[Secondary telangiectatic osteosarcoma of the left femur. A case presentation of an unusual course of disease].

BACKGROUND: This article presents the unusual case of a 73-year-old male patient who was treated with primary interlocking nailing after a pathological femoral fracture. DIAGNOSTICS: Despite comprehensive diagnostics including several biopsies, a tumor could not be detected. In 2008 when progressive cystic femoral destruction leading to loosening of the nail necessitated a partial femoral prosthesis, an osteosarcoma could first be diagnosed in the resected bone. THERAPY: Advanced progression of the tumor required an extended hip exarticulation. During the current restaging of the now 84-year-old patient no tumor could be detected.
CONCLUSION: When a malignancy cannot be excluded even by repeated biopsies of radiologically suspicious structures, an adequate tumor staging followed by close monitoring should be carried out. For a clinically silent, long-term course of cystic destruction of a long bone over several years, an age over 60 years and a lack of distant metastases, an atypical osteosarcoma should be considered in the differential diagnosis.