A case of perithyroidal actinomycosis in a child with pyriform sinus fistula

(A) Computed tomography showing an ill-defined lesion with inner central necrosis and rim enhancement in the left perithyroidal area. (B) Follow-up computed tomography showing marked increase of the ill-defined soft tissue mass with abscess formation. (C) Postoperative computed tomography showing marked improvement after incision and drainage.

(A) Hypopharyngoscopy revealing the opening at the left pyriform sinus apex (arrowhead). (B) Barium swallow showing an irregular tract extending from the left pyriform sinus (arrowhead).

Histologic photography showing a typical sulfur granule (hematoxylin–eosin stain, original magnification 100×).