Abstract

We recently experienced an atypical chondroid lesion metastatic to the lung. Examined under the microscope, the excised nodules displayed abundant amounts of chondroid tissue and necrosis with dystrophic calcification. The calcification had a characteristic "chicken wire" pattern. The chondroblasts contained one or two round to oval, focally indented nuclei with inconspicuous nucleoli. Although some enlarged nuclei with mild to moderate pleomorphism were present, significant nuclear atypia was lacking. Mitotic figures were scarce (1/10 high power field). Scattered multinucleated osteoclast-type giant cells were observed among the chondroblasts. Thus, the possibility of chondroblastoma was considered first. Metastasis of histologically benign chondroblastoma is a rare event, but well documented. The pulmonary metastatic nodules were described as ceasing to grow in some cases; and a significant number of patients were free of tumors following removal of the metastatic nodules. These findings suggest that the metastasis may represent a simple transport phenomenon. However, there are, as yet, no histologic parameters that help determine whether these metastases are to cease their growth or will progress to kill the host.

• Keywords: Metastasis;Chondroblastoma;Lung