RT Book, Section
A1 Suliburk, James
A1 Delbridge, Leigh
A2 Morita, Shane Y.
A2 Dackiw, Alan P. B.
A2 Zeiger, Martha A.
SR Print(0)
ID 6162002
T1 Chapter 1. Thyroid Nodule
T2 McGraw-Hill Manual: Endocrine Surgery
YR 2010
FD 2010
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-160645-5
LK accesssurgery.mhmedical.com/content.aspx?aid=6162002
RD 2024/04/19
AB To  treat  thyroid  disease,  it  is  essential  to  have  a  thorough  knowledge  of  its  embryology.  The  thyroid  is  derived  from  the  primitive  pharynx  as  well  as  the  neural  crest  with  the  main  body  arising  from  epithelial  cells  of  the  endoderm  and  forming  the  follicles  of  the  gland.  Arising  as  a  diverticulum  from  the  floor  of  the  primitive  pharynx,  the  thyroid  transforms  into  a  bilobed  structure  and  descends  in  the  midline  of  the  neck.  This  tract  remains  attached  to  the  posterior  inferior  tongue  as  the  thyroglossal  duct,  and  its  distal  end  may  go  on  to  form  a  pyramidal  lobe.  This  serves  as  the  embryologic  basis  for  the  formation  of  a  thyroglossal  duct  cyst  as  well  as  nodules  within  the  pyramidal  lobe,  and  underscores  the  need  to  completely  excise  the  thyroglossal  tract  through  the  hyoid  bone  to  the  level  of  the  foramen  cecum  when  the  aforementioned  cyst  is  present.  It  also  requires  the  surgeon  to  systematically  search  for  a  pyramidal  lobe  when  performing  a  total  thyroidectomy  because  it  is  present  in  30%  to  40%  of  patients  and  will  be  the  point  of  persistent  or  recurrent  disease  if  not  identified  at  the  time  of  operation.1