Tubercular dactylitis: Fine needle aspiration cytology as a diagnostic modality

To evaluate the efficacy of aspiration cytology in the early diagnosis of tuberculous dactylitis and describe the spectrum of cytomorphologic features in these cases.

We studied 12 cases of dactylitis diagnosed as of tubercular etiology by fine needle aspiration cytology (FNAC) over a period of 6 years and assessed the clinicoradiologic features. The stained slides were reviewed and the spectrum of features noted.

The most common clinical presentation was an indurated swelling of the involved digit (100%). On radiography, most often an expansile, lytic lesion along with soft tissue swelling was noted in 83% of cases. However, the clinical diagnosis did not consider a tubercular (TB) etiology. FNAC of these cases showed variable features; the most common was granulomas with or without necrosis (75% in total). Two cases showed acute suppurative cytology, and 1 revealed only fibroblasts and afew neutrophils. On the basis of suspicion, staining for acid-fast bacilli (AFB) was done in all cases, and bacilli were identified in all of them after a thorough search. These patients were soon started on antituberculous therapy, with significant improvements.

FNAC can serve as an inexpensive and comparatively less invasive procedure for early diagnosis of TB dactylitis, permitting timely initiation of specific therapy. This study also highlighted the unusual cytomorphology in some cases. Clinicians and pathologists should maintain a high index of suspicion in cases of dactylitis and stain for AFB in all cases.