Bevacizumab-induced pulmonary cystic disease.

The use of Bevacizumab has significantly advanced the treatment of various malignancies. Bevacizumab's inhibition of angiogenesis is a known mechanism that impedes tumour growth and facilitates chemotherapy delivery; however, its association with the development of cystic lung disease is not fully understood. We report a unique case of a 73-year-old woman with a past medical history of metastatic endometrial adenocarcinoma status post-chemotherapy with bevacizumab that presented with worsening respiratory symptoms. A follow-up chest CT scan post chemotherapy showed the transformation of the metastatic lesions into cystic formations. After further extensive evaluation, she was diagnosed with pulmonary cystic disease secondary to bevacizumab. This case illustrates a rare presentation of secondary pulmonary cystic disease following Bevacizumab therapy in a patient with metastatic endometrial adenocarcinoma. It highlights the importance of recognizing uncommon side effects of targeted immunotherapy and underscores the need for ongoing research to understand the underlying mechanisms and manage such complications effectively.