Non-caseating Granulomas in patient with bladder cancer

70 M PMH MM, bladder Ca presents w/ weeks of fatigue, fever, cough, intermittent hemoptysis, wbc3, plt120, Hb9, b/l pulm infiltrates, non-caseating granuloma. diagnosis?

Disseminated Mycobacterium bovis infection. +hx of transitional-cell carcinoma of bladder s/p intravesiclular BCG. BCG is a live attenuated strain of M. bovis. Systemic complications are rare <1% include b/l interstitial pneumonitis & non-necrotizing granulomas

Pathogenesis is incompletely understood but thought that organisms gain access to lymphatics & blood via disruption of uroepithelium & then disseminate to multiple sites. Granulomatous rx can occur. indistinguishable from MTB

Ddx: Bacterial, viral, fungal & other mycobacterial dz can cause F cough & hemoptysis but patient’s clinical course was not consistent with typical bacterial or viral pneumonia & granulomatous inflammation is not a feature of these infections. BC/BAL culture neg, RVP neg, CMV neg

Ddx: Hypersensitivity pneumonitis: +F malaise, wt loss & cough but hemoptysis is uncommon. pt had neg precipitating IgG Ab against potential antigens. A positive serum test for precipitins can be helpful in confirming dx but a negative test should not be used to rule it out

Ddx: fungal pulmonary granulomas: cryptococcus, histoplasma, coccidioides & blasto. Presentation is most consistent w/disseminated or progressive infection not adequately contained by immune system. In such cases granuloma is uncommon & blood, sputum/BAL should have been +

Ddx: other NTM: Fever & weight loss are also less common in cases of NTM infection than in cases of tuberculosis

M. bovis rifampicin, isoniazid and ethambutol Treatment duration is generally extended to 9 months due to the exclusion of pyrazinamide, since all strains of M. bovis are resistant to it.

Originally tweeted by Indiana University Infectious Diseases Fellowship (@IUIDfellowship) on 15 December, 2020.

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