L36 Endocrine pathology - Pituitary and Thyroid Flashcards
There is overlapping features of adenoma and carcinoma
such as pleomorphism, capsular/vascular invasion.
meaning that histology is not useful
(except in?)
What serves as the most accurate diagnostic criteria?
Except in
- Papillary thyroid carcinoma
- Neuroblastoma
Metastasis as the most accurate diagnostic criteria
Causes for hyperpituitarism? (5)
Which cause is the most common?
- Adenoma (MC)
- Hyperplasia
- Carcinoma
- Ectopic production e.g. SCLC
- Hypothalamic diseases
What are the causes for hypopituitarism? (4)
MC for adult and child?
- Non-functioning adenoma (MC in adult): mass effect
- Rathke cleft cyst (MC in child) :from Rathke’s pouch (embryonic remnant of anterior pituitary)
- Ischemic injury: Sheehan syndrome (postpartum necrosis of anterior pituitary)
- Inflammation (e.g. TB), irradiation (chemotherapy of NPC)
List possible consequences of mass effect of the pituitary gland. Briefly explain too. (5)
- Hypopituitarism: loss of all normal pituitary cell types/ isolated excess in hormone from tumor
- Bitemporal hemianopia: compression on optic chaism
- Ophthalmoplegia: compression of CN3,4,6
- Headache: stretching of diaphragm sella, raised ICP (due to obstruction to CSF drainage)
- Pituitary apoplexy: sudden onset of neurological dysfunction due to bleeding into or impaired blood supply of pituitary gland at the base of the brain
(apoplexy = bleeding in internal organs with symptoms)
What do you expect to see on X-ray when there is a mass effect caused by pituitary gland?
Sellar expansion, bony erosion.
Name the types of pituitary adenomas. (3)
- Functioning = with multuple/single trophic hormones
- Non-functioning
- Prolactinoma (MC)
- Gonadotroph adenoma
- Null cell adenoma: non-functioning (2nd MC)
What are macroadenoma and microadenoma?
Macroadenoma >1cm
Microadenoma <1cm
- confirmed to sella, thus producing no mass effect-induced symptoms
Pituitary adenomas
A. They are invasive to adjacent bones, dura and brain
B. They are not metastatic
C. They may have hemorrhagic foci
D. There is clonal expansion of primitive stem cell usually in the anterior pituitary, thus monoclonal in origin
E. Reticulin stain is used to distinguish adenoma (+ve) from normal gland (-ve)
All except E!
E: Reticulin stain is used to distinguish adenoma (-ve) from normal gland (+ve)
B: thus they are different from carcinoma
Other than reticulin stain, what can be used to investigate pituitary adenomas?
IHC for anterior pituitary hormones
- IHC +ve for a particular hormone in adenoma does not mean that tumor is actively secreting that normal
- therefore functional aspect of the pituitary adenoma cannot be assessed by histopathology
Thyroid gland disorder are classified by morphology (diffuse, multiple nodular, diffuse) and thyroid status.
List Ddx for hyperthyroidism. (7)
- Grave’s disease
- Toxic multinodular goitre (Plummer’s disease)
- Toxic adenoma
- De Quervain thyroiditis (subacute, viral infection like mumps)
- Subacute lymphocytic thyroiditis
- Struma ovarri (teratoma)
- Factitious thyrotoxicosis (overdose)
List Ddx for hypothyroidism? (3)
- Cretinism in neonates (severely impaired physical and mental development) or myxoedema in adults
- Hashimoto’s thyroiditis
- Iodine deficiency
A patient has a neck lump that is diffuse and non-toxic.
What is the possible diagnosis?
Simple goitre/colloid goitre/ diffuse goitre
Simple goitre/colloid goitre/ diffuse goitre contains enlarged follicles with ?
Colloid
A nodular goitre can be solitary or multiple. The patient can appear to be euthyroid or hyperthyroid (if toxic multi nodular).
Regressive changes such as calcification, fibrosis and hemorrhage can be picked up by?
USG
Cause of Grave’s disease?
Clinical manifestations?
Strongly associated with what MHC class II cell surface receptor?
Autoimmune cause
Clinical manifestations - Triad
- Diffuse thyrotoxic goitre
- Infiltrative ophthalmology (thyroid eye signs)
- Infiltrative dermopathy (pretibial myxoedema)
associate with HLA-DR3
What is the pathogenesis of Grave’s disease?
- TSI (thyroid stimulating immunoglobulin) stimuates TSH receptor
- Thyroid stimulating antibodies mimics TSH to stimulate oversecretion of thyroid hormone
- other autoantibodies targeting
2. TPO (thyroid peroxidase)
- Thyroglobin
What would you expect to see histologically in Grave’s disease?
What would you expect to see in extraocular muscles in Grave’s disease?
Diffuse hyperplasia of follicular epithelium with T-cell infiltration
- bland-looking thyroid follicles
Extraocular muscles
-Lymphocytic infiltrates, muscular destruction
Cause of Hashimoto’s thyroiditis?
Clinical manifestations?
Autoimmune
(usually associated with other autoimmune diseases)
Initial thyrotoxicosis - Hashitoxicosis due to gland destruction (transient thyrotoxicosis)
Null cell adenoma
A. Is chromophobic
B. no PAS positivity
C. No lead hemtoxylin positibity
D. no carmoisine positivity
E. Electron microscopy can reveal their morphogenesis
F. 2nd MC non-functioning pituitary adenoma
All except E
- cannot
chromophobic = resist to staining with dyes