In tropical countries like India, filariasis is a common health problem. India alone accounts for nearly one-third of the world's population at risk for lymphatic filariasis. Filariasis can be caused by nematodes such as Wuchereria bancrofti, Brugia malayi, Brugia timori, Loa loa, and many more. In India, filarial infection is mainly caused by two similar nematodes Wuchereria bancrofti and Brugia malayi.[1,2] Man is the definitive host of this parasite. Filariais is transmitted by female Culex mosquito. In the mosquito, microfilariae develop into an active form and get transmitted to the definitive host when the mosquito bites them. Although the disease mainly affects lymphatic channels and lymph nodes the microfilariae are not just confined to the lymphatic system and may involve other organs and serous cavities.[3] Breast is an uncommon extranodal site for filariasis which can present as a unilateral painless solitary superficial non-tender breast mass, usually in the upper and outer quadrant and can mimic a neoplasm.[4,5,6]
Cytology plays an important role in the diagnosis of filariasis presenting as palpable swellings. Diagnosis is mainly based on demonstrating microfilariae in the smears; however, incidentally, there could be numerous microfilariae with or without gravid worm or embryoid forms. Herein, we report a case of bancroftian filariasis presenting as a solitary subcutaneous breast lump, detected on unstained cytosmear evaluation demonstrating numerous microfilariae entangled with each other.
A 28-year-old woman presented with a painless lump in the right breast for the last 10 days. On examination a well-defined subcutaneous non-tender, soft, and freely mobile swelling measuring about 1.5 cm × 1 cm was present in the upper outer quadrant of the right breast. The overlying skin was unremarkable. Ultrasonography (USG) demonstrated an irregular, echo poor mass lesion at approximately 11 o'clock position and right axillary lymph node enlargement measuring 1.5 × 0.6 cm and 1.2 × 0.9 cm, respectively. Fine-needle aspiration yielded scant granular whitish material. Air-dried and wet fixed smears were prepared for May-Grunwald-Giemsa (MGG) and hematoxylin and eosin (H and E) staining, respectively. However, before submitting the smears for staining, as a routine protocol unstained smears were evaluated microscopically for cellular adequacy which revealed an entangled bunch of worms with likely diagnosis of filariasis. Microfilariae with slender nuclei laden bodies could be very well-identified in the unstained smears [Figure 1a and b]. Thereafter smears were stained with MGG and H and E stains, which also showed numerous ensheathed microfilariae with multiple somatic nuclei extending in the whole of the body except cephalic and tail ends [Figure 1f]. One of the smears also showed numerous embryoid forms and coiled microfilariae [Figure 1c-e]. The background showed a mixed inflammatory cell infiltrate. An FNA diagnosis of breast filariasis was given with filarial species morphologically identified as Wuchereria bancrofti.
Figure 1.
(a-b) Unstained fine-needle aspiration smears showing a fragment of gravid female adult worm with numerous microfilariae entangled with each other; (c) Fine-needle aspiration smear showing numerous microfilariae (H and E; ×20); d, Smear showing scattered embryoid forms of the parasite (H and E; ×10); (e) Smear showing the larva form of the parasite in an inflammatory background (H and E; ×20); (f) Smear showing ensheathed microfilaria of Wuchereria bancrofti with somatic nuclei in the center, not extending into the cephalic and the tail ends (MGG; ×40)
Fine-needle aspiration of breast lumps is a component of triple test and detection of filarial infestation in fine-needle aspirates is an incidental finding. Though stained FNA smears reliably demonstrate microfilariae, rapid on-site evaluation (ROSE) of unstained smears can also detect parasite morphology and triage FNA material for ancillary techniques if neoplastic pathology is suspected.
Ethical Approval
All procedures performed on patient tumor samples in this study were in accordance with the ethical standards of the institutional ethics committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Declaration of patient consent
Informed consent was obtained from all individual participants included in the study.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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