[Cutaneous tuberculosis: a case of difficult classification]

We describe a case of cutaneous tuberculosis in a 25-year-old Philippine man. Erythematous papulo-nodular lesions, measuring 0.5 to 1 cm, were present on lower limbs; a 2 cm nodule was located on the left flank. The examination of the skin biopsy showed the presence of a superficial and deep perivascular dermatitis with histiocytes, lymphocytes and plasma cells. Ziehl-Nielsen stain for mycobacterium were negative, while the cultural examination led to the isolation of M. tuberculosis. Direct smear and cultural examination of sputum for M. tuberculosis were negative; chest and skeletal roentgenograms, syphilis and HIV infection serology, haematological and hematochemical examinations and urinalysis were negative. Specific treatment with isoniazid, rifampin and ofloxacin led to a rapid remission of cutaneous lesions. This case was particularly difficult to classify, but the Authors think it would be considered a tuberculid.