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Lymph Node Excision Biopsy
https://t.me/med1917
VictoriaHarries andAshleyHay
8.1 Introduction
The head and neck region includes over 200 lymph nodes [1]. Lymph nodes are a major constituent part of the lym­phatic system and are formed from multiple types of lym­phoid cells [2]. The lymphatic system functions to drain the lymphatic uid in a one-way network of lymphatic vessels [3] and allows the lymphatic cells to perform a vital and complex immunological function [4]. Enlargement of one or more lymph nodes is a common presentation that can indi­cate a vast number of benign or malignant conditions.
A cervical lymph node biopsy may be needed in some instances to establish or conrm a diagnosis. In other situa­tions, however, an open cervical biopsy is not recommended and can be harmful. Therefore, a thorough understanding of the differential diagnosis and appropriate investigational strategy is essential before performing a surgical or open lymph node biopsy.
A differential diagnosis is formed by assessing a full his­tory and examination with appropriate workup, as indicated by patient’s age, risk factors, and physical ndings. A broad differential diagnosis includes reactive lymphadenopathy from bacterial or viral causes, head and neck malignancies, haematological malignancies, and metastatic deposits from other primaries outside of the head and neck.
An open cervical biopsy in patients with metastatic squa­mous cell carcinoma or a diagnosis of tuberculosis (TB) in the lymph node can lead to suboptimal outcomes. An open biopsy of squamous cell carcinoma can lead to disease in the cutaneous tissues, and biopsy of a TB lymph node can lead to a chronic draining stula (Fig.8.1).
V. Harries Department of Otolaryngology, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
A. Hay (*) Department of Otolaryngology, University of Edinburgh, NHS Lothian’s University Hospitals Division, Edinburgh, Scotland e-mail: ashley.hay@nhs.net
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Fig. 8.1 Cervical tuberculosis discharging through a neck wound
(scrofula)
Recent advances in ultrasound technology have made it possible to assess the structure of cervical lymph nodes in detail, enabling accurate diagnosis of even small lesions and targeted sampling with ne-needle aspiration (FNA) or core biopsies. Ultrasound and FNA are safe and inexpensive investigations that reliably detect suspicious and malignant cervical adenopathy, without risk of seeding the cutaneous tissues. In the workup of any cervical lymphadenopathy, an ultrasound and FNA cytology is a pivotal investigation [5]. In some instances, however, an open biopsy is required. In the diagnosis of lymphoma, the architecture of the node is often required for an accurate diagnosis. In nodes with unequivocal or insufcient FNA cytology results, open biopsy might be needed for diagnosis, and if non-squamous malignant cells are found on cytology, further tissue may be required to aid the search for a primary tumour by providing more tissue to be interrogated with immunohistochemical tests.
© Springer Nature Switzerland AG 2024 R. Simo et al. (eds.), Atlas of Head and Neck Surgery, Springer Surgery Atlas Series,
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V. Harries and A. Hay
Knowledge of the anatomy of the neck and cranial nerves is fundamental to performing an open cervical biopsy. The surgical approach and technique varies according to the loca­tion of the lymph node and the nerves potentially at risk. For a diagnostic procedure, the risks of any negative sequelae should be minimized. The nature of a lymph node biopsy is often presumed to be straightforward, but this procedure can be underestimated and may become difcult, involving small incisions and lymph nodes that are often bigger, deeper, and closer to major vessels or nerves than initially appreciated.
8.2 Preoperative Checklist
andConsiderations
8.2.1 History andExamination
A comprehensive ENT history and examination are essential to ensure that the necessary investigations have been consid­ered and to identify patients who require an excisional biopsy. A detailed history of the neck swelling should be taken to ascertain the duration, location, and any change in size.
Associated symptoms and constitutional symptoms should also be elicited in the history. Associated symptoms related to the head and neck, such as dysphagia, hoarseness, odynophagia, unilateral sore throat, and otalgia, are all sig­nicant and require a detailed investigation of the upper aerodigestive tract.
Constitutional symptoms such as fatigue, weight loss, and tiredness may indicate a disseminated disease process. Type B symptoms such as night sweats, pruritis, and loss of appetite can indicate lymphoma. The patient’s smoking sta­tus and alcohol history should also be recorded, in addition to any previous head and neck malignancies or radiation. A recent travel history and social contacts with any unwell family members or friends is also important, to identify potential infective causes.
A physical examination should include palpation of the neck to conrm the location, consistency, and mobility of the enlarged lymph node. A hard, xed lymph node is suggestive of carcinoma, whereas a mobile, rubbery node is typical of lymphoma. A detailed examination includes inspection and palpation of the oral cavity and a exible nasoendoscopy (FNE) examination of the postnasal space, tongue base, hypopharynx, and larynx, to assess for a cause in the upper aerodigestive tract.
The location of the lymph node can suggest the potential site of primary pathology, because the lymphatic system has predictable drainage pathways. An enlarged lymph node in
the supraclavicular fossa should be evaluated with a high index of suspicion and can often indicate intra-abdominal malignancy [6].
8.2.2 Investigations
Appropriate investigations depend on the ndings from the history and examination. The rst-line investigation for a suspicious neck mass in most cases is ultrasound and FNA (Fig.8.2). Further imaging that is tailored to the differential diagnosis can include chest radiography, CT scans, MRI, or positron emission tomography (PET).
An ultrasound scan assesses the nodal architecture, hilar shape, and internal vascularity, to identify malignant lymph nodes. Reactive lymph nodes usually appear enlarged but have a well-dened and retained reniform shape and echogenic hilum. Rounded nodes, nodes with central necrosis and loss of hilar architecture, and nodes increasing in size are all features indicating malignancy [7, 8]. Additional features can be specic to a diagnosis, such as intranodal microcalcication, which is suggestive of a metastatic papillary thyroid lymph node [9].
If malignancy is not high in the differential diagnosis, blood tests should be considered to identify an infective cause. Examples include a peripheral blood smear, full blood count (FBC), erythrocyte sedimentation rate (ESR), lactate dehydrogenase (LDH), Mantoux skin test, and serology test­ing for toxoplasmosis, cytomegalovirus (CMV), Epstein­Barr virus (EBV), Brucella, and Bartonella.
Fig. 8.2 Ultrasound-guided ne-needle aspiration (FNA) of a lymph node
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8.2.3 Anatomy andAnatomical Considerations
The lymphatic system of the head and neck can be divided into the supercial and deep network by the deep cervical fascia. The supercial lymphatics drain the skin of the head and neck into the suboccipital, preauricular, postauricular, and external jugular lymph nodes, and, ultimately, into the deep jugular lymph nodes. The deep lymphatics drain the mucous membranes of the upper aerodigestive tract, thyroid, and larynx directly into the deep cervical lymph node chains.
The neck can be divided into the anterior and posterior triangles, bounded by the layers of the deep cervical fascia (Fig. 8.3). The boundaries of the anterior triangle are the inferior border of the mandibular ramus superiorly, the ante­rior border of the sternocleidomastoid muscle laterally, and the midline. The posterior triangle is bounded by the poste­rior border of the sternocleidomastoid medially, the clavicle inferiorly, and the anterior border of the trapezius laterally. The posterior triangle contains the cutaneous branches of the cervical plexus, spinal accessory nerve, and the transverse cervical and suprascapular vessels.
The American Academy of Otolaryngology and Head and Neck Surgery (AAO-HNS) and the American Joint Committee on Cancer (AJCC) have developed a widely accepted classication of cervical lymph node levels [10, 11] (Fig. 8.4), after the description of neck drainage from Memorial Sloan Kettering Cancer Center [12].
8.2.4 Structures at Risk During Lymph Node Biopsy
8.2.4.1 Accessory Nerve
The accessory nerve is a pure motor nerve that supplies the sternocleidomastoid (SCM) and trapezius muscles. The spi­nal and cranial roots of the accessory nerve exit the cranium through the jugular foramen. As the nerve exits the skull base and enters the neck, it lies between the internal carotid artery and internal jugular vein. It descends obliquely, usually run­ning supercial to the internal jugular vein but in rare cases running dorsal to it. The nerve travels along the levator scap­ulae before reaching the upper part of the SCM.It descends obliquely to reach the upper part of the SCM and passes deep to or through the SCM to enter the posterior triangle. It can therefore be injured in the anterior triangle and in the poste­rior triangle during a lymph node biopsy.
In the anterior triangle, the transverse process of C1 can be a useful landmark, as it is palpable in most people. The internal jugular vein is found anterior to it. Careful dissection of this area exposes the posterior belly of the digastric mus­cle and then allows safe identication of the internal jugular vein and accessory nerve. In addition, deep to the posterior border of the posterior belly of the digastric muscle lies the hypoglossal nerve.
Erb’s point, at the junction between the upper third and lower two thirds on the posterior border of the SCM muscle, marks the point where the branches of the cervical plexus
Fig. 8.3 The different anatomical triangles in the neck
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Fig. 8.4 The American Joint Committee on Cancer (AJCC) classication of cervical lymph node levels
V. Harries and A. Hay
II
I
B
I
A
B
II
A
exit. The accessory nerve exits the SCM to enter the poste­rior triangle about 1cm behind Erb’s point.
In the posterior triangle, the nerve is supercial; it can be found just beneath the subcutaneous fat and is at risk of injury in this location. The accessory nerve ultimately reaches the anterior border of the trapezius muscle, entering the muscle on the undersurface. The nerve is at high risk of injury in the posterior triangle, because it is supercial, it is small, and there are no xed anatomical points. Lymph nodes that are frequently the focus for biopsy run in a chain around the nerve and often are in contact with it.
8.2.4.2 Marginal Mandibular Nerve
The marginal mandibular nerve is a branch of the facial nerve, which provides motor innervation to the lower lip and chin. The nerve exits the inferior portion of the parotid gland and courses deep to the supercial layer of the cervical fas­cia. It runs across the mandible close to the the bony notch made by the facial artery. It then ascends to the corner of the mouth more anteriorly [13]. It is supercial to the facial artery and vein, and to the submandibular gland. It can be injured when raising the skin ap or if the skin incision is too close to the mandible.
The marginal mandibular branch runs within 1.5cm of the inferior border of the mandible, but can be found along or above the border of the mandible. Common practice to avoid injury to the nerve is for a skin incision to be at least two
VI
III
IV
V
A
V
B
ngerbreadths below the mandible. Injury to this nerve results in an asymmetric smile due to loss of the angularis depressor muscle and impaired lower lip movement inferiorly.
8.2.4.3 Hypoglossal Nerve
It is rare for the hypoglossal nerve to be injured during a lymph node biopsy. It exits the skull base through the hypo­glossal canal posteriorly in the skull. It then travels inferiorly adjacent to the vagus nerve and spinal division of the acces­sory nerve in the carotid sheath. It then passes behind the vagus nerve and passes between the internal carotid artery and internal jugular vein. It travels in a deep plane, beneath the posterior belly of the digastric muscle. The gentle curve in the nerve is created by the occipital artery looping over the nerve. It then enters the tongue at the junction of the anterior two thirds and posterior third of the tongue, between the hypoglossus muscle deep and the stylohyoid muscle and lin­gual nerve supercially. It then supplies the motor innerva­tion to the extrinsic and intrinsic muscles of the tongue.
8.2.4.4 Thoracic Duct andAccessory ThoracicDuct
The thoracic duct on the left and the accessory thoracic duct on the right are at risk of injury if a lymph node to be sam­pled is in Level IV or in the supraclavicular fossa. The tho­racic duct is located deep behind the lymph nodes in this
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region, but it can become dilated in high-volume disease, which can increase the risk of injury. It drains into the venous circulation at the conuence of the internal jugular vein and subclavian vein. Its passage is highly variable, with a looping course superior before returning inferior to empty into the internal jugular vein. It can be found in a triangle between the phrenic nerve, internal jugular vein, and subclavian vein.
8.2.4.5 Major Cervical Vessels
Lymph nodes can be closely apposed to the major vessels, particular the internal jugular vein. The carotid and its major branches have a thick vascular wall and are usually resistant to invasion. The internal jugular vein is more commonly invaded or affected by brosis from pathological processes in adjacent lymph nodes. It also has a thin wall and is at risk during surgery.
8.2.4.6 Phrenic Nerves
These are found on the prevertebral muscles. They are usu­ally protected by the prevertebral fascia overlying the cervi­cal rootlets. They are identied as the only nerves to have a lateral-to-medial direction.
8.3 Indications
A number of situations are indications for excisional lymph node biopsy:
identication and location of the suspicious node, but this technique is infrequently needed. Close study of preopera­tive imaging, such as a CT scan, also can be very helpful.
8.4.1 Anaesthetic Considerations
An excisional lymph node biopsy can be performed under general or local anaesthetic. Local anaesthetic allows for a shorter recovery period and avoids any individual risks asso­ciated with general anaesthetic. The procedure can be easily underestimated, however, as all major structures in the neck are in close proximity, and small incisions for a biopsy can be inadequate to fully expose the anatomy. The threshold for general anaesthetic should therefore be low, especially for deep jugular chain lymph nodes. A general anaesthetic also allows for nerve monitoring if an incisional parotid biopsy is being performed.
8.4.2 Patient Positioning andDraping
Position the patient supine with a shoulder roll for neck extension and the head on a doughnut or ring to support the occiput (Fig.8.5). Putting the operating table with the head up at approximately 30–45° helps reduce bleeding, improves access, and can help ventilation (Fig.8.6). The neck can be draped using a head drape, or the area can be squared draped.
• Non-diagnostic FNA and/or core biopsy results
• Suspected lymphoma (for architecture information or diagnosis of low-grade lymphomas)
• Persistent paediatric cervical lymphadenopathy with sus­picious features on imaging
• HIV cervical lymphadenopathy of unknown cause
• Non-squamous malignancy in which further tissue is required for immunohistochemistry
8.4 Surgical Technique
The consent process involves a thorough explanation to the patient of the need for the procedure and the likely effect if it is not performed. The risks of the procedure should be explained, with the explanation tailored to the patient and the operation, taking reasonable care to ensure that the patient is aware of all material risks [14].
The lymph node identied on ultrasound and subsequent
FNA should be targeted for evaluation, because if the FNA suggested a malignant process, sampling adjacent nodes may show only reactive changes. Lymph nodes that are small can be identied preoperatively with ultrasound guidance to aid
8.4.3 Skin Incision
Determine the direction of Langer’s lines and mark a trans­verse skin crease incision. Use an existing skin crease where possible, to improve the cosmesis of the scar (Fig.8.7). Take into consideration whether the patient may need to undergo a subsequent neck dissection.
Fig. 8.5 Position of a shoulder roll and head ring
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Fig. 8.6 Position of the bed, with bed broken in centre to allow head up 30–45° and extension of the atlanto-occipital joint
Fig. 8.8 To expose the lymph node, the sternocleidomastoid muscle (SCM) is identied after subplatysmal aps are raised
V. Harries and A. Hay
Fig. 8.7 Skin crease incision used for Level II cervical lymph node biopsy
subcutaneous
tissues
Platysma muscles
Strap muscles
8.4.4 Elevation ofFlaps
Raise small subplatysmal aps and divide the cervical fascia overlying the node. Careful dissection is required in the pos­terior triangle and at Level II in the anterior triangle to mini­mize the risk to the accessory and marginal mandibular nerves, given their supercial locations.
Cervical nodal mass beneath deep cervical fascia
Sternocleidomastoi muscle
8.4.5 Exposing theLymph Node
Identifying the lymph node depends on its position and the related structures. In most circumstances, the identication of the sternocleidomastoid muscle allows for lymph node identica­tion (Fig. 8.8). Once the capsule of the lymph node has been identied, the plane above the capsule should be dissected in all
Digastric
d
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Fig. 8.9 Fully mobilized lymph node at point of excision
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muscle
Strap muscles
Carotid artery
Vagus nerve
Internal jugular vein
Cervical nodal mass
Sternocleidomastoi muscle
directions, gradually increasing the mobility of the node. A small area of fascia can be left attached to the node so that it does not need to be directly handled, which can cause the nodal capsule to tear. A mixture of sharp and blunt dissection can be used, with careful bipolar or monopolar cautery for haemostasis. The aim is to completely excise an intact lymph node (Fig.8.9).
8.4.6 Haemostasis
Ligate or cauterize any visualized vessels. A Valsalva manoeuvre can be used to check for haemostasis at the end of the procedure. Drain insertion is not routinely required but should be considered. Haemostatic agents such as Surgicel can be used, especially if there is general low-pressure ooze from divided lymphoid tissue.
8.4.7 Skin Closure
The platysmal layer is closed with interrupted 3-0 Vicryl sutures. A continuous subcuticular absorbable suture to skin with 4-0 Monocryl sutures can be used to create a satisfac­tory cosmetic outcome.
8.4.8 Specimen
Special consideration for the specimen should be taken in close liaison with the pathology and microbiology depart-
ment. Specimens for microbiology examination need to be fresh and sterile. Potential TB cultures should be examined with specic stains, especially Ziehl–Neelsen (ZN) stain. In lymphoma, the specimen may be required fresh so that ow cytometry can be performed. For standard histological examination, the xing agent preferred by the laboratory should be used.
8.4.9 Specic Lymph Node Biopsy Techniques
8.4.9.1 Parotid Biopsy
A mass in the parotid gland usually should be removed with a formal superficial parotidectomy, in which the facial nerve branches are identified so that they are pro­tected from injury. Parotidectomy may be needed for diagnostic purposes in cases of equivocal cytology or if a low-grade lymphoma is considered. However, the parotid gland has abundant lymphoid tissue, and patients can present with large, rapidly growing masses (Fig.8.10). In these situations, a formal parotidectomy or lymph node biopsy is not possible. The potential for a high-grade lymphoma needs to be ruled out and a biopsy is required. In these instances, an incisional biopsy may be performed.
To minimize injury, an incision should be marked out par­allel to any nerve branches. Very slow and judicious dissec­tion should be used to expose the lesion. A facial nerve monitor may be benecial in these circumstances.
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Fig. 8.10 Patient with large and rapidly growing parotid mass
8.4.9.2 Jugular Digastric Nodes
The lymph node position in the anterior triangle can be either anterior to the SCM or deep and adjacent to the carotid sheath and jugular vein. For anterior nodes or large nodes, exposure of the anterior border of the SCM with lateral retraction will allow access for node removal. The SCM can be retracted well with a Langenbeck retractor or Richardson retractor to optimize access (Fig. 8.11). For deeper nodes, the access required to allow for retraction of the SCM may require a large incision, but another option is a muscle­splitting approach. This works in large-volume disease that has splayed the muscle and makes retraction through a biopsy incision difcult. The muscle can be split in line with its bres. To avoid injury, care must be taken to understand the position of the accessory nerve. The use of a self- retaining retractor (Fig.8.12) can be helpful for this approach.
8.4.9.3 Posterior Triangle Nodes
The lymph nodes in the posterior triangle are either part of the chain running with the accessory nerve in the superior aspect of the triangle or they are in the supraclavicular area. The spinal accessory nerve is very supercial in the posterior triangle, often just deep to skin, because there is no platysma muscle in this area.
Supraclavicular nodes often can be large and xed below the clavicle, with close involvement of the lymphatic vessels and thoracic duct. These nodes often are sampled with an incisional biopsy.
Fig. 8.11 Sternocleidomastoid muscle retracted laterally to give access to Level II lymph node
Fig. 8.12 A self-retaining retractor
8.5 Postoperative Care
8.5.1 Complications
Damage to the marginal mandibular branch of the facial nerve leads to reduced motor function of the ipsilateral side of the lower lip, which can be associated with an asymmetric smile.
Injury to the accessory nerve leads to shoulder pain and weakness. These symptoms can be reduced with physiotherapy.
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Damage to vessels can cause intraoperative and postop­erative bleeding. If excessive bleeding has occurred or if there has been extensive dissection, there should be a low threshold for drain insertion at the end of the procedure and inpatient admission.
Other nonspecic complications can include formation of hypertrophic/keloid scars, numbness, and wound dehiscence or infection.
8.5.2 Follow-Up
Patients should be sent home with wound care and suture advice, analgesia, and a follow-up appointment for a review of the histology results. Appropriate onward referral depend­ing on the pathology or microbiology ndings should then be made.
References
1. Trotter HA.Surgical anatomy of the lymphatics of the head and neck. Ann Otol Rhinol Laryngol. 1930;39:384–97.
2. Alex JC.The head and neck lymphatic system. Facial Plast Surg Clin North Am. 2003;11:43–7.
3. Rouvière H, Valette G.Physiologie du système lymphatique. Paris: Masson; 1937.
4. Willard-Mack CL. Normal structure, function, and histology of lymph nodes. Toxicol Pathol. 2006;34:409–24.
5. McQueen AS, Bhatia KS. Head and neck ultrasound: technical advances, novel applications and the role of elastography. Clin Radiol. 2018;73:81–93.
6. Baumgart DC, Fischer A. Virchow’s node. Lancet. 2007;370(9598):1568.
7. Papakonstantinou O, Bakantaki A, Paspalaki P, Charoulakis N, Gourtsoyiannis N. High-resolution and color Doppler ultraso­nography of cervical lymphadenopathy in children. Acta Radiol. 2001;42:470–6.
8. Ying M, Bhatia KS, Lee YP, Yuen HY, Ahuja AT.Review of ultra­sonography of malignant neck nodes: greyscale, Doppler, contrast enhancement and elastography. Cancer Imaging. 2014;13:658–69.
9. Azar N, Lance C, Nakamoto D, Michael C, Wasman J. Ultrasonographic thyroid ndings suspicious for malignancy. Diagn Cytopathol. 2013;41:1107–14.
10. Robbins KT, Clayman G, Levine PA, Medina J, Sessions R, Shaha A, etal. Neck dissection classication update: revisions proposed by the American Head and Neck Society and the American Academy of Otolaryngology-Head and Neck Surgery. Arch Otolaryngol Head Neck Surg. 2002;128:751–8.
11. Robbins KT, Medina JE, Wolfe GT, Levine PA, Sessions RB, Pruet CW. Standardizing neck dissection terminology. Ofcial report of the Academy’s Committee for Head and Neck Surgery and Oncology. Arch Otolaryngol Head Neck Surg. 1991;117:601–5.
12. Spiro RH, Strong EW, Shah JP.Classication of neck dissection: variations on a new theme. Am J Surg. 1994;168:415–8.
13. Baur DA, Kaiser AC, Leech BN, Landers MA, Altay MA, Quereshy F.The marginal mandibular nerve in relation to the inferior border of the mandible. J Oral Maxillofac Surg. 2014;72:2221–6.
14. Fryar C. Clarifying the Montgomery judgment. BMJ. 2015;350:h2217.
Thyroglossal Duct Cyst
Foramen cecum
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KarticRajaram, JoelSmith, andOmarHilmi
9.1 Introduction
The thyroid gland appears in the embryo as a midline struc­ture on approximately the 24th day of gestation; it projects downwards from the oor of the pharynx at the point that corresponds to the foramen cecum in adults [1]. It descends early in foetal life towards its position in the lower neck, with the isthmus lying over the second and third tracheal rings. This tract, known as the thyroglossal duct, maintains its attachment to the base of the tongue. At the time of its descent, the hyoid bone is not yet formed. The hyoid bone divides this tract into upper and lower segments (Fig.9.1). Hence, the track of descent could be passing in front of, through, or behind the eventual position of the hyoid body [2]. During the second embryologic month, the thyroid gland assumes its nal position anterior to the trachea, at which time the tract is resorbed.
Thyroglossal duct cysts represent a persistence of this tract and may be found anywhere in or adjacent to the mid­line from the tongue base to the thyroid isthmus. Rotation of the hyoid bone during its development causes the thyroglos­sal duct to be drawn posteriorly and cranially at the inferior margin of the bone (see Fig.9.1). Fusion of the second bran­chial arch in the midline may result in entrapment of the thy­roglossal duct by the hyoid bone.
Failure of the resorption process or the presence of retained epithelial nests along the tract forms the basis for
9
Hyoid bone
Thyroglossal
duct cyst
Pyramidal lobe
thyroid
Fig. 9.1 Sagittal view of a thyroglossal cyst, showing the relationship between the tract and the thyroid
K. Rajaram Department of Maxillofacial and Reconstructive Surgery, Manchester University NHS Foundation Trust, Manchester, UK
J. Smith Department of ENT, Head, Neck and Thyroid Surgery, Royal Devon and Exeter Foundation Trust, Nufeld Health, Exeter Hospital, Exeter, UK
O. Hilmi (*) Department of Otolaryngology, Glasgow Royal Inrmary, Glasgow, UK e-mail: omar.hilmi@ggc.scot.nhs.uk
© Springer Nature Switzerland AG 2024 R. Simo et al. (eds.), Atlas of Head and Neck Surgery, Springer Surgery Atlas Series,
https://doi.org/10.1007/978-3-031-36593-5_9
the development of a thyroglossal duct cyst. These cysts are found (in order of frequency [3]) beneath the hyoid bone, above the hyoid bone, or at the level of the hyoid bone.
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