Let's go on to another case.
A 44 year old woman sees you in follow
up for evaluation of a thyroid nodule.
2 weeks ago, you palpated a 2 cm lateral
neck mass and a 2 cm left thyroid nodule.
She has a history of radiation therapy to the
chest at the age of 17 for Hodgkin's lymphoma,
but there is no family
history of thyroid cancer.
Ultrasound of the thyroid is positive for a
hypoechoic irregular margin thyroid nodule
with associated left cervical adenopathy.
What is the most likely
diagnosis in this patient?
There are unfortunately
some worrying signs here.
The 2cm lateral neck mass and the 2 cm left thyroid
nodule are seen in the setting of prior neck irradiation.
She also has a prior history of lymphoma.
Ultrasound findings identified are
hypoechoic nodule which means that it is dense.
With irregular margins and associated neck
adenopathy, these are very worrisome signs
that the nodule is more likely malignant.
The conclusion here is that the patient most
likely has papillary carcinoma of the thyroid
Radiation exposure at a young age
is a very strong risk factor
and fine needle aspiration of the
nodule and the associated lymph node
should be the next step in diagnosis.
Let's say a few words about thyroid cancer.
The incidence is rising faster
than any other type of malignancy
The incidence has more than doubled
in fact in the last 30 years.
This increase is due solely to the increase in
the numbers of identified papillary cancers.
With the highest rate of rise occuring
in tumors measuring less than 2 cm
Increased detection of otherwise occult
tumors is the most likely cause of this
given the increased rate of diagnostic imaging
that is performed around the world currently.
The survival rate for thyroid cancers has
remained stable or slightly improved with time.
Different types of thyroid cancers can be broken down
into those that present most commonly to least commonly.
Strating with the most common causes, papillary
thyroid cancer tends to affect the younger patients
and is associated with prior radiation
exposure particularly to the head and neck
The papillary-follicular variant is another
example of a fairly common thyroid cancer
and then a purely follicular variant which tends to occur
in older patients and rarely metastasizes to lymph nodes.
Less commonly are the medullary
carcinomas of the thyroid
also known as the parafollicular
1-2% of all thyroid tumors
will be medullary cancers.
When you pick up a medullary
cancer usually on pathology,
always screen that patient
for the RET protooncogene
because this may be associated with multiple
endocrine neoplasia (MET2A) type 2A.
Anaplastic thyroid cancers
are also quite rare,
the most aggressive form of thyroid cancer and they have
1 year survival rates that range between 20 and 30%
Even less commonly are thyroid lymphomas,
thyroid sarcomas or thyroid metastases.
Common causes of thyroid metastases include renal
carcinomas, breast cancers, melanomas and colon cancers.
Let's talk a little bit about medullary thyroid cancer.
It accounts for by far less than
10% of all thyroid cancers.
Approximately 25% of medulllary
thyroid cancers are hereditary
So always screen for the RET protooncogene
which will give you more information
about the genetics of the tumor.
It also may be associated with several syndromes
including multiple endocrine neoplasia.
MEN2A which may include pheochromocytoma
and MEN 2B which is usually discovered by
patients presenting with Marfanoid habitus,
mucosal ganglioneuromas, as well
as medullary thyroid cancer.
Familial medullary thyroid cancer can occur
independently without being part of MEN type syndrome
Biochemical screening for pheochromocytoma
with measurement of plasma
fractionated metanephrine levels
should be done in all patients in whom
RET mutations is found prior to them
undergoing surgery for thyroidectomy.
The treatment of thyroid carcinomas
usually requires surgery.
Some may also respond to
radioactive iodine ablation
Levothyroxine can be used to
suppress thyroid stimulating hormone
for patients with persistent
disease or high risk of recurrence.