FIG 5. 2-year-old girl with a first episode of neck abscess. The pyriform sinus fistula was diagnosed at hypopharyngoscopy.

A, Contrast-enhanced CT scan shows an abscess (arrows) in the left thyroid and perithyroid tissue.

B, T2-weighted MR image (2000/90/2 [TR/TE/excitations]) shows a collection of high signal intensity (arrows) at the same region as in A.

C, Sonogram shows a hypoechoic mass (arrows) consistent with the abscess in the left perithyroid tissue, but the sinus tract is not visible.