Polymerase chain reaction-based detection ofMycobacterium tuberculosisDNA in formalin-fixed, paraffin-embedded skin tissue specimens from Filipino patients

A Case of Tuberculous Granulomatous Panniculitis without Vasculitis

We report a case of tuberculous granulomatous panniculitis without vasculitis in an 87-year-old female patient with B-cell chronic lymphocytic leukaemia. One month after starting chemotherapy with chlorambucil and prednisone she presented superficial erythematous plaques on the anterior side of the left leg. Three weeks later erythematous painless deep nodules appeared on the left popliteal fossa and on the left thigh. Cutaneous biopsy revealed granulomatous panniculitis without caseation necrosis or vasculitis. Polymerase chain reaction for Mycobacterium tuberculosis revealed positivity in the skin. The final diagnosis was reactivation of latent tuberculosis (TB) induced by deep immunosuppression associated with chemotherapy and haematological disease. Tuberculous granulomatous panniculitis without vasculitis is a rare presentation of cutaneous TB and may be part of the heterogeneous histopathologic spectrum of erythema induratum of Bazin (nodular vasculitis). Our case shows that the diagnosis of cutaneous TB requires the correlation of clinical findings with histopathology and microbiological tests.

Diagnosis of extrapulmonary tuberculosis by PCR

During the last two decades, the resurgence of tuberculosis (TB) has been documented in both developed and developing nations, and much of this increase in TB burden coincided with human immunodeficiency virus (HIV) epidemics. Since then, the disease pattern has changed with a higher incidence of extrapulmonary tuberculosis (EPTB) as well as disseminated TB. EPTB cases include TB lymphadenitis, pleural TB, TB meningitis, osteoarticular TB, genitourinary TB, abdominal TB, cutaneous TB, ocular TB, TB pericarditis and breast TB, although any organ can be involved. Diagnosis of EPTB can be baffling, compelling a high index of suspicion owing to paucibacillary load in the biological specimens. A negative smear for acid-fast bacilli, lack of granulomas on histopathology and failure to culture Mycobacterium tuberculosis do not exclude the diagnosis of EPTB. Novel diagnostic modalities such as nucleic acid amplification (NAA) can be useful in varied forms of EPTB. This review is primarily focused on the diagnosis of several clinical forms of EPTB by polymerase chain reaction (PCR) using different gene targets.