Non-Small Cell Lung Cancer: A Rare Case Underscores the Importance of Remembering Uncommon Types

ABSTRACT

Introduction:Lung cancer is the leading cause of cancer death and the second most common cancer. Non-small cell lung cancer (NSCLC) is most common type, with adenocarcinoma and squamous cell carcinoma representing the most prevalent subtypes. Here, we present a case of a large lung mass which underscores the importance of considering rare types of lung cancer when formulating a differential diagnosis.Case ReportThe patient was 78-year-old man presenting one month after mild COVID-19 infection with persistent chest heaviness felt to be the sequalae of COVID-19. A review of symptoms was significant for appetite change, fatigue, cough, chest tightness, and unexpected weight change. Physical exam showed diminished left breath sounds. Pulmonary function tests showed an FEV1 of 54%;DLCO was not obtained. CT of the chest demonstrated an 11.3 x 7.2 x 15.6 cm necrotic mass of the left upper lobe. Further characterization with MRI demonstrated an 11.8 x 7.9 x 17.5 cm heterogeneously enhancing mixed signal mass with areas of either cystic degeneration or necrosis in the left hemithorax with loss of mediastinal and pericardial fat planes, suggestive of invasion (Figure 1, arrow). Prominent mediastinal lymph nodes and chest wall invasion were also identified. A small pleural effusion was present at that time (dashed arrow). MRI of the brain was negative for metastases. A biopsy was consistent with pulmonary sarcomatoid carcinoma, a rare type of NSCLC. The patient was treated with radiation.ImportancePulmonary sarcomatoid carcinoma is a rare type of non-small cell lung cancer accounting for 0.4% of cases which carries a poor prognosis and is not sensitive to chemotherapy, rendering surgery the best treatment option. Given that it is poorly differentiated, it is likely to present as a large mass with heterogenous signal and enhancement. Closely related differential considerations include diffuse sarcomatoid malignant mesothelioma and sarcomatoid carcinoma metastatic to lung. Other rare types of lung cancer include adenosquamous carcinoma, large cell neuroendocrine carcinoma, adenoid cystic and mucoepidermoid carcinomas of the lung, granular cell lung cancer, typical and atypical carcinoids. While rare, it is important to consider these less common types of non-small cell lung cancer in the differential diagnosis given differences in treatment options and prognosis.