Figure 1
Tiger mosquito. (A) Its appearance. (B) Illustration of its distribution in France in recent years, from 2006 to 2025, showing its almost exponential expansion from south to north.
Figure 2
Picture of a Dirofilaria repens worm under operative microscope magnification. The image shows a surface with coarse longitudinal ridges (arrows) and numerous transverse annular strictures (arrowheads).
Figure 3
Histology of a Dirofilaria repens. Several sections of the worm show the peripheral cuticle covering a muscular layer. The central cavity contains the worm’s digestive tract and two genital tubes. The worm is located in a cystic cavity containing various inflammatory elements (Courtesy of C. Godfraind).
Figure 4
Temporal region examinations previously performed at other institutions. (A) T1‑weighted MRI, performed after intravenous administration of contrast agent, shows a small hypodermal formation with a high signal corresponding to vascularized tissue (arrow). (B) to (D) Ultrasounds respectively performed 1 month, 14 months, and 18 months later all show the overall hypoechoic appearance of the lesions, containing curious fine echogenic structures in the shape of a ‘rail’ (arrows).
Figure 5
New MRI performed at our institution. The lenticular formation located in the deep hypodermal plane of the temporal region (arrows) shows a low to intermediate signal on T1‑weighted image (A), with signal enhancement after contrast injection (B), and a high signal on T2‑weighted images with fat saturation (C). Note the heterogeneity of the central portion of the mass, which contains small unenhanced areas (black arrowhead in B).
Figure 6
A new ultrasound scan performed immediately after the new MRI. (A) Conventional images perpendicular to the skin surface show a poorly defined, heterogeneous, hypoechoic deep hypodermal mass containing rectilinear double echogenic structures several millimeters long (arrows) or very short, almost point‑like (arrowheads). (B) Color Doppler examination shows clear hypervascularization. (C) A nearly ‘horizontal’ slice, close to a plane parallel to the skin, taken after more than 10 minutes of examination, shows that the double echogenic structure has curved portions (arrows). It is at this stage that spontaneous movements of the structure were observed (see Figure 7).
Figure 7
Images extracted from a short ultrasound video taken late with the motionless probe almost tangent to the skin plane, show that certain echogenic structures move and then disappear (arrowheads in A, B, and C), resulting from their spontaneous mobility.
Figure 8
Photographs taken from a video of the open surgical excision specimen. A whitish, threadlike structure corresponding to the worm emerges from the tissue mass through a breach. Some portions of the worm are mobile (arrows in A, B, and C and arrowheads in C and D).