesions of this type are considered benign, but about 10% recur.
 
Scan power view. The tumor is much more sharply circumscribed than a dermatofibroma. There is a suggestion of lobulation that is created by the presence of fibrous septa that curve within the tumor.
Medium power view. A fibrous septum is seen near the right side of the picture. The basic round or polygonal histiocytes are occasionally found in ribbons within dense fibrous tissue.
High power view of above. A multinucleated histiocyte is in the center of the field.
High power view from another area. There is an osteoclastic type giant cell in the center of the picture.. The cytoplasm is a dark lavender color, and the nuclei are also darkly stained. Note the basic histiocyte or fibrohistiocytic cell component associated with dense fibrous tissue.

Click on your browser's 'Back' button to return to the previous page.