Endocrine Surgery

Question 1

Dye used to identify parathyroid

Answer 1

Methylene blue

Question 2

In what condition if the serum calcium likely to be low

Answer 2

Secondary hyoerparathyroidism

Question 3

Monitoring for papillary thyroid cancer

Answer 3

Measurement of thyroglobulin levels

Question 4

Papillary thyroid cancer

Answer 4

Papillary carcinoma
• Commonest sub-type
• Accurately diagnosed on fine needle aspiration cytology
• Histologically they may demonstrate psammoma bodies (areas of calcification) and so called orphan Annie nuclei
• They typically metastasise via the lymphatics and thus laterally located apparently ectopic thyroid tissue is usually a metastasis from a well differentiated papillary carcinoma.

Question 5

Follicular thyroid cancer

Answer 5

Follicular carcinoma
• Are less common than papillary lesions
• Like papillary tumours they may present as a discrete nodule. Although they appear to be well encapsulated macroscopically there invasion on microscopic evaluation.
• Lymph node metastases are uncommon and these tumours tend to spread haematogenously. This translates into a higher mortality rate.
• Follicular lesions identified at FNAC are allocated either a THY 3a (atypical cells) or
THY 3f (follicular lesion) the latter group should undergo a hemithyroidectomy and the former a repeat FNAC

Question 6

Anaplastic thyroid cancer

Answer 6

Anaplastic carcinoma
• Less common and tend to occur in elderly females
• Disease is usually advanced at presentation and often only palliative decompressic and radiotherapy can be offered.

Question 7

Medullary thyroid cancer

Answer 7

Medullary carcinoma
• These are tumours of the parafollicular cells ( C Cells) and are of neural crest origin.
• The serum calcitonin may be elevated which is of use when monitoring for recurrence.
• They may be familial and occur as part of the MEN -2A disease spectrum.
• Spread may be either lymphatic or Haematogenous and as these tumours are not derived primarily from thyroid cells they are not responsive to radioiodine.

Question 8

Which thyroid condition is associated with lithium use

Answer 8

Hypothyroidism

Lithium induced hypothyroidism and goiter may take weeks to years after it is started.
Studies have shown that the prevalence rates of lithium-induced hypothyroidism range from 3.4% to 52%, with a female-to-male ratio of approximately 5:1. The clinical presentation of hypothyroidism is similar to that of the patient’s not on lithium and the biochemical changes are identical to those in primary hypothyroidism. Hyperthyroidism can result but is less common. Routine monitoring of thyroid function should occur in all patients taking lithium.

Question 9

Where are thyroglossal cysts most commonly located

Answer 9

Immediately below the hyoid bone

Question 10

Pre-op meds for phaeochromocytoma

Answer 10

Phenoxybenzamine

a Blockers are the safest drugs to control the hypertension. The use of b blockers is dangerous and should be avoided.

Question 11

Chemotherapy used for adrenocortical adenocarcinoma

Answer 11

Mitotane is the first line treatment for advanced disease and offers reasonable palliation.
Chemotherapy with cisplatin and rarely radiotherapy may be considered.

Question 12

What antibody is used to identify Graves’ disease

Answer 12

TSH receptor antibodies (95%)

Antithyroid peroxidase and anti thyroglobulin are seen in a smaller percentage of cases.

Question 13

Treatment for papillary thyroid cancer

Answer 13

Hemithyroidectomy can be considered the complete treatment for papillary cancers which are:
- <1 cm
-Unifocal
-No family history
- No radiation exposure

Node dissection of level VI nodes is sensible in high risk patients

Question 14

Presence of Hurthle cells on histology

Answer 14

Hurtle cell lesions are a subtype of follicular thyroid cancer and considered to have an adverse prognosis. Almost all cases should be considered for total thyroidectomy and some surgeons would also undertake central nodal dissection.

Question 15

Glucagonoma

Answer 15

90% of glucagonomas are malignant
70% will have necrolytic migratory erythema

Question 16

Incidence of Recurrent laryngeal nerve injury

Answer 16

1.8% at 1 month which declines to 0.5% at 3 months

Question 17

Parathyroid cancer

Answer 17

• Rare condition
• Equal gender ratio
• Marked hypercalcaemia, neck mass may be present and lesion usually larger than simple adenomas
• If suspected then en bloc resection of the affected half of the thyroid and adjacent soft tissues is performed
• Survival rates with en bloc, RO resection = 89% overall (5 years)
• Simple parathyroidectomy = 53% survival rate

When parathyroid cancer is suspected a radical excision is indicated without pre-operative tissue sampling. FNA assessments of these lesions are unreliable and core biopsy risks seeding the tumour through the strap muscles and may compromise cure. Histological criteria favouring malignancy include capsular invasion, mitoses and rosette like cellular architecture.

Question 18

MIBG scan

Answer 18

Meta-iodobenzylguanidine scintiscans (MIBG) scans are indicated in the work up of suspected adrenal phaeochromocytoma for the detection of extra adrenal disease.

Question 19

Presenting features of cushings

Answer 19

Presenting features:
Obesity 95%
Hirsuitism 80%
Hypertension 80%
Myopathy 60%
Buffalo hump 55%
Easy bruising 40%

Question 20

Clear cells found on biopsy

Answer 20

Renal cell carcinoma are the tumour type most likely to metastasise to the thyroid. These will often have a clear cell morphology histologically. Clear cell sarcomas are very rare and thyroidal metastasis from them rarer still.

Question 21

Adrenal mass follow up

Answer 21

Follow up Ct scan at 6, 12 and 24months for benign (<4cm tend low incidence)

3-6months if concerns

Question 22

Risk of hypocalcaemia in thyroidectomy

Answer 22

5% - in 80% of these cases the situation resolved over the following 12 months

Question 23

Which cancer is associated with non-therapeutic irradiation of the neck

Answer 23

Exposure to ionising radiation particularly in the young can predispose to thyroid cancer and 85% of these tumours are papillary. Papillary cancers that occur following radiation exposure should generally be treated by total thyroidectomy even if small.

Question 24

Hashimotos thyroiditis antibodies

Answer 24

Antibodies to thyroid peroxidase are found in most patients with Graves disease or
Hashimotos thyroiditis.

Question 25

USS features of malignancy

Answer 25

USS features of malignancy
• Hypochoity
• Microcalcifications
• Lymphadenopathy
• Loss of halo
• Irregular margins

Question 26

PTH actions to increase serum calcium

Answer 26

PTH increases the activity of 1-a-hydroxylase enzyme, which converts 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol, the active form of vitamin D.
Osteoclasts do not have a PTH receptor and effects are mediated via osteoblasts.

Question 27

Measurement of thyroglobulin levels are most likely useful in which cancer

Answer 27

Thyroglobulin is synthesized by the follicular cells of the thyroid and levels are more likely to be elevated in well differentiated follicular thyroid cancers in which it can be used to screen for recurrence.