Download Benign Follicular Adenoma

Benign
Follicular
Adenoma
Benign neoplasms derived from follicular epithelium
solitary spherical lesion compressing
on non-neoplstic thyroid
well-demarcated by well-formed capsule
contains colloid
often discovered on
routine examination
large masses may cause
difficulty in swallowing
cells
arranged in
well-formed
follicles
Painless
nodule
cells are uniform with
well-defined cell
borders
variant of
follicular
adenoma
thyrotoxicosis
"hot" nodules on
radionuclide scanning
malignancy
almost non-existent
in
"hot"nodules
takes up
more iodine
than normal
tissue
"Cold" nodules on
radionuclide scanning
but 10% of cold
nodules eventually
prove to be malignant
Toxic
adenoma
Morphology
Hurtle
cell
Adenomas
take up less
iodine than
normal tissue
Clinical
Features
however, distinction b/w
follicular adenoma & follicular
carcinoma can only be made
pathologically after resection
cells acquire
brightly
eosinophilic &
granular
cytoplasm
sign of
metaplastic
change
Histology
Does
not
undergo
malignant
change
similar
clinically
to
follicular
adenoma
Careful
evaluation of
capsule is
critical
rarely has
papillary
change
presence of capsular
or blood vessel
invasion is diagnostic
of follicular carcinoma
papillary change should
suggest suspicion of
encapsulated papillary
carcinoma
rare variety of
benign
adenoma that
produce thyroid
hormone
autonomously
Toxic
Adenoma
cells
contain
mutations
of TSH
receptor
genes
hormone
production
independent of
TSH
stimulation
causes
clinical
thyrotoxicosis
cause
receptors to
be
persistently
turned on
continuous thyroid
hormone
production &
hyperthyroidism
even in absence
of TSH