ESTADO FINAL DE LA OBRA
2.10.5 TRABAJO VOLUNTARIO
1. Submental lymph node 2. Thyroglossal cyst
3. Thyroid nodule in the isthmus 4. Sublingual dermoid cyst
5. Plunging ranula (retention cyst of the sublingual) 6. Rarely, hyoid pathology e.g. bursa
Anterior triangle
1. Lymph node – along anterior border of sternocleidomastoid (levels II, III, IV) 2. Thyroid nodule
3. Submandibular gland mass (see later section on Salivary gland swellings) 4. Branchial cyst + fistula
5. Chemodectoma (carotid body tumour) 6. Carotid aneurysm
7. Pharyngeal pouch
8. Laryngocoele (rare; an air-filled, compressible structure seen in glass-blowers) Posterior triangle
1. Lymph node (mainly) – level V and supraclavicular lymph node groups 2. Cystic hygroma
3. Cervical rib
4. Brachial plexus neuroma/schwannoma
Approach:
- Does it move with swallowing – divides the thyroglossal cyst and thyroid nodule from the other causes
- If it moves with swallowing, does it move with tongue protrusion – thyroglossal cyst moves with protrusion but a thyroid nodule does not
2. THYROGLOSSAL CYST
Epidemiology:
Equal in males and females. Occurs mostly in children and adolescents but up to one-third occur in patients older than 20 years.
Pathology:
Cystic expansion of the remnant thyroglossal tract (embryological origin of the thyroid which descends from the foramen caecum on the tongue).
Features:
Smooth, rounded, cystic lump.
75% are in the midline while 25% are slightly to the left or right. Usually asymptomatic but may become infected.
Complications:
1. Infected with sinus formation and seropurulent discharge (occurs with incision or rupture of cyst) 2. Malignant change (carcinoma of the thyroglossal duct)
Histology:
Cyst with columnar or squamous epithelial lining which may be ciliated.
The cyst may also contain thyroid and lymphoid tissue. If malignancy occurs, it is usually a papillary carcinoma (~90%).
Treatment:
Sistrunk procedure – resection of the (a) cyst and (b) mid-portion of the hyoid bone in continuity and resection of a (c) core of tissue from the hyoid upwards towards the foramen caecum (remove the entire tract to prevent recurrence!)
3. DERMOID CYST
Pathology:
Can be congenital or acquired.
(i) Congenital – developmental inclusion of epidermis along lines of fusion of skin dermatomes (seen in younger patients, present since birth). Locations include:
o medial and lateral ends of the eyebrows (internal and external angular dermoid cysts) o midline of the nose (nasal dermoid cysts)
o midline of the neck and trunk
(ii) Acquired – due to forced inclusion of skin into subcutaneous tissue following an injury, usually on fingers. Seen in older patients, no previous history of mass, history of trauma to area (may have associated scar).
Histology:
Cyst lined by epidermis, with evidence of adnexal structures such as hair follicles, sebaceous glands and sweat glands.
Features:
Small non-tender mobile subcutaneous lump, may be fluctuant, skin-coloured or bluish.
Management
- Imaging investigations (e.g. XR, U/S, CT) are important especially for cysts on the skull as they can communicate with cerebrospinal fluid. - Complete surgical excision of the cyst.
4. PLUNGING RANULA
Pathology:
A pseudocyst associated with the
sublingual glands and submandibular ducts. Ranulas (frog mouth) can be congenital or acquired after oral trauma.
Typically appears as a blue-grey dome-like swelling beneath the tongue.
A large ranula can present as a neck mass if it extends through the mylohyoid musculature of the floor of the mouth – termed a “plunging” ranula.
Treatment:
- Complete resection if possible, often in continuity with assoc sublingual gland
(but often difficult due to close association with the lingual nerve and submandibular duct).
- If complete resection not possible, marsupialisation (de-roofing the cyst so that it opens into the floor of the mouth) and suturing of the pseudocyst wall to the oral mucosa may be effective.
Incomplete removal leads to recurrence.
5. BRANCHIAL CYST/FISTULA
Epidemiology:
Affects both sexes equally, usually in young adults in their 20s.
Pathology:
A branchial cyst is thought to develop because of failure of fusion of the embryonic second and third branchial arches. It is lined by squamous epithelium.
Features:
- Occurs anterior to the upper or middle third of the sternocleidomastoid muscle.
- Smooth firm swelling that is ovoid in shape, with its long axis running downwards and forwards. - May be fluctuant, usually not transilluminable (due to desquamated epithelial cell contents).
- Look for fistula in this area – a branchial fistula will run between tonsillar fossa and the anterior neck, passing between the external and internal carotid arteries.
- Fine needle aspiration of the cyst will yield opalescent fluid with cholesterol crystals under microscopy. - May be complicated by recurrent infections – purulent discharge, fixation to surrounding structures.
Management:
- If fistula present, perform fistulogram to delineate course.
- Surgical excision of the cyst where possible. (perc drainage rarely permanently successful)
If fistula/sinus present, inject Bonney’s blue dye into tract prior to surgery to allow accurate surgical excision. - Treatment of infection with antibiotics.
- Complications: cyst recurrence; chronic discharging sinus.
6. CHEMODECTOMA
Pathology:
A chemodectoma is a tumour of the paraganglion cells (paraganglionoma) of the carotid body located at the bifurcation of the common carotid artery (into the internal and external carotids).
They are usually benign, but locally invasive; the risk of malignancy is 10%, with metastasis to local lymph nodes (no histopathological features for malignancy, thus malignant nature can only be diagnosed by presence of metastasis).
Features:
- Solid, firm mass at the level of the hyoid bone (where the bifurcation is) – be gentle during palpation as pressure on the carotid body can cause vasovagal syncope.
- Mass is pulsatile but not expansile, due to transmitted pulsation from carotids.
- Due to close association with carotid arteries, lump can be moved side to side but not up and down. - May be bilateral.
Differentials:
- Main differential is carotid artery aneurysm
- Aneurysm can occur at any level but carotid body tumour occurs at the level of the hyoid bone.
- If suspecting aneurysm, (a) listen for bruit, look for (b) signs of Horner’s syndrome, (c) examine the rest of the peripheral vascular system.
Investigation:
- DO NOT PERFORM FNA
- Angiography (gold standard) – shows a hypervascular mass displacing the bifurcation. May also show vessel compromise by tumour invasion, and undetected synchronous tumours.
- CT and/or MRI can be used to delineate tumour anatomy in relation to surrounding structures; CT reveals homogenous mass with intense enhancement following IV contrast administration.
Treatment:
- Surgical excision with pre-operative embolisation (reduces bleeding and complications, and facilitates resection); any enlarged ipsilateral lymph nodes are also removed due to the small possibility of malignancy
- Radiotherapy is an effective alternative for patients who are unfit for surgery or whose tumours are too large.
7. PHARYNGEAL POUCH
Pathology:
A herniation of the pharyngeal mucosa (pulsion diverticulum) through its muscular coat at the weakest point – Killian’s dehiscence – between the cricopharyngeus muscle and the lower inferior constrictor muscles.
Features
- Occurs in older patients
- A cystic swelling low down in the anterior triangle, usually on the left - Squelching sound on deep palpation
- Patient complains of o halitosis,
o regurgitation of undigested food with coughing o dysphagia in the neck,
o hoarseness, o weight loss
- Complications: aspiration pneumonia; diverticular neoplasm (<1%)
Diagnosis by barium swallow Treatment
- Leave it alone if small and asymptomatic
- Minimally invasive treatment: endoscopic cricothyroid myotomy - Surgical approaches (several available)
o Diverticulectomy + cricothyroidotomy (diverticulectomy associated with risk of mediastinitis, dangerous)
o Diverticulopexy (done in high risk patients, involves suspending the lumen of the pouch in the caudal direction so that food and secretions cannot enter the pouch; as the diverticulum is still present, the risk for malignancy still remains)
8. CYSTIC HYGROMA
Pathology:
A cystic hygroma is a congenital cystic lymphatic malformation found in the posterior triangle of the neck, probably formed during coalescence of primitive lymph elements. It consists of thin-walled, single or multiple interconnecting or separate cysts which insinuate themselves widely into the tissues at the root of the neck.
Features:
- 50-65% present at birth, but occasionally may present later in childhood or adulthood
- cystic swelling that is soft, fluctuant, and compressible (usually into another part of the cyst), located in the posterior triangle at the root of the neck
- Classically “brilliantly transilluminable”
- A large cyst may extend deeply into the retropharyngeal space
Complications:
- Cystic hygroma seen on prenatal ultrasound in the first trimester suggests chromosomal abnormality (50% of foetuses, usually trisomy 21) or other structural abnormalities (33% of foetuses with no chromosomal abnormality, usually congenital heart anomalies)
- May obstruct delivery
- Compressive problems after delivery – respiratory, swallowing
Management:
- Radiological investigations e.g. CXR, CT to delineate extent of cyst
- Non-surgical treatment – aspiration and injection of sclerosant (usually unsuccessful) - Surgical excision – partial (to alleviate symptoms) or complete
9. CERVICAL RIB
Features:
- Usually more symptoms than signs as it causes thoracic outlet syndrome (diagram below) - A hard mass in the posterior triangle at the root of the neck
- Symptoms/signs:
o Arterial: pallor, gangrene or necrosis of the tips of the fingers o Venous: oedema, cyanosis
o Neurological: complaints of radicular symptoms (pain, paraesthesia), wasting of the small muscles of the hand
- Adson’s test can be done – ask patient to extend neck and rotate it towards side of symptoms radial pulse will be diminished, occasionally with reproduction of radicular symptoms in the limb
- Diagnosis by CXR
10. NEUROMA/SCHWANNOMA
Features:
- Slow growing tumour arising from peripheral neural structures of the neck e.g. brachial plexus, cervical plexus, vagus nerve, phrenic nerve, etc.
- Fusiform, is mobile in plane perpendicular to axis of nerve but not parallel - Usually benign
- May be Tinnel’s positive – tap on the mass for any paraesthesia occurring in distribution of the nerve - DO NOT PERFORM FNA – excruciatingly painful