What is a thyroid gland ?  The   thyroid   gland   is   a   small   organ   in   the   midline   of   the   neck,   just   below   the   Adam's   apple (larynx). It is easy to recognize a thyroid swelling- it moves up on swallowing ! The   function   of   the   thyroid   gland   is   to   make   a   hormone   called   'thyroxine'. A   normal   amount of   thyroxine   is   required   for   normal   physical   and   mental   development.   In   adults,   thyroxine keeps cells and tissues working at just the right metabolic rate. What can go wrong with it ? However,   lumps   or   masses   can   arise   in   the   thyroid   causing   different   thyroid   diseases.   A visible   enlargement   of   the   thyroid   gland   is   called   Goitre.   The   entire   gland   may   be   involved or   there   may   be   single   or   multiple   nodules   or   lumps.   Thyroid   masses   can   also   be   associated   with hormonal   imbalance.   Patients   with   overactive   or   under-active   thyroid   glands   can   have   goitre   but most goitres produce a normal amount of thyroxine. An    overactive    thyroid    gland    would    produce    too    much    thyroxine    causing    hyperthyroidism    The symptoms   of   this   condition   include   tremor,   heat   intolerance,   irritability,   increased   energy,   poor sleep, weight loss and frequently, bulging eyes. Patients generally have a high metabolic rate. Too   little   thyroxine   from   an   under-active   gland   causes   an   illness   with   a   low   metabolic   rate   called hypothyroidism. This   condition   causes   tiredness,   weight   gain,   swelling   and   slowness   of   speech   and thinking. Single Nodule A   single   swelling   or   lump   (nodule)   in   the   thyroid   gland   is   a   special   form   of   goitre.   The   majority (90%)   of   the   nodules   are   not   cancerous   but   either   simple   swellings   of   fluid   (cysts)   or   benign growths of thyroid tissue with no tendency to spread or invade structures. The   remaining   10%   are   usually   a   very   low-grade   form   of   cancer,   which   is   almost   always   completely curable.   There   are   a   very   small   number   of   nodules   that   turn   out   to   be   a   more   aggressive   form   of thyroid cancer, these occur in special situations and are very rare. Multinodular Goitre (MNG) Frequently   the   lumps   are   not   single   but   multiple   and   part   of   an   innocent,   non-cancerous   condition   called   MNG,   which   just   means   that   several swellings are present. Occasionally they can be later found to harbour cancer cells ! Cyst Cysts   (fluid   collections)   in   the   thyroid   are   common.   Frequently   they   are   present   without   the   patient   noticing   but   sometimes   they   can   enlarge so that they can be felt. Colloid Nodules These are benign nodules made up of thyroid tissue that have become enlarged. They can be single or multiple and can sometimes become very large. Surgery becomes necessary if the nodule becomes large and causes compressive symptoms or if they cause cosmetic deformity. Non-Cancerous Tumours These   tumours   (generally   'adenoma')   are   caused   by   an   abnormal   growth   of   thyroid   follicle   cells. They   have   no   capacity   to   spread   or   cause   destruction   of   tissue   but   they   cannot   be   differentiated   from one    of    the    types    of    thyroid    cancer    on    FNAC    (please    see    next    column).    Surgery    is    usually recommended for diagnosis. Thyroid Cancers The   most   common   thyroid   cancers   are   differentiated   thyroid   cancers   named   either   papillary   or follicular        cancer. T  h  e  s  e    make   up   more   than   90%   of   thyroid   cancer   and   they   very   rarely   cause   death.   They   do   have   the potential     to     spread     to     lymph nodes   in   the   neck   and   to   other   parts   of   the   body   such   as   the   lungs   but   even   if   they   do,   these   tumours are    still    treatable.    Surgery    is necessary in most cases. So what are the complications? Goitres,   especially   MNG,   can   become   very   large   and   cause   pressure   on   the   windpipe   (trachea)   and swallowing    tube    (oesophagus). This   can   result   in   shortness   of   breath,   voice   change,   cough,   increased   pressure   sensation   in   the neck and sometimes difficulty swallowing. Surgery   to   remove   the   thyroid   gland   is   usually   necessary   to   treat   large   goitres   that   are   causing symptoms.   Surgery   is   also   necessary   where   there   is   a   suspicion   of   thyroid   cancer   in   an   enlarged thyroid gland and where the swelling is causing cosmetic deformity. So, how is a thyroid problem diagnosed? 1.   An   ultrasound   scan   may   be   requested   to   measure   the   shape   of   the   thyroid   and   to   look   for nodules or cysts within the gland. 2.   Fine   needle   aspiration   cytology   (FNAC) .   This   is   an   extremely   valuable   test   for   diagnosing thyroid   lumps. A   small   sample   of   cells   or   fluid   is   removed   from   the   thyroid   gland   by   passing   a   needle through   the   nodule   or   cyst   in   the   gland. The   aspirate   is   then   examined   under   the   microscope   and   the type   of   cells   making   up   the   swelling   can   be   seen.   The   test   is   usually   80-90   percent   accurate. Histology    (Study    of    the    cells    making    up    the    sweling)    of    the    mass    in    question    is    important    to differentiate   a   cancerous   and   non-cancerous   type,   and   further   to   that,   which      particular   subtype   of cells. This in turns makes a big difference in the subsequent treatment of the mass.

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This patient education is provided in good faith to help patients and their families learn more about their medical conditions, the options available to them and the possible consequences of their decisions. This information is not intended to be used for diagnosis, or treatment of any specific individual. Please consult with your ENT doctor regarding your particular circumstances.

Last update:  10/1/13 

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Alternatively, FNAC can be more accurately performed under ultrasound guidance, called ultrasound-guided FNAC. It is more superior for deep-seated masses as the ultrasound allow a real-time precise targeting of the needle into the lesion in question (analogy is a soldier wearing a night-vision infra-red goggle in pitch-black darkness shooting at a target !) Other than thyroids, this technique can also be applied to other head and neck masses, as in here. The advantages of ultrasonography is that it is rapid, inexpensive, versatile, no ionizing radiation (eg. CT scan, X ray) is applied, does not require injection of contrast medium and can be easily repeated when necessary Ultrasound guided fine needle aspiration cytology (FNAC) is a safe diagnostic procedure in which any structure visualized can be reached quickly and precisely by a fine needle in any desired plane with constant visualization of the needle tip during insertion. 3.   Endoscopic   examination   of   the   vocal   cords    to   exclude   potential   involvement   of   the   nerve   (recurrent   laryngeal   nerve   RLN)   supplying   the vocal cords pre- and post-surgery. This can be done in the outpatient clinic after applying some local anaesthetic nasal spray. As   a   thyroid   cancer   may   infiltrate   into   the   nerve   supplying   the   vocal   cord   muscles,   similarly   the   thyroid   surgery   itself   may   potentially   affect   the function   of   the   nerve,   it   is   vital   to   know   the   status   of   the   voice   box   (vocal   cords)   before   and   after   the   surgery.   Any   vocal   cord   weakness   can affect the voice and swallowing function. .

4.   CT   scan    may   be   necessary   if   there   is   recurrent   goitre,   thyroid   cancer   with   involved   lymph   nodes   or   a   large   retrosternal   (a   thyroid gland that grows into the chest cavity) thyroid causing compression. CT is not usually indicated for smaller palpable thyroid lumps. 5. Blood tests looking for the function of the gland (free T4, TSH), thyroid antibody levels, thyroglobulin levels may be needed. The   final   management   of   the   patient,   surgical   or   non-surgical,   would   very   much   depend   on   the   symptoms   and   the   results   of   the investigations. Surgery may be needed in symptomatic or large thyroid swellings and if cancer is suspected.

An ultrasound of the neck in progress, with the red arrow showing the probe

An ultrasound image of a thyroid mass (the blue line showing the approximate size)

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Head & Neck Swellings

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An ultrasound of the thyroid in progress using color Doppler scan