ALK-positive anaplastic large cell lymphoma undiagnosed in a patient with tuberculosis: a case report and review of the literature.

BACKGROUND: Due to a similarity between the features of lymphoma and the features of tuberculosis, lymphoma may go unrecognized and undiagnosed in patients with tuberculosis.

CASE PRESENTATION: A 33-year-old Thai man presented to our center with typical clinical manifestations of tuberculous lymphadenitis, with negative tests for both acid-fast bacilli and fungi, and negative polymerase chain reaction for Mycobacterial tuberculosis complex. The disease was not responding to anti-tuberculosis treatment and he developed both pericardial effusion and progressive lymphadenopathy. Large lymphoma cells were evident in the pericardial effusion, and a review of the previous lymph node biopsies confirmed the existence of ALK-positive anaplastic large cell lymphoma and tuberculous lymphadenitis. Moreover, when the tests were repeated, he was found to be positive for both acid-fast bacilli and Mycobacterial tuberculosis complex. The presence of typical morphology of tuberculous lymphadenitis and inattentional blindness may explain why the presence of large lymphoma cells was overlooked in one of the previous lymph node biopsies. Our patient developed severe pneumonia with profound septic shock due to carbapenem-resistant Enterobacteriaceae and died within days.

CONCLUSIONS: Given that tuberculosis and lymphoma can share common features, this case highlights the importance of thoroughly reviewing all foregoing relevant patient data (most notably pathology samples) in order to rule out the presence of lymphoma that may exist within the shadow of typical morphology of tuberculous lymphadenitis.