Dirofilariasis of the breast: Sonographic appearance

Abstract

Human dirofilarial infections characteristically manifest as pulmonary "coin" lesions or as subcutaneous nodules. A case of subcutaneous Dirofilaria infection of the breast involving a 25-year-old woman with a painful breast lump is presented. The patient had not traveled anywhere and did not have any animals, but provided a history of being bitten by mosquitoes. The suspicion of a parasitic infection was raised by the presence of rod-like structures within a hypoechoic nodule on sonography; movement within the nodule was detected during the examination. Histopathological examination revealed viable, adult female Dirofilaria repens, a nematode that is commonly found in dogs, cats, and wild mammals throughout parts of Europe, Africa, and Asia. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 42:433-435, 2014.

Recent advances on Dirofilaria repens in dogs and humans in Europe

“…Nodules have been reported in various human body areas and tissues, mostly in the superficial tissues of the facial regions [1, 8], as perioral and periorbital tissues [107, 167, 224, 226, 227, 229–234], forehead [235], skin of the lower leg [93], soft tissues of the hand [236] or finger [93], subcutaneous tissue of the hypogastrium [93] and of the neck [237]. Other predilection sites are scrotum and testicles and, to a lesser extent, the breasts of women [1, 8, 65, 223, 235, 238–245]. Various reasons have been hypothesized for these preferences, such as lower body temperature of these areas, higher awareness of patients for these body parts or a tropism of D. repens to higher concentrations of sexual hormones [1].…”

“…The anamnesis should exclude the visit of the patient to endemic areas of other filarioids, such as Loa loa in Africa. In case of intraocular cysts or subcutaneous nodules, the diagnosis is more difficult, but a live moving worm can be seen using a pre-operative high-resolution ultrasound [231, 245].…”

Subcutaneous Lesion in an Oncologic Patient

“…Dirofilariasis mimicking breast cancer or a tumor of the scrotum also have been described. 4,5 In the differential diagnosis infestation with other Dirofilaria species must be ruled out. Dirofilaria immitis is endemic in Europe but is far less frequent.…”