Sixty-three lymph node aspirates were screened and 32 aspirates revealing granulomatous lymphadenitis with or without caseation necrosis were re-evaluated. The most characteristic morphological features among these cases were epithelioid cell clusters with or without caseation necrosis. When clusters were thick, careful observation of the periphery of the clusters helped to find epithelioid cells. Caseation necrosis revealed a typical macroscopic and microscopic appearance. Ziehl-Neelsen staining was negative in all smears and histological sections. Polymerase chain reaction (PCR) amplification technique was applied to 23 of the cases in which the cytological diagnoses were consistent with tuberculosis. Mycobacterium tuberculosis was demonstrated in 19 (82.60%) cases.
In conclusion: (i) it is necessary to perform several aspirations from different sites of the enlarged lymph node; (ii) the diagnosis of 'granulomatous lymphadenitis, consistent with tuberculosis' can be given, even though the acid-fast stains are negative; (iii) additional techniques such as PCR give supportive information; (iv) an open biopsy is recommended if there is a discrepancy with the clinical impression.