Desmoplastic fibroma of bone is a rare benign tumor consisting of thin,
wavy fibroblasts set in an abundant matrix of collagen fibers. At times it
is difficult to distinguish desmoplastic fibroma from other fibrous
lesions, especially low-grade fibrosarcomas. Fewer than eight cases have
been previously reported. We have reviewed the diagnostic and therapeutic
findings of eighty additional cases. Six patients had the lesions located
in an extremity and two had an axial lesion. The average age of the
patients was twenty-five years (range, twelve to fifty-six years) and all
of the patients had more than two years of follow-up (range, two to
seventeen years). The radiographic findings in all but one patient were of
a purely lytic, honeycombed lesion that often widened the bone, and was
metaphyseal in long bones. The tumor replaced the medullary cavity with a
grayish-white, rubbery to firm tissue that was often, but not always,
contained by a rim of periosteal reactive bone. Histologically, the
features were: (1) prominent loose bundles of fibrous tissue composed of
slim, spindle-shaped fibroblasts with wavy, elongated nuclei; (2) variable
amounts of bands of collagen fibers; and (3) absence of mitoses or atypical
cells. Areas of metaplastic bone were found only around sites, of
pathological fractures. The biology of desmoplastic fibroma is different
from that of other benign fibrous lesions in that the lesion is very
destructive locally and often recurs after incomplete excision. It is also
distinguished from low-grade malignant lesions (for example, fibrosarcoma)
in that metastases have never been reported. In our series an intralesional
excision was initially performed in six of the eight patients and a
marginal resection, in two. There were four recurrences, treated by a
marginal resection in two patients and repeat curettage in one. The
recurrence in the fourth patient required an amputation above the knee
after two additional intralesional procedures had been unsuccessful. Wide
or marginal resection appears to be the treatment of choice when the lesion
is located in a site that can be resected without significant loss of
function. In other areas, an attempt at curettage, instillation of phenol,
and bone-grafting seems to be warranted, resorting to more radical
procedures only if this fails to control local disease.