A Case of Pyriform Sinus Fistula Infection with Double Tracts

Figure 3

Pathological findings by hematoxylin and eosin staining of the brownish tract ((a)–(d)) and the crystal violet-stained tract ((e), (f)) and a view of the ends of the tracts ((b), (f)). (a) Epithelium of the lumen was completely replaced by granulation tissue and inflammatory cells. (b) The end of the brownish tract has invaded the thyroid beyond the capsule. (c) The brownish tract contained a foreign substance (arrow) that was surrounded by multinucleated giant cell (arrowhead). (d) Another foreign substance was seen in the granulation tissue of the brownish tract. These substances are observed everywhere, which proved the previous communication with the pharyngeal lumen. (e) An internal lumen (asterisk) covered by epithelium has obviously formed. (f) The terminus is a blind end (arrow) that does not enter the thyroid across the capsule.

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