From aneurysmal bone cyst to telangiectatic osteosarcoma with metastasis in inguinal lymph nodes: Case report

Introduction. Aneurysmal bone cyst is a benign bone lesion composed of blood filled cystic cavities lined by fibrous septa. Its malignant transformation of is a rare event. Case report. We report a case of a lesion in the second metatarsal bone in a 29-year-old male, presented as a slight swelling of the right foot. After the curettage had been done, the diagnosis of aneurysmal bone cyst was made but the recurrence occurred 4 years later. The biopsy of the recurrent tumor showed compact neoplastic tissue consistent with diagnosis of giant cell tumor with malignancy. The malignant component was recognized as a high grade sarcoma with osteoid production. A tumor mass with the whole II metatarsal bone was extirpated and a resected part of fibula was transplanted. A year later, another recurrence occurred, an amputation was performed and a teleangiectatic osteosarcoma with ingvinal lymph nodes metastases was diagnosed. No other tumor mass was confirmed, either clinically or by imaging techniques at the time of his third operation. He died 4 months later with multiple pulmonary metastases. Conclusion. We emphasize the importance of team work in order to achieve the accurate diagnosis, highlighting careful radiological examinations, good sampling and awareness of unusual cases in bone tumor pathology.