# Spontaneous Resolution of Miliary Pulmonary Nodules Following Intravesical Bacillus Calmette-Guérin (BCG) Therapy: A Case Report and Literature Review

## TL;DR

A man developed lung nodules after BCG therapy for bladder cancer but improved without treatment, suggesting observation may be safe in some cases.

## Contribution

This case report highlights the possibility of spontaneous resolution of BCG-induced pulmonary nodules without antimycobacterial therapy.

## Key findings

- A patient with miliary pulmonary nodules after BCG therapy showed spontaneous improvement without treatment.
- Bronchoalveolar lavage cultures were negative for Mycobacterium bovis.
- Clinical stability and lack of systemic symptoms supported a conservative management approach.

## Abstract

Intravesical Bacillus Calmette-Guérin (BCG) immunotherapy is a well-established treatment for non-muscle-invasive bladder cancer. Although it is typically associated with local irritative symptoms, rare systemic and pulmonary complications can occur, including hypersensitivity pneumonitis and miliary tuberculosis.

We report the case of a 70-year-old man who developed diffuse miliary pulmonary micronodules and ground-glass opacities after his 12th BCG instillation. Despite imaging findings suggestive of disseminated infection, the patient remained clinically stable, without fever, hypoxia, or systemic deterioration. Bronchoalveolar lavage cultures were negative for Mycobacterium bovis. A shared decision was made to withhold antimycobacterial therapy and monitor closely. Follow-up imaging revealed spontaneous improvement without treatment.

This case underscores that observation may be appropriate in selected stable patients without systemic signs of infection. Careful clinical assessment and individualized management are essential to avoid unnecessary therapy and ensure patient safety.