Tension Pneumothorax: Is it Sarcoma or Pazopanib?

Abstract

Synovial sarcomas are rare malignant tumors that originate from primitive pluripotent mesenchymal stem cells that look similar to the developing synovium, but are histologically unrelated to it. Sarcomas commonly metastasize to the lungs and surrounding pleura, with a documented incidence as high as 85% for pleural-based metastases. The incidence of spontaneous pneumothorax in patients with sarcomas is only 1.9%, with synovial sarcoma being the third most common type of sarcoma associated with pneumothorax. While surgical resection is usually the treatment for localized primary synovial cell sarcoma, metastatic disease requires systemic therapy, mainly chemotherapy. Failure of chemotherapy calls for the use of targeted therapeutic agents such as pazopanib. Pazopanib has been linked to the incidence of spontaneous pneumothorax in previous case studies. However, primary research fails to establish a statistically significant causal association. Research shows that pneumothorax can result from lung metastases independent of therapeutic side effects. We report a case of synovial sarcoma of trapezius origin with secondary lung metastases, and development of pneumothorax after pazopanib treatment. We discuss the incidence of pneumothorax as a medication side effect versus independent effect of natural disease progression, and how this plays role in deciding when to continue using a medication in the face of complications.

Keywords: pazopanib; pneumothorax; synovial sarcoma; trapezius.

Figure 1. CT scan of axial section showing left pleural nodule (red arrow) and left trapezius muscle mass (blue arrow)

Figure 2. CT scan of axial section showing left lower lobe nodule (blue arrow)

Figure 3. CT scan of sagittal section showing left trapezius muscle mass (white arrow)

Figure 4. CT scan of axial section showing loculated malignant fluid collections compressing most of left lung and right lung base (arrowheads) with scattered lobular sarcomatous masses (arrow)