TY  - CHAP
M1  - Book, Section
TI  - THYROID CANCER
A1  - Jameson, J. Larry
A1  - Weetman, Anthony P.
A2  - Longo, Dan L.
Y1  - 2013
N1  - 
T2  - Harrison's Hematology and Oncology, 2e
AB  - APPROACH  TO  THE  PATIENT:  A  Thyroid  NodulePalpable  thyroid  nodules  are  found  in  about  5%  of  adults,  but  the  prevalence  varies  considerably  worldwide.  Given  this  high  prevalence  rate,  practitioners  commonly  identify  thyroid  nodules.  The  main  goal  of  this  evaluation  is  to  identify,  in  a  cost-effective  manner,  the  small  subgroup  of  individuals  with  malignant  lesions.Nodules  are  more  common  in  iodine-deficient  areas,  in  women,  and  with  aging.  Most  palpable  nodules  are  >1  cm  in  diameter,  but  the  ability  to  feel  a  nodule  is  influenced  by  its  location  within  the  gland  (superficial  versus  deeply  embedded),  the  anatomy  of  the  patient's  neck,  and  the  experience  of  the  examiner.  More  sensitive  methods  of  detection,  such  as  computed  tomography  (CT),  thyroid  ultrasound,  and  pathologic  studies,  reveal  thyroid  nodules  in  >20%  of  glands.  The  presence  of  these  thyroid  incidentalomas  has  led  to  much  debate  about  how  to  detect  nodules  and  which  nodules  to  investigate  further.  Most  authorities  still  rely  on  physical  examination  to  detect  thyroid  nodules,  reserving  ultrasound  for  monitoring  nodule  size  or  as  an  aid  in  thyroid  biopsy.An  approach  to  the  evaluation  of  a  solitary  nodule  is  outlined  in  Fig.  48-1.  Most  patients  with  thyroid  nodules  have  normal  thyroid  function  tests.  Nonetheless,  thyroid  function  should  be  assessed  by  measuring  a  thyroid-stimulating  hormone  (TSH)  level,  which  may  be  suppressed  by  one  or  more  autonomously  functioning  nodules.  If  the  TSH  is  suppressed,  a  radionuclide  scan  is  indicated  to  determine  if  the  identified  nodule  is  "hot,"  as  lesions  with  increased  uptake  are  almost  never  malignant  and  fine-needle  aspiration  (FNA)  is  unnecessary.  Otherwise,  FNA  biopsy,  ideally  performed  with  ultrasound  guidance,  should  be  the  first  step  in  the  evaluation  of  a  thyroid  nodule.  FNA  has  good  sensitivity  and  specificity  when  performed  by  physicians  familiar  with  the  procedure  and  when  the  results  are  interpreted  by  experienced  cytopathologists.  The  technique  is  particularly  useful  for  detecting  papillary  thyroid  cancer  (PTC).  The  distinction  between  benign  and  malignant  follicular  lesions  is  often  not  possible  using  cytology  alone.In  several  large  studies,  FNA  biopsies  yielded  the  following  findings:  70%  benign,  10%  malignant  or  suspicious  for  malignancy,  and  20%  nondiagnostic  or  yielding  insufficient  material  for  diagnosis.  Characteristic  features  of  malignancy  mandate  surgery.  A  diagnosis  of  follicular  neoplasm  also  warrants  surgery,  as  benign  and  malignant  lesions  cannot  be  distinguished  based  on  cytopathology  or  frozen  section.  The  management  of  patients  with  benign  lesions  is  more  variable.  Many  authorities  advocate  TSH  suppression,  but  others  monitor  nodule  size  without  suppression.  With  either  approach,  thyroid  nodule  size  should  be  monitored,  ideally  using  ultrasound.  Repeat  FNA  is  indicated  if  a  nodule  enlarges,  and  a  second  biopsy  should  be  performed  within  2–5  years  to  confirm  the  benign  status  of  the  nodule.  
SN  - 
PB  - McGraw-Hill Education
CY  - New York, NY
Y2  - 2024/04/19
UR  - hemonc.mhmedical.com/content.aspx?aid=1128357924
ER  -