Human Dirofilaria repens infection of the zygomatico-temporal region

A 40-year old patient developed a painless swelling in the left zygomatico-temporal region. Magnetic resonance images and computed tomograms showed a non-specific soft tissue mass in the tumour region, but no invasion of bone. After application of antibiotics, the tumour reduced in size but a firm mass of about 3 cm in maximum diameter persisted under therapy. Surgical exploration revealed a distinct firm mass adhering to the superficial layer of the temporal muscle. Histological and molecular biological investigations demonstrated fragments of Dirofilaria repens in the centre of the lesion. Clinical follow-up was uneventful and additional investigations excluded further manifestations of the parasite. D. repens infections are extremely rare in northern Europe, but recent reports about the increase of human dirofilariasis in northern parts of Europe should alert the clinician to include helminthoses in the differential diagnosis of atypical space-occupying lesions of the maxillofacial regions.