Background: Desmoplastic fibroblastoma (collagenous fibroma) is an uncommon benign soft-tissue tumor, rarely involving bone.
Desmoplastic fibroblastoma is an uncommon benign soft-tissue tumor, which was first described by Evans in 1995.
Of the 16 cases of soft-tissue desmoplastic fibroblastoma, 15 were obtained from surgical procedures in the Department of Hand Surgery and one case of bone was derived from a surgical procedure in the Department of Orthopedic Oncology.
Formalin-fixed, paraffin-embedded specimens of 16 cases of desmoplastic fibroblastoma were available for immunohistochemical analysis.
In the one case of desmoplastic fibroblastoma of bone, the X-ray of the right proximal femur showed an osteolytic lesion with a well-defined sclerotic rim, but lack of matrix calcification [Figure 1]b.
The sample of bone desmoplastic fibroblastoma obtained from the curettage surgery showed a gray fragmented tissue, in which some cystic areas existed.
The histological features of desmoplastic fibroblastoma of bone were similar to those of soft tissue, except cystic degeneration.
However, the immunostaining signal of other markers was absent in the section of all tissues, which confirmed the diagnosis of desmoplastic fibroblastoma.
In our desmoplastic fibroblastoma cases, except for the one case involving the long bone, others were located in the soft tissue of shoulder, feet, hands, or arms.
Occasionally, invasion of desmoplastic fibroblastoma into the bone tissue was reported;, but primary tumor that arose in the bone was not found previously.