Background: Sarcomatoid carcinoma (SC) is a rare, aggressive, and heterogeneous subtype of non-small cell lung cancers. Once the cancer is diagnosed, surgical resection followed by chemotherapy or radiation is the general line of treatment based on the staging. Case Presentation: We report a case of a young female who presented with 1-week history of shortness of breath and found to have a mass in the lung. She was diagnosed with SC, but resection was not possible because of the cancer size. The patient’s clinical status deteriorated as the mass increased in size so rapidly that she died within 18 days of the first evaluation. Conclusion: Unlike other lung cancers, SC can show aggressive deterioration within a matter of days. When suspected, early evaluation and diagnosis are warranted for the timely treatment of SC.

Keywords: Lung cancer, non-small cell lung cancer, sarcomatoid carcinoma