Chest Wall Chondrosarcoma

Abstract

A 75-year-old man presented with pleuritic chest pain and right shoulder pain. A palpable right anterior chest wall mass was noted on physical examination. His past medical history was significant for testicular cancer treated with radiation therapy in 1974. A computed tomography (CT) scan of the chest, performed without intravenous contrast due to renal insufficiency, revealed an 8-cm lobulated soft tissue mass arising from the right third anterior rib and involving the costal cartilage (Figure ​(Figure11). Scattered internal calcific deposits were present. It was uncertain if these represented chondroid matrix or destruction of calcified costal cartilage. The mass extended into the chest wall with elevation of the pectoralis muscles. Medially, the mass abutted the right anterior mediastinum. No additional osseous lesions or enlarged mediastinal or hilar nodes were seen. A few nonspecific 1- to 2-mm noncalcified pulmonary nodules were noted. CT of the abdomen and pelvis showed no evidence of metastatic disease. Figure 1 CT images through the chest at the level of the carina in both (a) soft tissue and (b) bone windows demonstrate a lytic mass involving the right anterior third rib, centered at the costochondral junction. A large, lobulated soft tissue component elevates ... Given the internal calcifications, the leading differential diagnostic consideration was chondrosarcoma; however, the classic “ring and arc” calcifications described in chondroid neoplasms were not definitively present on imaging. Metastasis was another consideration given the patient's history of testicular cancer; however, the location and appearance would be very atypical. The lesion appeared to arise from the chest wall and not the lung itself. Other considerations would include extramedullary plasmacytoma or lymphoma. An ultrasound-guided needle biopsy of the lesion, prepared for rapid cytologic evaluation using hematoxylin and eosin, showed a myxoid chondroid matrix with chondrocytes present (Figure ​(Figure22). The subsequently prepared paraffin block from the core biopsy showed a similar chondroid matrix with increasing cellularity at the periphery of the nodule (Figure ​(Figure33). Though no distinctly atypical chondrocytes were seen, the cellularity was concerning for a possible low-grade chondrosarcoma, and the tumor was excised along with the second, third, and fourth ribs. Grossly, the tumor did not involve the lateral margins but was 12 mm from the inferior resection margin of the fourth rib and 3 mm from the periosteal soft tissue of the superior aspect of the second rib. The neoplasm clearly demonstrated cartilage synthesis, as well as areas of hemorrhage and necrosis (50% of total tumor volume) (Figure ​(Figure44). Figure 2 Scrape preparation at time of ultrasound-guided biopsy demonstrating a myxoid chondroid matrix, increased cellularity, and chondrocytes. Diff-Quik stain, (a) ×100, (b) ×400. Figure 3 Paraffin cell block prepared from ultrasound-guided biopsy showing focal increased cellularity, chondroid matrix, and chondrocytes. Hematoxylin and eosin stain, (a) ×40, (b) ×100. Figure 4 Gross images of the resected tumor, showing the lesion (a) anteriorly, (b) posteriorly, (c) in cross-section, and (d) invading and destroying the third rib. Microscopically, the tumor showed features suggesting increasing histologic grade, such as areas with distinct marked hypercellularity, increasing nuclear size/atypia, and multinucleated cells (Figure ​(Figure55). However, the proliferation index, as demonstrated by MiB-1, was low, with most areas demonstrating 1% and focal areas demonstrating 5%. The tumor expanded the medullary cavity and in areas extended beyond the cortex, forming subpleural nodules posteriorly and involving the chest wall tissue anteriorly. The anterior chest wall surgical resection margin was focally involved by tumor. Extension through the pleural surface was not seen. Focal vascular invasion was present, with tumor grossly and microscopically surrounding and invading one blood vessel specifically. The tumor was considered grade 2. Figure 5 (a) Subpleural tumor nodule (×100). (b) Tumor at anterior resection margin (arrow) (×40). (c, d) Tumor expanding marrow cavity with markedly increased cellularity, nuclear atypia, and occasional multinucleated cells (×400). (e) ... Given the positive margin, radiation therapy was recommended. The patient received 3060 cGy of the planned 5940 cGy of radiation but could not complete the full course due to locoregional side effects. No additional therapy was recommended. A CT scan performed approximately 2 months after radiation therapy showed expected radiation changes and minimal pleural fluid without overt evidence of tumor recurrence. The patient is currently 4 months postradiation.