Cytological findings of microfilariae in different sites: A retrospective review of 22 cases from endemic region.

Background: Filariasis is a major health problem in India. Despite the high prevalence, microfilariae are rarely found in cytology smears. Most of the cases are incidentally found, solely or in association with other pathologies.

Aims and Objectives: The study was undertaken to analyze the prevalence and cytology findings of cases of incidentally found microfilariae in cytology smears (fine-needle aspiration cytology [FNAC]/body fluids) from different body parts.

Materials and Methods: This was a retrospective study over 5 years, where the cases of microfilariae in aspirates from swelling of different locations and body fluids were reviewed, and clinic-pathological data were analyzed.

Results and Analysis: Out of 16,738 cases of FNAC and 882 cases of fluid cytology, 22 cases (0.124%) of incidental finding of microfilaria were documented in cytology smears. The cases were diagnosed from lymph nodes (5 cases), skin and soft tissue (4 cases), scrotal (4 cases), breast (3 cases), thyroid (2 cases), and pleural fluid (2 cases). We found eosinophilia in 15 cases (68.18%) of filarial lesions. We found two cases of incidental findings of microfilariae in association with malignant lesions.

Conclusion: Filariasis should be considered as differential diagnosis of swelling of lymph nodes, skin, soft tissue, inguinoscrotal region, and other sites as well. Careful screening of cytology smears may help in detection of incidental cases in the association of other pathologies.