Rapid Sarcomatoid Transformation of Lung Squamous Cell Carcinoma After Neoadjuvant Therapy: A Case Report

Pulmonary sarcomatoid carcinoma is a rare variant of non-small cell lung cancer. Here, we report on the case of a 67-year-old male with a diagnosis of biopsy-proven moderately differentiated squamous cell carcinoma of the left lower lobe of the lung. The tumor cells on biopsy had epithelioid morphology with strong immunoreactivity for CK7 and p40. The mass was surgically removed one year later due to its poor response to stereotactic radiotherapy and chemotherapy. The lobectomy specimen revealed pleomorphic mitotically active spindle cell neoplasm with scattered foci of epithelial component. The tumor cells showed diffuse immunopositivity for vimentin, as well as focal immunoreactivity for CK7, p40 and S100 in the epithelial component. To the best of our knowledge, this is the first documented case of histopathologic sarcomatoid transformation of lung squamous cell carcinoma after neoadjuvant therapy. The clinical course, diagnosis and a review of literature are presented.