# Rare Combined Small-Cell Lung Carcinoma With Lymph Node Metastasis Exclusive to the Small-Cell Component: A Case Report

## TL;DR

This case report describes a rare lung cancer subtype with aggressive behavior and highlights the need for accurate diagnosis and individualized treatment.

## Contribution

The report presents a rare case of combined small-cell lung carcinoma with unique metastatic patterns and emphasizes diagnostic challenges.

## Key findings

- The tumor was composed of 70% squamous cell and 30% small-cell carcinoma with high Ki-67 (60%).
- Nodal metastases were exclusive to the small-cell component, and early post-operative recurrence occurred.
- Surgical specimens are critical for accurate diagnosis due to sampling limitations in small biopsies.

## Abstract

Combined small-cell lung carcinoma (C-SCLC) is a rare histological subtype characterized by the coexistence of small-cell and non-small-cell components, posing diagnostic and therapeutic challenges due to its heterogeneity and aggressive course. We report the case of a 65-year-old heavy smoker who presented with dyspnea and cough. Imaging revealed a right lower lobe mass, and he underwent pneumonectomy. Pathology showed C-SCLC composed of 70% squamous cell carcinoma and 30% small-cell carcinoma (Ki-67: 60%), with vascular invasion, pleural and bone infiltration, and nodal metastases (pT3N1Mx). Early post-operative recurrence with pleural and osseous metastases was observed, and cisplatin-etoposide chemotherapy was initiated. This case illustrates the poor prognosis of C-SCLC, often undetected on small biopsies due to sampling limitations, and underscores the importance of surgical specimens for accurate diagnosis. Given the absence of standardized treatment protocols, management requires a multidisciplinary and individualized approach.