Practical use of polymerase chain reaction for the diagnosis of steroid induced tuberculous lymphadenitis

Tuberculous lymphadenitis that had developed after treatment with systemic prednisolone was diagnosed using the polymerase chain reaction (PCR) combined with dot-blot hybridization. Although the patient had no history of tuberculosis or suggestive radiological findings, a DNA fragment specific for Mycobacterium tuberculosis complex strains was amplified from a paraffin-embedded biopsy specimen of a cervical swelling, which was compatible with tuberculous lymphadenitis on haematoxylin-eosin (HE) and Ziehl-Neelsen staining. This report demonstrates the practical use of PCR for diagnosis of extra-pulmonary tuberculosis in a case difficult to diagnose conventionally.