Desmoplastic Fibroma: A Case Report with Three Years of Clinical and Radiographic Observation and Review of the Literature
A 27-year old man presented to our outpatient department with increasing pain in the region of the right sacroiliac joint. The pain started three years earlier, at which point the patient sought help from a local orthopaedic surgeon. At this initial presentation it was thought that his pain was attributable to his physically demanding job. A CT-scan and MRI-scan were performed and revealed a bone cyst with sclerotic borders without destruction of the cortical bone (Figs. , ). Signs of malignancy were not present. Accordingly, the patient was treated with physical therapy, chiropractic treatment, and pain control.\nOver time his pain increased to the point of requiring opioids for pain control and presenting to our hospital. In the interim, he changed his job and decreased his physical activity, neither of which alleviated his pain.\nOn physical examination the patient had tenderness to palpation and vibration over his right sacroiliac joint. Peripheral motor and sensory functions were intact, no pathologic reflexes were present. The patient was in a good general state of health. A CT-scan was repeated and showed a slightly enlarged bone cyst compared to the previous CT-scan three years ago. However, no cortical breakthrough was present (Fig. ).\nFor further diagnostic workup an open biopsy of the lesion was performed one week later. The histological examination of the tissue demonstrated the formation of abundant collagen fibers and spindle shaped cells with medium to low cell density. The nuclei were without pleomorphism and mitotic activity. In immuno-staining the nuclei of the tumor cells were positively labeled for the adhesion protein β-catenin. In addition there was a partially positive staining recognized for S-100. Morphology and immunophenotype were consistent with either aggressive fibromatosis or desmoplastic fibroma, both of which express β-catenin (Fig. ). Because of its intraosseus location the working diagnosis of desmoplastic fibroma was made. Accordingly the indication for operative excision via curettage and grafting was established.\nThe operation was performed with the patient under general anaesthesia. The tumor was removed in several parts. The tissue was beige in color with hard and soft areas of consistency (Fig. ). The removed tumor was sent for further histological examination to the department of pathology.\nThe lesion was filled with autologous bone graft from the iliac crest that was mixed with Cerasorb® (Curasan, Kleinostheim, Germany) and blood from the patient. Operating time was 105 minutes. After surgery the patient was restricted to no weight bearing on the operated side until complete wound healing. Compared to a more invasive treatment option, this therapeutic approach has the advantage of reduced operating time and earlier recovery.\nNo postoperative radiation of the lesion was performed to enable adequate integration of the bone graft.\nHistological workup of the removed tissue demonstrated the identical picture as the biopsy and accordingly no signs of malignancy.\nPostoperative follow-up examinations as well as CT-scans 6 and 18 months after surgery showed good integration of the graft (Figs. , ). There were no signs of recurrence.