Recurrent benign fibrous histiocytoma of the bone benefits from denosumab followed by malignant transformation: a case report.

Benign fibrous histiocytoma of the bone (BFHB) is a rare mesenchymal tumor, representing less than 1% of all benign bone tumors. This controversial entity is characterized by a mixture of fibroblasts arranged in a storiform pattern, varying amounts of osteoclast-type giant cells and foamy macrophages. Curettage or simple resection is usually curative. However, it was reported that up to 11% of the patients suffer from relapse. Here, we report a case of malignant transformation of BFHB after long-lasting disease stabilization under denosumab therapy.

The Unresolved Case of Sacral Chordoma: From Misdiagnosis to Challenging Surgery and Medical Therapy Resistance

PURPOSE: A sacral chordoma is a rare, slow-growing, primary bone tumor, arising from embryonic notochordal remnants. Radical surgery is the only hope for cure. The aim of our present study is to analyse our experience with the challenging treatment of this rare tumor, to review current treatment modalities and to assess the outcome based on R status. METHODS: Eight patients were treated in our institution between 2001 and 2011. All patients were discussed by a multidisciplinary tumor board, and an en bloc surgical resection by posterior perineal access only or by combined anterior/posterior accesses was planned based on tumor extension. RESULTS: Seven patients underwent radical surgery, and one was treated by using local cryotherapy alone due to low performance status. Three misdiagnosed patients had primary surgery at another hospital with R1 margins. Reresection margins in our institution were R1 in two and R0 in one, and all three recurred. Four patients were primarily operated on at our institution and had en bloc surgery with R0 resection margins. One had local recurrence after 18 months. The overall morbidity rate was 86% (6/7 patients) and was mostly related to the perineal wound. Overall, 3 out of 7 resected patients were disease-free at a median follow-up of 2.9 years (range, 1.6-8.0 years). CONCLUSION: Our experience confirms the importance of early correct diagnosis and of an R0 resection for a sacral chordoma invading pelvic structures. It is a rare disease that requires a challenging multidisciplinary treatment, which should ideally be performed in a tertiary referral center.