Pulmonary Squamous Cell Carcinoma with Repeated Increases and Decreases in Size

抄録

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

CASE PRESENTATION: 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).

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