A Case of Breast Filariasis Diagnosed on Fine Needle Aspiration Cytology

Abbreviations

FNAC- Fine Needle Aspiration Cytology

Introduction

Lymphatic filariasis is a neglected tropical disease that causes severe disability and illness, primarily affecting impoverished communities with limited access to healthcare and sanitation. Filariasis is a chronic mosquito-borne parasitic infection with species of nematode parasites [1]. Filariasis is a widespread global health issue that results in socioeconomic instability in tropical regions across Asia, Africa, and South America [2-4]. In Ethiopia, lymphatic filariasis is particularly prevalent in the Gambella region, located in the western part of the country, with a reported prevalence rate of 3.7%. However, the prevalence in other regions of Ethiopia has not been well documented [5,6]. Filariasis primarily targets the lymphatic system, presenting with lymphedema and hydrocele [1]. Even if it is uncommon, filariasis has extra-lymphatic manifestations [7,8]. Among extra-lymphatic manifestations, breast involvement by filariasis is one of them with few documented case reports [9–11]. Fine needle aspiration cytology (FNAC) is a useful diagnostic method for detecting various stages of the infection. It usually identifies intact adult worms, microfilaria, embryonated eggs of gravid female worms, fragments of adult worms, and a mix of inflammatory cells, including eosinophils, lymphocytes, and occasionally granulomas [12,13].

Case History/Examination

A 55-year-old female patient from a rural area in northern Ethiopia presented with a complaint of a left breast lump and pain for 4 months. She also reported intermittent fever, generalized malaise, discharge from the swelling site, and a history of itching. Physical examination revealed a soft to firm, mobile subcutaneous mass in the left breast's upper outer quadrant. The overlying skin was erythematous, indurated, ulcerated, and oozing yellowish discharge (Figure 1). We noted multiple small, soft, mobile ipsilateral axillary lymph nodes, with the largest measuring 7 x 7 mm. The examination of the contralateral breast was unremarkable, with no history of nipple discharge or extremity edema. Her past medical and surgical history was unremarkable.

Methods (Differential Diagnosis, Investigations, and Treatment)

A left breast ultrasound examination showed a 14 x 12 x 12 mm measuring well-defined irregular hypoechoic lesion with a surrounding hyperechoic rim in the upper outer quadrant within the peri-mammary subcutaneous layer, with a final impression of a subcutaneous abscess. The complete blood count showed a white blood cell count of 5.26 K/µL with elevated eosinophils (8% of total white blood cells and an absolute eosinophil count of 420 cells/µL). Eosinophilia was also confirmed by the peripheral blood film. Hemoglobin and platelet counts were within normal ranges. FNAC was conducted using a 21-gauge needle attached to a 5 ml disposable syringe, which yielded a yellowish pus. The aspirate was then smeared onto a slide, air-dried, and stained with Giemsa stain. Microscopic examination of the stained slides revealed intact adult worms, embryonated eggs of gravid female worms, fragments of the worms, and a mixture of inflammatory cells (Figures 2A-C). The primary impression of the caring physician was breast carcinoma, which is excluded after the cytology examination which did not reveal features of neoplastic condition.

Figure 1: Clinical Image of The Breast Lesion

Figure 2: Cytologic Pictures

A and B: Adult Filarial Worm. C: Head of the Adult Filarial Worm.

Conclusions and Results (Outcome and Follow-Up)

We managed the patient with oral ivermectin and discharged her after a follow-up appointment. Although Diethylcarbamazine was our first choice, it was not available in our hospital. Upon follow¬up appointments the breast lump, skin induration, discharge as well as the generalized malaise and fever is resolved.

Discussion

Filariasis is most commonly observed in Asia, especially in India, constituting about 20% of the total global burden [13]. Though filariasis is widespread globally, finding filarial worms in cytological smears is very rare [14]. The parasite primarily affects the lymphatic system, with clinical manifestations typically seen in the lower limbs, spermatic cord, and testis [1]. Filariasis has been reported in different extra-lymphatic organs, including the breast, thyroid, and epididymis, and infrequently, it can also be detected in soft tissue swellings, bone marrow, gynecologic smears, liver, and body cavity fluids [7,11,12,15]. Breast filariasis is rare, and when it does occur, the upper outer quadrant of the breast is the most frequent site, though it can affect any quadrant [9,11,16]. In this case, the filariasis was identified in the upper outer quadrant of the left breast.

Breast nodules due to filarial infestation are rare and can occasionally mimic malignant lesions [17,18]. In this case, the ulcerated nodule initially raised concerns about breast carcinoma. However, FNAC revealed fragments of adult worms, embryonated eggs of female worms, and a mix of inflammatory cells, which helped to settle the diagnosis of breast filariasis. In conclusion for patients presenting with breast nodules in filariasis-endemic areas, filarial nodules should be considered a differential diagnosis. Fine needle aspiration cytology is a crucial diagnostic tool for diagnosing filariasis and can help avoid unnecessary surgical procedures.

Acknowledgments

The authors have no acknowledgments to make.

Funding Information

The study did not receive any form of grant or funding from profit or non-profit agencies.

Conflict of Interest Statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Consent

Written informed consent was obtained from the patient for anonymized patient information to be published in this article.

Ethics Statement

This is a case report and therefore did not require ethical approval from the ethics committee

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