Mycetoma can be accurately diagnosed in smears obtained by fine needle aspiration (FNA). Mycetoma lesion has a distinct appearance in a cytology smear characterised by the presence of polymorphous inflammatory cells consisting of an admixture of neutrophils, lymphocytes, plasma cells, histiocytes, macrophages and foreign body giant cells and grains.
In sections, the grain is closely surrounded by and occasionally infiltrated by neutrophils causing its fragmentation. Outside the neutrophil zone, monocytic cells and giant cells are seen. This is surrounded by granulation tissue rich in fibroblasts and blood vessels.
The technique allows morphological identification of mycetoma and its classification into eumycetoma and actinomycetoma, this is important as the treatment depends mainly on the aetiological agents.
The technique is simple, cheap, rapid, sensitive and can be tolerated by patients. It can be used not only in routine diagnosis but can be used as an effective mean in collection of material for culture and immunological studies. Due to the simplicity of the technique, it can be used in epidemiological survey of mycetoma and for detection of early cases in which the radiological and serological techniques may not be helpful.