Surgical findings
All patients, except one with congenital large goiter, underwent crystal
violet staining from the fistula opening in the PSF before resection.
The fistula cannot be detected during surgery in one of these stained
cases, while the fistula was resected completely under microscopic
surgery. No fistula cannot be distinguished as 3rd or
4th pouch origin by preoperative analyses. All
patients showed no recurrent nerve paralysis or recurrence. One patient
had wound infection, and another developed a keloid on the surgical scar
postoperatively.
Table 2 shows the surgical and histological features of all 12 cases.
Other 7 cases in this study cannot be used for analyses by various
reasons. We could track the pathological specimens. Four fistulas (Cases
1, 7, 11, and 12) started inside the thyroid cartilage, and most cases
were located behind the thyroid gland. Meanwhile, seven cases that
originated outside the thyroid cartilage penetrated the thyroid gland at
the superior pole. Therefore, we believe that there were two different
routes in PSF as shown in Figure 1: one passes inside the inferior horn
of the thyroid cartilage (Fig. 1a); another runs outside the horn (Fig.
1b).