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.