Fine-needle aspiration biopsy of chondroblastic osteosarcoma of the vertebral column complicated by Corynebacterium infection: a case report.

We describe a case of chondroblastic osteosarcoma of the vertebral column in a 67-yr-old male in whom the preoperative diagnosis was made by fine-needle aspiration biopsy (FNAB). This diagnosis was subsequently confirmed in the T8 corpectomy specimen. Although the smears of the aspirate revealed only occasional markedly atypical spindle-shaped nuclei, the cell block was diagnostic of malignancy. It showed a well-preserved fragment of neoplastic cartilage populated by markedly atypical hyperchromatic cells and a crushed fragment of anaplastic spindle-shaped cells surrounded by opaque collagenous matrix reminiscent of osteoid. The surgically resected specimen exhibited comparable histological features as well as colonies of gram-positive bacilli within the necrotic tumor. Culture confirmed the presence of Corynebacterium species. It is likely that these skin organisms were introduced at the time of FNAB. This case demonstrates the value of FNAB in the diagnosis of primary bone tumors and reports a rare complication of this procedure.