<![CDATA[Mock26 MEN1]]>Stem
44-year-male patient seen in the clinic. History of mild asthma & parathyroid surgery, he had intermitted abdominal discomfort. Pancreatic disease is being considered.

Define parathyroid hyperplasia?

A non-malignant pathology in which there is proliferation and enlargement of parathyroid cells.

How many parathyroid glands usually affected?

All 4 glands

Microscopic picture of parathyroid hyperplasia?

Chief cell hyperplasia (most common pattern seen).
Less commonly, water-clear cell hyperplasia
In many circumstances, islands of oxyphils and delicate fibrous strands may envelop the nodules.

Define the 2 top reasons of parathyroid hyperplasia?

Renal failure
MEN syndrome

The patient collapsed in the clinic his glucose level can't be recorded immediately. Later confirmed to be 1.2 mmol/litre. History showed repeated attacks of sweating and fainting; what pancreatic neoplastic process may cause this clinical picture?

Insulinoma

Which part of the pancreas is usually affected?

Beta cells of islets of Langerhans.

How insulinoma is confirmed biochemically?

By finding high detectable insulin levels in blood stream at the same time hypoglycaemia is occurring.
High insulin-to-glucose ratio
High level of C-peptide

Apart from insulinoma what other pathology can create this condition?

Insulin like growth factors which produced from non-pancreatic tumours.
IGF-1
Hepatoma (serve liver disease)
Fibrosarcoma (retroperitoneal)
Insulin insensitivity

Define MEN?

Group of related conditions
Inherited as autosomal dominant
Characterized by hyperplasia or neoplasia of the endocrine organs.

What other pathology would you suspect in this patient?

Pituitary adenoma (MEN I)

What are the gene mutations that happens in insulinoma?

MEN1
Loss-of-function mutations in tumour suppressor genes such PTEN.
Inactivating mutations in two genes X-linked (ATRX) and death-domain associated protein (DAXX).

What is the two hit hypothesis?

Most loss-of-function mutations that occur in tumour suppressor genes are recessive in nature.
Thus, for a particular cell to become cancerous, both of the cell's tumour suppressor genes must be mutated.

What is telomere?

A region of repetitive nucleotide sequences at each end of a chromosome.
Which protects the end of the chromosome from deterioration or from fusion with neighbouring chromosomes.

What are the genes responsible for cancer in general?

Tumour suppressor genes
Proto-oncogenes
Micro-RNA genes
Mutatory genes: like BRCA 1 & 2

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