# Pulmonary Squamous Cell Carcinoma with Repeated Increases and Decreases in Size

## TL;DR

A patient's lung cancer showed unusual size changes over four years, possibly due to immune responses, highlighting the need for careful monitoring.

## Contribution

This case report documents rare spontaneous tumor size fluctuations in pulmonary squamous cell carcinoma, suggesting possible immune system involvement.

## Key findings

- The lung nodule repeatedly increased and decreased in size over four years.
- A bronchoscopic biopsy confirmed squamous cell carcinoma.
- The tumor shrinkage may be linked to immune response activation.

## Abstract

Spontaneous regression of cancer is rare. Although the underlying mechanism is unknown, immunological responses are thought to be involved.

An 82-year-old Japanese man presented with an incidental bile duct tumor and a dilated common bile duct noted on computed tomography of the abdomen. The scan also showed a 1.1 cm snowball-like shadow in the right lower lobe of the lung. Subsequently, he developed obstructive cholangitis and underwent endoscopic retrograde biliary drainage. Over 4 years of follow-up, the lung nodule repeatedly increased and decreased in size, and new nodules appeared and disappeared. A bronchoscopic biopsy was then performed to evaluate an enlarged nodule, which was consistent with squamous cell carcinoma. He underwent right lower lobectomy with ND1b lymph node dissection. The final diagnosis was pulmonary squamous cell carcinoma (pT1cNXM0).

Immune response activation may have caused the observed tumor shrinkage. Careful follow-up is warranted owing to the possibility of regrowth.