H&N Benign Lesions

Question 1

What are the common aetiologies of neck masses according to age group?

Answer 1

Question 2

What are branchial arches

Answer 2

• mesenchymal swellings of mesoderm/ectoderm/endoderm that form the craniofacial structures wk 4.5
• 5-6 paired arches, Each contains
  
  • core mesoderm, ectoderm on surface and endoderm inside
  • artery (formed by mesoderm)
  • muscle (formed by mesoderm)
  • nerve
  • cartilage rod
  • ligament

Question 3

Describe the development of craniofacial structures

Answer 3

• week 3 - formed trilaminar disc and outgrowth of neuroectoderm, neural disc, neural plate and tube
• wk 4 - migration of arches to form primitive face with stomodeum between 1st arch and frontonasal prominence
• wk5 -8 - formation and coalescence of facial prominence (FNP, MxP, MdP)

Question 4

Define the derivatives of each arch, pouch, groove, cleft

Answer 4

Question 5

Describe development of thyroid

Answer 5

• wk 3, involution of epithelium (diverticulum) at tongue and ascent below hyoid, contains derivatives of thyroid
• if thin duct fails to degenerate, left with tract connected at foramen cecum

Question 6

Describe development of masses at/near nose

Answer 6

• foramen cecum usually obliterated separating anterior cranial fossa from nose
• if not obliterated, can have resulting dermoid, glioma, encephalocele

Question 7

What is your DDX for congenital nasal mass

Answer 7

dermoid

glioma

encephalocele

Question 8

What is a dermoid?

Answer 8

• epithelium lined sac containing ectoderm and mesoderm = sequestration of ectodermal remnants remaining during embryonic fusion at suture lines
• can extend intracranial
• cyst lined by squamous epithelium and contianing secretions from hair follicles, sweat/sebaceous glands

Question 9

How are dermoid classifed?

Answer 9

By location

• midline submental, nasal dorsum, columella, along brow, along suture lines

Question 10

What investigations would help in the management?

Answer 10

CT - for intracranial extension

• may identify bifid crita galli, enlarged foramen cecum, wide NF suture, bony destruction in NF region

MRI - for delineation of involved soft tissues

Question 11

What is the treatment

Answer 11

Non-operative observation

Operative

• Intracranial lesion - requires frontal craniotomy and external approach with use of lacrimal probe and skin excision if sinus present
• Extracranial only - external approach

Question 12

What is a nasal glioma?

Answer 12

• mass of EXTRAdural glial tissue on a stalk - not connected to dura/brain

Question 13

What are associated clinical findings of a nasal glioma

Answer 13

• if glioma is INtERnal: may have chronic nasal obstruction/discharge ,widened nasal base
• if glioma is EXternal - presents as noncompressible mass with no fluctuation w crying

Question 14

What is an encephalocele

How are encephaloceles classifed?

Answer 14

• herniation of meninges +/- herniation of brain tissue

By location

occipital

pareital

frontal - nasoethmoid, nasofrontal, nasoorbital

Question 15

What is the treatment

Answer 15

• excision with comines intracranial and extracranil approach
• Bicoronal, bifrontal osteotomy, exposur eof mass
• Reconstruction - dural closure (TPF, temporalis, fascia lata), bone recon of anterior cranial fossa, obliteration of cranial/nasal communication, orbital osteotomies or facial bipartition

Question 16

What is your differential diagnosis of a benign neck mass according to location?

Answer 16

MIDLINE

• laryngocele
• thyroglosal duct cyst
• ranula
• thyroid adenoma, goiter
• thymus gland lesion
• dermoid

LATERAL

• branchial cleft/cyst
• carotid body tumor (glomus tumor)
• cystic hygroma

Question 17

What is a laryngocele and how do you manage

Answer 17

abnormal dilation of the laryngeal saccule

= congenitla or acquired (2’ high intralaryngeal pressure w instruments/cough

• History: ass. gurgling, empyting/swelling, dysphagia/dysphonia
• Investigation: endoscopy and CT
• treat: excision

Question 18

What is a thyroglossal duct cyst and how do you manage

Answer 18

• persistant thryoglossal duct and resulting cyst - duct lined from base of tongue to hyoid during development o fthyroid
• presents in 2nd decase, elevates w tongue protrusion
• Need to confirm presence of normal thryoid prior to excision - U/S and TSH
• excision for tx

Question 19

What is the etiology of branchial cleft cyst/sinus/fistula

Answer 19

• failure of 2nd BA to grow caudally over 3rd ad 4th with obliteration of openings
• cyst/sinus/fistula usually found along anteriro border of SCM, below angle of manidble or preauricular

1st BA -> not common, near parotid/CN7 , if excision- use intra-op nerve stimulation and excise segment of cartilage at EAC

2nd BA-> most common, located along anterior sternal border. MAybe anywhere along tract from skin along SCM, through platysma, over CN12,9, through carotid bifurcation into tonsillar fossa

3rd,4th - rare, enter larynx

Question 20

What is the clinical presentation of a B cleft cyst/fisutla/sinus

Answer 20

• ass. UTI w pain, discharge, fluctuating or slowing increasing in size

Question 21

What is a glomus tumor

Where are they located in the head and neck

Answer 21

Benign neuroendocrine mass, also known as a paraganglioma

• Carotid bifuration
• Jugular bulb at skull base - most common
• Vagus nerve
• Middle ear cavity

Question 22

What are treatment options?

Answer 22

embolization

excision