Pulmonary Tuberculosis Versus Recurrent Chemotherapy-Induced Pneumonitis: A Clinical Dilemma.

Chemotherapy-induced lung toxicity can affect pulmonary parenchyma, pleura, airways, pulmonary vascular system, mediastinum or the neuromuscular system that is responsible for respiration. Chemotherapy-induced pulmonary toxicity is a diagnosis of exclusion. When the patients with malignancies develop pulmonary toxicity such as pneumonitis and distinguishing it from alternative diseases such as infectious, thrombotic, cardiac, malignant or exacerbation of chronic lung conditions can be difficult. Moreover, such patients are often immunosuppressed, physically stressed from the underlying disease and the cancer treatment and hence, more susceptible to usual and unusual or opportunistic infections. We describe a patient with pancreatic cancer who was assumed to develop recurrent chemotherapy-induced pneumonitis to various agents, including irinotecan and docetaxel, but subsequently proved to have reactivation of tuberculosis (TB). With tuberculosis not being uncommon in cancer patients, we now believe that his symptoms could all have been because of an active tuberculosis infection, especially with his latent TB history and pulmonary symptoms. Information about the link between the treatment of solid-organ cancers and TB is very limited. Our case underlines the recognition about this link of chemotherapy and TB as well as remind us of the lack of widely accepted and established standards for both screenings for latent TB and for the treatment of active TB in the patients undergoing systemic treatment. A simple test such as a tuberculin skin test or QuantiFERON-TB Gold test can be used to rule out latent TB before beginning radiotherapy or chemotherapy in these patients. Clinicians must be cognizant of this condition to prevent further morbidity and mortality in these cancer patients and include activated TB in the differential diagnosis of pulmonary toxicity suspected in a patient undergoing chemotherapy with unexplained pulmonary findings.