Primary sarcomatoid carcinoma of the lung

Primary sarcomatoid carcinomas of the lung refer to a heterogeneous group of rare and poorly differentiated types of non-small cell lung carcinomas (NSCLC).

Epidemiology

They are thought to account for 0.2 to 1% of all lung cancers ¹. Sarcomatoid histology may be present in 0.1-0.4% of non-small cell lung cancers ³. 

Pathology

They are poorly differentiated non-small cell cancers that contain a sarcoma or sarcoma-like component. They are the most common pulmonary neoplasms that exhibit a composition by spindled or pleomorphic tumor cells. Due to this reason, they may be confused easily with true sarcomas diagnostically unless special immunohistological or ultrastructural analyzes are performed.

Subtypes

Specific subgroups that have been classified under sarcomatoid carcinomas of the lungs include ^4,6:

• pleomorphic carcinoma of the lung (most common >50%) ¹⁰
• spindle cell carcinoma of the lung
• giant cell carcinoma of the lung
• carcinosarcoma of the lung
• pulmonary blastoma

Treatment and prognosis

While some publications suggest a poorer prognosis with sarcomatoid histology ³ although this fact appears to be debatable according to other publications ¹.

Differential diagnosis

If sarcomatoid histology is revealed following a biopsy for a lung lesion, differentials to consider include ⁷:

• diffuse sarcomatoid malignant mesothelioma involving the lung: likely to have an associated pleural component
• metastatic sarcomatoid neoplasm to lung

See also

• sarcomatoid tumors of the thorax