Tuberculosis 'The Great Imitator': A usual disease with unusual presentations.

BACKGROUND: A number of infectious diseases have been referred to by the phrase 'The Great Imitator', of which the oldest is syphilis; others include Lyme disease, nocardiosis, etc. Tuberculosis has been described as the second great imitator as it can imitate various other disease processes. An awareness of the atypical clinical manifestations of tuberculosis is important, especially in regions where tuberculosis continues to be a major public health problem, such as India. Extrapulmonary tuberculosis (EPTB) constitutes about 15-20% of all cases of tuberculosis in immunocompetent patients and accounts for more than 50% of the cases in human immunodeficiency virus (HIV)-positive individuals.

METHODS: We hereby report 4 cases of tuberculosis at unusual sites, which were not suspected clinically and were subsequently diagnosed by pathological examination and by ancillary techniques.

OBSERVATIONS AND RESULTS: In all the four cases, the involvement was extrapulmonary in nature and at unusual sites. Three cases were diagnosed by a positive Ziehl Neelsen stain while culture for Mycobacterium tuberculosis was positive in three cases. All the four patients tested negative for HIV status on serology.

CONCLUSIONS AND IMPLICATIONS: Unusual presentations, which mimic many diverse conditions, as seen in this series, highlight the importance of a high index of suspicion in the timely diagnosis of tuberculosis. Evidence of systemic or lung involvement may not always be present and laboratory and radiological findings play an important role.