Session 11

Question 1

Where is the pituitary gland?

Answer 1

slide 4 lec 1

Question 2

Why is the pituitary gland a “two in one gland”?

Answer 2

• a.k.a. hypophysis or hypophysis cerebri • Closely related to the hypothalamus • Two lobes • Posterior • neuroendocrine • Anterior • endocrine
• The pituitary has ectoderm AND neurectoderm origins
• Rathke’s pouch • Ectoderm • Anterior pituitary • Infundibulum • Neurectoderm • Posterior pituitary
slide 5 lec 1

Question 3

Infundibulum

Answer 3

• Neural tube component • Downward out-growth of the forebrain
• grows towards the roof of the pharynx

Question 4

Rathke’s pouch

Answer 4

• Out-pocketing of ectoderm of the stomatodeum • An evagination of the roof of the (oro-) pharynx • Grows dorsally towards the developing forebrain

Question 5

Derivation of the pituitary gland

Answer 5

Rathke’s puch - anterior pituitary

infundibulum - pituitary stalk and posterior pituitary

Question 6

Describe location of tongue, and whats its made of?

Answer 6

• Lies partly in the oral cavity 
& partly in the pharynx
• Highly mobile
• Lingual frenulum
• Comprised of intrinsic & 
extrinsic muscles

Question 7

Describe the development of the tongue

Answer 7

• Primordia of the tongue appear at about the same time as the palate begins to form • Receives a component from each of the Pharyngeal arches
• 2 lateral lingual swellings • Ph Arch 1 • 3 median lingual swellings • Ph Arch 1 • Tuberculum impar • Ph Arch 2 & 3 (+4) • Cupola • Ph Arch 4 • Epiglottal swelling
• Lateral lingual swellings over-grow the tuberculum impar • The 3rd arch component of the cupola over-grows the 2nd arch component • Extensive degeneration occurs, freeing tongue from the floor of the oral cavity • lingual frenulum

Question 8

Describe the sensory innervation of the tongue and how it relates to its development

Answer 8

• Mucosa of anterior 2/3s derived from Ph As 1 & 3 • General sensory innervation CN V & IX • Posterior 1/3 derived from Ph A 3 (& 4) • General & special sensory CN IX & X • taste buds develop in papillae • Special sensory innervation CN VII

Question 9

Chorda tympani and the tongue

Answer 9

• branch of CN VII, nerve of second arch • BUT • passes into first arch • THEREFORE • passes through middle ear

Question 10

Motor innervation of the tongue in relation to its development

Answer 10

• Both intrinsic & extrinsic muscles of the tongue develop from myogenic precursors that MIGRATE into the developing tongue •CN XII

Question 11

The thyroid gland and its development

Answer 11

• Primordium of the thyroid gland appears in the floor of the pharynx between the tuberculum impar and the cupola • Final position is anterior neck
Descent of the thyroid • Point of origin for the descent of the thyroid is later marked by foramen cecum • Bifurcates and descends as a bi-lobed diverticulum connected by the isthmus

Question 12

Thyroglossal duct

Answer 12

• During its descent the thyroid gland remains connected to the tongue by the thyroglossal duct • Pyramidal lobe • Approx 50% of population

Question 13

Thyroid abnormalities from development

Answer 13

• Thyroglossal cysts & fistulae • Ectopic thyroid tissue

Question 14

Summary I: the midline structures development

Answer 14

• Pituitary • Ectoderm (Rathke’s pouch) + neurectoderm (infundibulum) • Tongue • Forms in the floor of the pharynx with contributions from all 5 Ph Arches • Thyroid • Midline diverticulum in floor of pharynx • Migrates anterior to pharyngeal gut, hyoid bone & laryngeal cartilages

Question 15

What embryonic structures contribute to the development of the face?

Answer 15

panopto

Question 16

What structures in the developing face must fuse to form the upper lip and jaw

Answer 16

pano

Question 17

Cleft lip & palate

Answer 17

• Palate is formed from palatal shelves which grow medially into oral cavity from the maxillary prominence • Once mandible has enlarged sufficiently to allow the tongue to “drop” the palatal shelves meet in the midline and fuse • Cleft lip & palate results from failure of FNP to fuse with Max P and failure of palatal shelves to fuse

Question 18

The importance of neural crest

Answer 18

• First arch syndrome • spectrum of defects in development of the eyes, ears, mandible & palate • Thought to result from failure of colonisation of the 1st arch with neural crest cells • Example – Treacher Collins Syndrome
• Each arch has an associated cranial nerve, artery and cartilage bar • 4 CNs innervate the derivatives of the pharyngeal arches • CN V, CN VII, CN IX & CNX • CN XI & CN XII • Cartilage bars are remodelled to form skeletal structures of the H & N

Question 19

Treacher-Collins syndrome

Answer 19

• Characterised by hypoplasia of mandible & facial bones • Inherited, autosomal dominant condition • Haploinsufficiency of Treacle, a serine/alanine rich nucleolar phosphoprotein. It is involved in ribosomal DNA gene transcription as well as in processing of the pre-ribosomal RNA. Deficiency of treacle leads to insufficient ribosome biogenesis, and impacts on NC migration

Question 20

Di-George syndrome

Answer 20

• Congenital thymic aplasia & absence of parathyroid glands • Syndrome including a variety of additional defects • “CATCH22” • Deletion on Chromosome 22 • Disruption of development of 3rd and 4th pharyngeal pouches • Abnormal development of neural crest

Question 21

CHARGE Syndrome

Answer 21

• CHD7 (chromodomain helicase DNAbinding domain, ATP-dependant chromatin remodeller) • CHARGE syndrome • CHD7 heterozygous mutation • CHD7 expression essential for the production of multipotent NC
C – coloboma H – heart defects A – choanal atresia R – growth & developmental retardation G – genital hypoplasia E – ear defects

Question 22

Thyroid blood supply

Answer 22

superior thyroid artery and inferior thyroid artery. Drains via superior thyroid veins and middle thyroid veins into internal jugular veins and inferior thyroid veins into left and right brachiocephalic veins

Question 23

Anatomy of RLN and LRN

Answer 23

panopto

Question 24

How to find RLN

Answer 24

(Beahears triangle) check learning objectives

Question 25

Risk factors for head and neck cancer

Answer 25

• Smoking • Alcohol • Betal nut chewing (oral ca) • Dental hygiene (oral ca) • Viruses- HPV for oropharynx • Premalignant

Question 26

Specific risk factors for thyroid cancer?

Answer 26

* Irradiation exposure (including radioactive iodine & radiation leaks) • Family history and certain inherited conditions (e.g. FAP) * Young lumps or old lumps (<20 or >70yr olds) in thyroid glands are more likely to be malignant

Question 27

Premalignant conditions making you at risk to cancer

Answer 27

– leucoplakia – Erythroplakia slide 16 lec 2

Question 28

Staging H&N Cancers

Answer 28

• Tumour – Specific to each tumour (typically 1-4, the larger the number the larger the tumour and worse prognosis • Nodes (cervical) – The nodal status is almost uniform for all H&N cancers • Metastasis – The presence of distant spread (incurable)

Question 29

General principles of new cancer management

Answer 29

* Assessment: – Patients fitness for intervention – Clinical staging – Radiological staging * Biopsy: – To have a tissue diagnosis * Discuss @ MDT (involve all who may help): – Curative or palliative intention? * Definitive management with patient involvement * Supportive – Swallowing – Feeding (assisted feeding) – Voice rehab – Pain – Supportive care MDT Approach with: – Oncologist – Surgeons – Radiologists – Pathologists – Cancer support nurse – SALT – Dieticians * Medical (oncology) – Radiotherapy (RT) – Chemothearphy (<70) * Surgical – Assessment of the tumour – Sample (biopsy) – Remove (if possible) – Reconstruct

Question 30

Lip/oral cavity cancer (presentation, investigations, treatment)

Answer 30

• Presentation – Lump – Pain (included referred pain to the ear) – Fixation of tongue – Problems swallowing (dysphagia) – Pain on swallowing (odynophagia) • Investigations – Biopsy – May need imaging with a CT +/- MRI (include chest)- not needed for superficial lip lesions – May need PET • Treatment – Small tumours excise and repair the defect – Radiotherapy (bad morbidity) – Larger tumours that do not respond to RT may need extensive surgery (hemiglossectomy or total glossectomy)

Question 31

Pharynx cancer (presentation, investigations, treatment)

Answer 31

* Presentation – Lump (mainly nodal mets or unknown 1o) – Pain (included referred pain otalgia) – Problems swallowing (dysphagia) – Pain on swallowing (odynophagia) – Weight loss Often present late (25% are untreatable at presentation) * Investigations – imaging with a CT +/MRI (include chest) – May need PET – Biopsy * Often need feeding assistance with gastrostomy tubes * Treatment – Small tumours excise and repair the defect – Radiotherapy – Larger tumours that do not respond to RT may need extensive surgery (mandibular split or other type of pharyngectomy or robotic procedure)

Question 32

Larynx cancer (presentation, investigation, treatment)

Answer 32

* Presentation – Dyphonia (voice change)- main feature – Dyphagia – Referred otalgia – Glogus – Neck lump – Weight loss – Cacexia * Investigations – imaging with a CT (include chest) – May need PET – Biopsy * Often have long term voice issues and/or swallowing problems • Treatment – Small tumours may have resection or RT – Medium size tumours do well with RT +/chemo – Larger tumours that do not respond to RT may need extensive surgery (laryngectomy)

Question 33

Thyroid cancer (presentation, investigation, treatment)

Answer 33

• They either tend to present with a lump (in the thyroid or neck nodal metastasis) • Rarely have problems with thyroid status (not true for all thyroid lumps) • Compressive symptoms- problems swallowing, feeling like they are being strangled • Can have voice change • Triple assessment (similar to breast lumps) – Full Hx and Ex – Imaging (ultrasound) – Needle testing of any suspicious lumps via cytology in the form of Fine Needle Aspiration Cytology (FNAC) – May need advanced Ix (treatment) • Types: – Papillary adenoCa(80%) – Follicular AdenoCa(10%) – Medullary Ca(5%) – Anaplastic Ca(5%) • Thyroidectomy (hemi or total dependant on type of Ca- most are total) • Radioactive Iodine • Radiothearphy/Chemot hearphy

Question 34

Hypopharyngeal/Laryngeal Carcinoma

Answer 34

• TNM staging • MDT meeting Management • Radiotherapy +/- chemotherapy • Surgery – Laryngectomy – Pharyngo-laryngectomy – including radical or selective neck dissections • Palliation

Question 35

Thyroid surgery

Answer 35

Thyroid Surgery • Hemi-thyroidectomy • Sub-total thyroidectomy • Total thyroidectomy • Potential for iatrogenic injury to superior laryngeal and recurrent laryngeal nerves

Question 36

Recurrent Laryngeal Nerve Palsy

Answer 36

• Idiopathic • Laryngeal cancer • Thyroid disease (benign or malignant) • Trauma (including iatrogenic – ie. thyroidectomy) • Cervical lymphadenopathy • Oesophageal cancer • Apical lung cancer • Aortic aneurysm • Neuropathic (diabetes)