Whole-Process Treatment of Combined Small Cell Lung Cancer Initially Diagnosed as Lung Squamous Cell Carcinoma: A Case Report and Review of the Literature

The rarity and complexity of histology lead to the low diagnosis rate and high misdiagnosis rate of combined small cell lung cancer (C-SCLC). Nowadays, C-SCLC has no commonly recommended therapeutic regimen, mainly conforming to SCLC treatment. Here, we report a patient initially diagnosed as IIIA lung squamous cell carcinoma by a small specimen. Radical resection was achieved after neoadjuvant immunochemotherapy, and the final surgical pathology was C-SCLC containing three different histological components. Moreover, in the literature review, we explored the therapeutic effect of neoadjuvant immunotherapy in C-SCLC, expounded the therapeutic conflicts among heterogeneous components, and analyzed the pathology complexity at the tissue, cell, and molecule levels in-depth, including possible genetic characteristics, origin, and evolution by next-generation sequencing (NGS).

Automated summary

The rarity and complexity of histology lead to the low diagnosis rate and high misdiagnosis rate of combined small cell lung cancer (C-SCLC). Currently, there is no commonly recommended therapeutic regimen for C-SCLC, and it mainly conforms to SCLC treatment. We report a case of a patient initially diagnosed as stage IIIA lung squamous cell carcinoma who underwent radical resection after neoadjuvant immunochemotherapy, and the final surgical pathology showed C-SCLC containing three different histological components. Our literature review explores the therapeutic effect of neoadjuvant immunotherapy in C-SCLC, explains the therapeutic conflicts among heterogeneous components, and analyzes the pathology complexity at the tissue, cell, and molecule levels in-depth, including possible genetic characteristics, origin, and evolution through next-generation sequencing (NGS).