Childhood Cancers Misdiagnosed as Tuberculosis in a High Tuberculosis Burden Setting

Tuberculosis (TB) and childhood cancers have overlapping presentations and malignancies may be misdiagnosed as TB in high TB-burden settings.

This retrospective study investigated the diagnosis of TB in children with cancer registered in the Tygerberg Hospital Childhood Tumor Registry from 2008 to 2018. We studied children on anti-tuberculosis treatment (ATT) at cancer diagnosis or diagnosed with TB within 1 month of cancer diagnosis. We describe the circumstances and extent of this misdiagnosis, quantify the delay in therapy and document the outcomes of these children.

Twenty-seven of 539 (5%) children in the registry started ATT before cancer diagnosis. Both pulmonary and extrapulmonary TB complicated the cancer diagnosis. Of the 27 patients on ATT at cancer diagnosis, 22 (81%) had contact with a TB case and in 6 of 12 children (50%) a tuberculin skin test was positive. At cancer diagnosis, 16/27 (59%) children had chest radiograph changes interpreted as TB with 11/27 (41%) regarded as suggestive of TB on expert review. The median diagnostic delay between TB and cancer diagnoses was 25 days (interquartile range 3.5-58). Of 539 children with cancer, 204 (38%) died of cancer, including 18/30 (60%) children on ATT at cancer diagnosis or diagnosed with TB within 1 month of cancer diagnosis (odds ratio 2.6; 95% confidence interval: 1.2-5.4; P = 0.012).

The clinical and radiologic overlap of TB and cancer causes diagnostic confusion in a significant number of children with cancer and may contribute to increased mortality.