[A complex case of miliary pulmonary tuberculosis following intravesical BCG therapy]

Bladder cancer (urothelial carcinoma in 90 % of cases) is the most common neoplasia of the urinary tract. Superficial carcinoma represents 70-80 % of bladder cancers. The treatment of these tumours includes, after transuretral resection, intravesical Bacillus Calmette-Guerin (BCG) instillation therapy. This treatment constitutes, by its immune-mediated anti-tumoral action, the first step of immunotherapy in cancer. Severe complications (granulomatosis, hypersensitivity pneumonitis or orchitis) are rare (0.5-2 %). Here we report a complex case of pulmonary granulomatosis secondary to BCG therapy. This is a 74-year-old male, treated for superficial bladder carcinoma by transuretral resection (pT1G3) and then endovesical instillations of BCG therapy for two months. Two years later, a new transuretral resection shows an infiltrating urothelial carcinoma pT2G3. The extension balance finds a persistent micro-nodular pulmonary infiltrate. A broncho-alveolar lavage is then realised but no mycobacteria was found. A surgical biopsy of a nodule is performed and revealed a histiocytic reaction without any neoplastic element. Detection of Mycobacterium tuberculosis by Polymerase Chain Reaction (PCR) was finally positive. In the absence of a secondary lesion, the patient had a cysto-prostatectomy and began a tritherapy against tuberculosis. Post-BCG therapy granulomatosis is a rare complication but should remain a differential diagnosis in front of the appearance of pulmonary nodes in patients who have received posttransuretral resection BCG instillations. Mycobacterial DNA PCR research remains the most sensitive examination.