Desmoplastic fibroma of bone is a very rare primary bone
tumor morphologically resembling
desmoid-type
fibromatosis, its much more common counterpart of soft tissue. The aim of this study is to investigate the immunohistochemical profile and the involvement of the
beta-catenin pathway in
desmoplastic fibroma as it is known in
desmoid-type
fibromatosis. Immunohistochemistry was performed on 13 cases of
desmoplastic fibroma for muscle-specific markers,
estrogen and
progesterone receptors, CD117,
beta-catenin, and the potential downstream target of
beta-catenin, namely,
cyclin D1. In all 13 cases,
DNA sequencing was performed for the detection of activating
beta-catenin gene mutations. There was no immunoreactivity of CD117,
estrogen, and
progesterone receptors. Seven cases were immunoreactive for one or more muscle-specific markers. In 6 cases, there was overexpression of
beta-catenin in the cytoplasm; in one of these cases, there was also accumulation of
beta-catenin in the nucleus. In 6 cases in which
DNA sequencing was successful, no
beta-catenin mutations were detected. Search in a national database showed that not a single case over a frame of 23 years was associated with occurrence of
colon cancer in the same patient. The epidemiological, histological, and immunohistochemical findings in
desmoplastic fibroma are suggestive of
desmoplastic fibroma being the bony counterpart of the more common
desmoid-type
fibromatosis of soft tissue. However, the
beta-catenin pathway does not seem to have the same essential role in the
tumorigenesis of
desmoplastic fibroma, as it has in
desmoid-type
fibromatosis.