Dirofilariasis of breast: Report of two cases diagnosed by fine‐needle aspiration biopsy

Abstract

We report on 2 cases of dirofilariasis of the breast occurring in adult Chinese females residing in Hong Kong. The diagnosis was made by fine-needle aspiration biopsies. The direct smears contained numerous acute inflammatory cells, including eosinophils. A partially necrotic adult nematode of about 400-450 microm in diameter was identified in the cell-block sections of each case. The worm was characterized by a thick cuticle with longitudinal cuticular ridges and fine transverse surface striations, abundant somatic muscle, an intestine, and a reproductive tube or uterus. The morphologic features of this round worm were most compatible with those of Dirofilaria repens. While the clinical and radiologic findings of dirofilariasis of the breast are nonspecific and mimic those of breast neoplasms or inflammatory conditions, a definitive diagnosis is possible with fine-needle aspiration biopsy. A correct diagnosis of dirofilariasis may help to spare patients from unnecessary medical and surgical interventions.

A Novel Dirofilaria Species Causing Human and Canine Infections in Hong Kong

“…In Hong Kong, two cases of breast lesion due to D. repens based on morphological features have been reported (17). On the other hand, D. immitis is usually associated with pulmonary nodules (16).…”

Dirofilaria repens Diagnosed by the Presence of Microfilariae in Fine Needle Aspirates

“…Also none of the previous cytologic reports of dirofilariasis detected microfilariae or eggs on aspirated smears. [5][6][7] The present case was unique because of detecting microfilariae in material aspirated from a subcutaneous mass and later detecting gravid adult female Dirofilaria worms in histologic sections. The presence of many microfilariae in aspirated material indicated that the needle was inserted into the gravid uterus.…”

“…Four patients presented with breast masses, and others had retroperitoneal, facial and lung masses. [5][6][7] In none of them was dirofilariasis suspected before FNA. Also none of the previous cytologic reports of dirofilariasis detected microfilariae or eggs on aspirated smears.…”

“…[2][3][4] Few cytologic reports on dirofilariasis are based on detection of fragments of adult worm in cell blocks. [5][6][7] In this case the diagnosis was made on finding microfilariae outside the worm in fine needle aspirates and confirmed by the presence of the gravid worm in tissue sections. …”

Dirofilariasis in Russian Federation: a big problem with large distribution

“…Subcutaneous migration of the worm may result in local swellings with changing localisation (creeping eruption) [31]. In addition, rare cases of organ manifestation have been reported, affecting the scrotum, male genitals, female breast, lymphatic glands and peritoneum [2,[32][33][34][35][36][37][38]. OD is a variation of subcutaneous dirofilariasis with parasite localisation in the eye area [30].…”