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Midline Cervical Swellings
MahmoudSakr
9
9.1 Introduction
Neck swellings represent a very important entity
in the surgical practice. Sticking to the denition,
a neck swelling should include any mass that
presents in the neck whatever its origin is.
However, for the sake of classication, neck
swellings described in this chapter will not
include masses arising from the thyroid gland,
parathyroid glands, salivary glands, pharynx, larynx, or lymph nodes, as these entities are detailed
in separate chapters. Accordingly, diseases of
such organs will be mentioned in this chapter
only by name, so that differential diagnosis is
complete.
Swellings of the neck are generally categorized into two groups; midline and lateral neck
swellings. Midline neck swellings include those
few swellings which clinically present in the
neck midline from the submental triangle just
below the chin above to the supra-sternal notch
below. Swellings which do not respect this anatomical imaginary midline are termed lateral
neck swellings, whether presenting in the anterior or posterior triangles.
Midline and lateral neck swellings may be
further classified in different ways. They may
be classified as solid versus cystic, congenital
M. Sakr (*)
Department of Surgery, Faculty of Medicine,
Alexandria University, Alexandria, Egypt
versus acquired, or according to the anatomical subregion of presentation. It should be
noted that approximately half of all neck
masses seen in a general hospital are of thyroid origin [1].
9.2 Surgical Anatomy
9.2.1 Triangles oftheNeck
From a surgical perspective, the neck is usually
divided into two triangles: the “anterior triangle,”
which consists of three and half triangles and the
“posterior triangle,” which consists of two
triangles.
9.2.1.1 Anterior Triangle
The anterior triangle of the neck is bounded by
the anterior border of the sternocleidomastoid
(SCM) muscle laterally, the inferior border of the
mandible superiorly, and the midline of the neck
medially. In clinical practice, the structures deep
to the SCM muscle are considered to be inside
the anterior triangle. The anterior triangle consists of three and a half triangles; namely digastric (submandibular) triangle, carotid triangle,
muscular triangle, and half of the submental triangle. The midline of the neck extends from the
“symphysis menti” above to the “supra-sternal
notch” below (Fig.9.1).
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024
M. Sakr (ed.), Head and Neck and Endocrine Surgery,
https://doi.org/10.1007/978-3-031-64102-2_9
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187
188
Fig. 9.1 Triangles of the neck: Anterior triangle (submental, digastric, carotid and muscular triangles) and posterior
triangle (occipital and subclavian triangles)
M. Sakr
9.2.1.2 Posterior Triangle
The posterior triangle of the neck is bounded by
the posterior border of the SCM muscle anteriorly, the anterior edge of the trapezius muscle
posteriorly, and the middle one-third of the clavicle inferiorly. The union of the SCM and trapezius muscles at their insertion on the superior
nuchal line of the occipital bone forms the apex
of the triangle. The posterior triangle consists of
two triangles, occipital triangle and subclavian
(supra-clavicular) triangle [1, 2] (Fig.9.1).
9.3 Diagnosis ofaNeck Mass
A complete history-taking with full head and
neck examination is crucial to reach a proper
diagnosis of a cervical swelling. In children, most
neck masses are inammatory or congenital.
However, in adults, a neck mass more than 2cm
in diameter has more than 80% probability of
being malignant.
Fine-needle aspiration (FNA), preferably
guided by ultrasound (US) or computed tomography (CT), can provide a valuable tool for diagnosis and early treatment planning that provides
less oncological disruption to a tissue mass than
an open biopsy. The use of CT scan and/or magnetic resonance imaging (MRI) is dictated by the
patient’s presentation. An open biopsy may be
the last resort for reaching a proper diagnosis and
plotting a therapeutic plan. Putting the skin incision for such a biopsy should take into consideration the possibility of performing a future neck
dissection, composite resection, and/or a major
reconstruction.
Midline cervical swellings may be supercial
or deep to the cervical deep fascia (DF). Swellings
supercial to the DF arise either from the skin
(e.g., sebaceous cyst) or subcutaneous (SC) tissues (e.g., dermoid cyst, hemorrhagic cyst, lymphatic cyst, lipoma, and neurobroma). Midline
cervical swellings are summarized, according to
their anatomical site, in Table9.1.
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9 Midline Cervical Swellings
189
Table 9.1 Midline cervical swellings according to anatomical location
Anatomical region Causes
Submental region Submental lymphadenopathy
Sublingual dermoid cyst
Hour-glass ranula
Abscess related to the
mandible (central incisors)
Hyoid bone region Thyroglossal cyst
Median ectopic thyroid tissue
Sub-hyoid bursitis
Tumor of the hyoid bone
Laryngeal/
pharyngeal region
Tracheal region Pre-tracheal lymphadenopathy
Supra-sternal space
(space of burns)
Pre-laryngeal (Delphian)
lymphadenopathy
Laryngeal tumors.
Bursa in front of Adam’s apple
Chondritis of thyroid cartilage
Retro-pharyngeal abscess
Laryngocele
Nodule in the isthmus of the
thyroid gland
Cyst in the isthmus of the
thyroid gland
Lymphadenopathy
Lipoma
Teratoma
Thymoma
Aneurysm of the aorta or
innominate artery
High aortic arch
9.4 Cervical Dermoid Cyst
lesion resulting from entrapped ectodermal tissue
of the rst and second branchial arches [8], which
fuse in-utero during the third and fourth weeks
[9–11]. Such cysts may lie above (supra-hyoid)
or below (infra-hyoid) the mylohyoid muscle
[12]. Other authors suggest that congenital cysts
may be a variant of thyro-glossal duct cyst with
predominantly ectodermal components. Acquired
dermoid cysts may result from iatrogenic or traumatic implantation of epithelial cells [10].
9.4.3 Pathology
Histologically, midline cervical dermoid cysts
are divided into three types: (1) “epidermoid
cysts” lined with stratied squamous epithelium,
(2) “dermoid cysts” showing evidence of skin
appendages (e.g., hair follicles, hair, sweat, and
sebaceous glands), and (3) “teratomas” (teratoid
cysts) containing all three germinal layers (mesodermal elements), in addition to skin appendages
[13]. The latter is the rarest type [14, 15] and is
nearly always benign; in rare cases, squamous
cell carcinoma may develop from the wall of the
cyst in adults [16]. The contents of the dermoid
cyst are variably keratinous, caseous, sebaceous,
or purulent with hair, nails, fat globules, and cholesterol clefts [4].
9.4.1 Epidemiology
Dermoid cysts of the head and neck represent upto
6.9% of all body dermoid cysts [3, 4]. A cervical
dermoid cyst may present anywhere along the midline. It may present as a sub-lingual mass above or
below the mylohyoid muscle and may bulge into
the sub-mental triangle. The oor of the mouth is
the second most common site for the presentation
of dermoid cysts in the head and neck region, after
the peri-orbital region [5]; approximately, 23–34%
occurs in the oor of the mouth [6, 7].
9.4.2 Etiology/Pathogenesis
Dermoid cyst could be congenital (developmental) or acquired. Most researchers believe that a
congenital dermoid cyst is a dysembryogenetic
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9.4.4 Clinical Picture
It usually presents between 10 and 25years of age
[17], affecting both sexes equally [18]. The patient
complains of a midline slow-growing, painless,
cervical swelling, which becomes painful and tender if secondarily infected [19]. On examination,
the swelling is smooth, spherical, opaque, uctuant, and clearly dened [19, 20]. Its size varies
from 1.2 to 12cm when noticed [21, 22]. Cystic
lesions occurring superior to the mylohyoid muscle have the potential to displace the tongue toward
the palate resulting in difculty with mastication,
dysphagia, speech difculties, and airway obstruction [13]. For cystic lesions developing below the
mylohyoid musculature, a submental (or submandibular) swelling is observed. The reported major
complications associated with sub-lingual der-
190
M. Sakr
moid cysts include upper respiratory tract infection, anemia, respiratory obstruction, feeding
difculties, and esthetic challenges [8].
9.4.5 Investigations
Diagnostic imaging modalities include ultrasonography (US), CT scan, and MRI.On US, a dermoid cyst usually appears as a unilocular cystic
mass, which can be heterogenous depending on
the presence or absence of dermal appendages in
the cyst. Both, CT scan and MRI, provide excellent tissue characterization and precise anatomical localization with respect to the geniohyoid
and mylohyoid muscles [22, 23]. This would be
most valuable to the surgeon during excision of
the cyst [24, 25]. Recent advances in the management of sublingual dermoid cyst advocate the
inclusion of thyroid scintigraphy in the preoperative diagnosis of the cyst of the oor of the mouth,
to assess if thyroid gland is involved [26, 27].
9.4.7 Treatment
The only effective treatment option for a dermoid
cyst is complete surgical excision (enucleation)
[26, 27, 29, 30]. If it is sub-lingual in position, the
mucous membrane appears normal and the cyst
can be felt bidigitally. Surgical excision is preferable through the oral route as it gives a good view
of the cyst, an easy access, and satisfactory esthetic
results (hidden scar) [31] (Fig. 9.2). Large dermoid cysts (9–12cm) plunging in the sublingual
space have also been reported to be enucleated
successfully via the intra-oral approach [8, 22].
The extra-oral (cervical) approach is usually
used for very large sublingual dermoid cysts
“plunging” in the submental and/or submandibular
spaces, and in cases of infection that could compromise the patient’s airways [4, 32]. In such cases,
careful dissection is needed during surgery to avoid
injury of the hypoglossal nerve. In exceptionally
huge cysts, a combined intra-oral and extra-oral
approach may be necessary to provide direct visualization of important adjacent structures [20, 33].
9.4.6 Dierential Diagnosis
9.4.8 Prognosis
The differentials of a dermoid cyst can be largely
grouped into three categories; infections/inammations, neoplasms, and cystic lesions [13, 28].
Histologically, the contents of a dermoid cyst
often contain keratin, sebaceous glands, hairs,
nails, fat globules, and even cartilages [25]. These
characteristic features settle the diagnosis of a
dermoid cyst.
a b
Fig. 9.2 (a) Sub-lingual dermoid cyst presenting as an intra-oral swelling. (b) The cyst being excised through an intra-
oral route
Prognosis of sublingual dermoid cysts is generally good. With complete excision, recurrence is
very rare because the brous capsule around the
cyst facilitates its enucleation [20, 34]. A 5% rate
of “malignant transformation” of the oral dermoid cysts into the teratoid type has been
reported [29, 30].
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9 Midline Cervical Swellings
191
9.5 Abscess inRelation
toOdontogenic Infections
9.5.1 Etiology/Pathophysiology
When odontogenic infections from the lower central and lateral incisors progress to the labial aspect
of the alveolar processes of the mandible and
break through the bone under the attachment of the
mentalis muscle, they usually appear as an abscess
or stula on the skin in the chin area. Plain X-ray
appearance is diagnostic, showing a central area of
destruction around the root of the tooth with bone
rarefaction surrounded by sclerosis.
Occasionally, odontogenic infections can
spread out into the submental space and form an
abscess [35]. The swelling occurs around the chin
and in the submental triangle. Contributing factors
may include poor dental hygiene, tooth extractions, and trauma (e.g., fractures of the mandible
and lacerations of the oor of the mouth).
9.5.2 Diagnosis
In general, diagnosis is made by a complete medical history and physical examination. The abscess
is painful and tender, and the overlying skin is red
and hot. Culture from the pus is recommended, primarily to identify Methicillin- resistant
Staphylococcus aureus (MRSA). In addition, diagnostic procedures for a neck abscess may include
(1) throat culture; taking a swab of the back of the
throat to determine the type of organism causing
the infection, (2) blood tests including complete
blood count (CBC), erythrocyte sedimentation rate
(ESR), C-reactive protein (CRP) to measure the
body’s response to infection, (3) US to determine
consistency of the mass (cystic or solid), and (4)
CT scan, it shows detailed images of the mass and
its relations to surrounding structures.
ment of a submental abscess is incision and
drainage (I&D), preferably under general anesthesia, plus appropriate antibiotics. Some small
abscesses resolve without draining. Warm compresses help accelerate the process. I&D are indicated when signicant pain, tenderness, and
swelling are present; it is unnecessary to wait for
uctuance.
9.6 Sub-hyoid Bursitis
9.6.1 Location
Sub-hyoid bursa lies between the posterior surface of the body of the hyoid bone and the thyrohyoid membrane (also known as retro-hyoid
bursa) [36–39] (Fig.9.3).
9.6.2 Etiology/Pathophysiology
When bursitis occurs, the bursa enlarges with
uid, and any movement against or direct pressure upon the bursa will precipitate pain for the
patient. There are many causes of bursitis, including overuse injury, infectious disease, trauma, and
inammatory disorders [40, 41]. Traumatic bursitis puts the patient at risk for “septic” bursitis,
which is most often caused by direct penetration
of the bursa through the skin, often by invasive
procedures. Septic bursitis through hematogenous
spread is rare due to the relatively poor blood sup-
9.5.3 Treatment
Specic treatment is usually based on extent of
the condition, and the patient’s age, overall
health, and medical history. In general, the treat-
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Fig. 9.3 Location of sub-hyoid bursa between the hyoid
bone and the thyro-hyoid membrane
192
M. Sakr
ply of the bursa Staphylococcus aureus causes the
majority of septic bursitis. Another important
cause of bursitis is autoimmune conditions and
systemic inammatory conditions. Lastly, bursitis
can be idiopathic in origin [40, 41].
The bursa itself is a synovial lining that represents a potential space, insofar as it is collapsed
upon itself until a resulting trigger causes the
bursa to become irritated and ll with synovial
uid resulting in the formation of a swelling. The
patient experiences pain when the inamed bursa
is then compressed. However, not all bursitis is
associated with an overt inammatory process.
9.6.3 Clinical Picture
Sub-hyoid bursitis is encountered equally in both
sexes and usually affects old people. In general,
immuno-compromised patients are at increased
risk of developing septic bursitis.
Clinically, there are two forms of bursitis such
as acute and chronic. Acute bursitis typically results
from trauma or infection, while chronic bursitis is
more likely the result of inammatory arthropathies and repetitive pressure/overuse, or “microtraumas.” In acute bursitis, patients generally
present with pain on palpation of the bursa. The
bursa itself has had time to expand to accommodate
the increased uid resulting in a signicant swelling and thickening of the bursa. The skin should be
evaluated for trauma, erythema, and warmth.
The swelling in chronic sub-hyoid bursitis is
usually painless, non-tender, and occurs at the
lower border of the hyoid bone, in front of the
thyro-hyoid membrane. It is characteristically
sausage-shaped with its long axis “transverse”
and mobile with deglutition and with protrusion
of the tongue. It is usually translucent but
becomes turbid when infected.
9.6.4 Diagnosis
Diagnosis can be made clinically and without
further studies; however, imaging plays a role in
the diagnosis and management of bursitis. On
US, the bursa is seen as a uid-lled anechoic
structure lined by a hyper-echoic wall. Color
Doppler can show signs of infection, such as
hyperemia of the bursa and the surrounding tissues [41]. Aspiration of the inamed bursa can be
helpful in the diagnosis of septic bursitis.
Aspirated uid should be sent for cell count,
gram stain, and culture. A white blood cell count
of <500/mm3 from the aspirated uid is consistent with noninfectious bursitis [42–44].
Sub-hyoid bursitis should be differentiated
from midline neck swellings, particularly those
that move with deglutition including mainly
thyro-glossal cyst, median ectopic thyroid tissue,
laryngocele, and enlarged LNs.
9.6.5 Management
The vast majority of bursitis will heal on its own.
Conservative treatment for symptomatic improvement involves the use of anti- inammatory drugs
and oral antibiotics (in septic bursitis). Local
injections of corticosteroid are not recommended
as it carries an increased risk of iatrogenic septic
bursitis, skin atrophy, or draining sinus tracts [44].
In bursitis caused by systemic inammatory conditions, it is important that the physician treats the
underlying condition. Finally, for certain cases,
the bursa can be excised surgically.
9.6.6 Prognosis
Bursitis is not a fatal disorder and most patients
have a good outcome. The vast majority are managed as outpatients. However, patients who do
not avoid the trigger tend to develop recurrences
[45, 46].
9.7 Median Actopic Thyroid
Tissue
9.7.1 Denitions
“Ectopic thyroid tissue” is dened as “thyroid tissue not located antero-laterally to the 2nd and 4th
tracheal cartilages” [47]. When thyroid tissue is
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9 Midline Cervical Swellings
193
present in an ectopic location along with a eutopic
thyroid, it is referred to as “accessory thyroid”
[48]. “True ectopic thyroid” is when thyroid tissue is absent in the normal location, which makes
diagnosis rather easy; however, accessory thyroid
tissue in addition to normal thyroid gland can
make diagnosis difcult.
9.7.2 Embryogenesis/Etiology
Normally, at 7 weeks of gestation, the thyroid
gland assumes its normal anatomical position in
the neck below the larynx and hyoid bone, anterolateral to the second, third, and fourth tracheal
cartilaginous rings [49, 50]. Disturbances during
embryogenesis such as partial descent or excessive migration can lead to an abnormal development of the gland resulting in anomalous
locations of the thyroid tissue.
Ectopic thyroid tissue in the midline of the
neck may also occur as a result of postsurgical
seeding. It was reported that this tissue becomes
hypertrophic under the inuence of increased
thyroid stimulating hormone (TSH) in thyroidectomized patients [51, 52].
9.7.3 Location/Classication
Ectopic thyroid can be divided anatomically into
two types (1) “lingual” type (90%), which is
found between the circumvallate papillae and
epiglottis, along the midline of the tongue base,
and (2) “sub-lingual” type (10%), which is found
along the course of the thyro-glossal duct cyst at
either supra- or infra-hyoid locations, outside the
tongue parenchyma, located between the geniohyoid and mylohyoid muscles [48, 53, 54].
9.7.4 Clinical Presentation
swelling, the patient may be asymptomatic or
present with symptoms such as dysphagia, dyspnea, and choking sensation, depending on the
size, location, and associated endocrine dysfunction of the ectopic glands [56]. Approximately,
70% of patients present with hypothyroidism,
probably due to disrupted vascular supply secondary to abnormal migration of the thyroid [57].
The ectopic thyroid tissue is susceptible to the
same disorders that may affect a normal thyroid
gland, including simple and toxic goiters,
Hashimoto’s thyroiditis (HT), benign adenomas,
and malignancies [58]. The incidence of carcinoma in ectopic thyroid is reported to be approximately 1% [59, 60]. Follicular carcinoma is the
most common subtype in ectopic thyroid, instead
of the more common papillary subtype [61]. In
case of malignancy, resection of other thyroid tissue should be considered to help with treatment,
staging, and monitoring of metastases and disease recurrence [62].
9.7.5 Pathology
9.7.5.1 Macroscopic Appearance
The average size of a manifested lesion of ectopic
thyroid tissue is 2–4cm (range, 0.2–7.3cm). It is
often encapsulated and can be cystic. Cut surface
resembles normal thyroid parenchyma (brownish
red) [63].
9.7.5.2 Microscopic (Histological)
Features
The microscopic features of ectopic thyroid tissue
may show (1) the same histological appearance as
the orthotopic thyroid tissue, composed of colloid-lled follicles, (2) signs of hyperplasia or
thyroiditis, and (3) cytological or histological features of thyroid carcinoma (should be considered
as metastases until proven otherwise) [64, 65].
Ectopic thyroid can manifest clinically in any age
group, occurring more commonly in females
especially during increased physiological demand
of thyroid hormones such as puberty, pregnancy,
and menopause [55]. Apart from the cervical
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9.7.6 Work-Up
The algorithm proposed by Prado in 2012 advises
US imaging early during the diagnostic work-up
for a suspected ectopic thyroid. US scan should
194
Fig. 9.4 Scintigraphy with Technetium 99m (99mTc)
pertechnetate showing uptake of the ectopic thyroid tissue
(arrow) in a euthyroid patient
follow clinical palpation for the orthotopic thyroid gland but precede CT scan or MRI, FNAB,
and thyroid function testing [49]. Doppler imaging increases sensitivity in detecting ectopic thyroid tissue [48, 66].
Scintigraphy with technetium-99m (99mTc)
remains the gold standard for ectopic thyroid
diagnosis, not only conrming the location and
extension of the ectopic thyroid and the presence
or absence of the orthotropic thyroid but can also
provide information about the shape and overall
activity of the thyroid, which is often unobtainable with other imaging modalities (Fig.9.4) [59,
67]. If ectopic thyroid or neoplasia is suspected,
particularly in the presence of an orthotopic thyroid gland, FNA is suggested because it can identify thyroid tissue with a 95–97% accuracy rate
and is reliable in excluding malignancy [55].
M. Sakr
lipomas, epidermoid cysts, and neoplasm. Since
ectopic thyroid is solid in consistency, thyroglossal duct cyst and branchial cyst are easily
excluded. The presence of vascular ow and
absence of hyper-echoic hilum in the ectopic thyroid nodule help to exclude the possibility of
lipomas, epidermoid cysts, and lymphadenopathy [47, 49, 50].
9.7.8 Treatment
Treatment of ectopic thyroid depends on size,
symptomology, complications, thyroid functions,
and suspected malignancy [68]. If the patient is
asymptomatic or minimally symptomatic, observation is recommended. Bulk reduction with thyroxin replacement therapy is suggested for
hypothyroid patients with lingual thyroid and
those having symptoms attributable to mass
effect caused by compensatory gland hypertrophy [69].
Surgical intervention is reserved for patients
having ectopic sub-lingual thyroids or lingual
thyroids, which are refractory to bulk reduction
with thyroxin replacement therapy, or in symptomatic patients having dyspnea, dysphagia,
hemorrhagic or cystic degeneration, or suspicious for malignancy [54, 55, 68, 70, 71]. Since
70–90% of patients with ectopic thyroid tissue do
not have a normal thyroid gland [55] and the
ectopic thyroid is the only thyroid tissue present
[71], it must be kept in mind that when surgical
excision is considered, these patients are at risk
of developing permanent hypothyroidism postoperatively [72]. Auto-transplantation has
recently (2020) been performed to restore a
euthyroid state [73].
9.8 Tuberculous Thyroid
Chondritis
9.7.7 Dierential Diagnosis
The differential diagnosis of a midline ectopic
thyroid tissue should include thyro-glossal duct
cysts, midline branchial cysts, lymphadenopathy,
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9.8.1 Epidemiology
Extra-pulmonary tuberculosis (TB) in the Head
and Neck region most frequently occurs in the
cervical LNs (>90%), followed by the larynx
(2–6%) [74, 75]. Involvement of the temporal
9 Midline Cervical Swellings
195
bone, sino-nasal cavity, eye, pharynx, thyroid
gland, and skull base is even less frequently
involved [74–76].
Laryngeal TB (LTB) is the most common
granulomatous disease of the larynx. Today, it
occurs in only 1% of cases [74–77]. It might be
localized in the larynx as a primary lesion without pulmonary involvement [78], which makes
its diagnosis rather difcult [79] as it more
closely resembles a laryngeal carcinoma than any
other laryngeal illness [80–83]. In the past, LTB
typically affected young people, with advanced
pulmonary TB, in the second or third decade of
life. However, today it involves mainly people in
their 50s or 60s [84].
9.8.2 Clinical Presentation
The larynx becomes infected either by direct
spread from the lungs or by hematogenous spread
from other sites [80, 83, 85], with no evidence of
pulmonary disease [75, 82, 86]. Currently,
patients with LTB primarily present with hoarseness of voice (80–90%), odynophagia (50–67%),
and to a lesser extent dysphagia, dyspnea, stridor,
cough and hemoptysis [84]. In a physical examination, the true vocal cords are most frequently
affected by LTB [76, 82, 85]. Laryngeal TB can
manifest as edema, hyperemia, or ulcerative
lesions in the larynx and can also present as a
nodule, an exophytic mass, or diffuse obliteration
of an anatomical structure [85]. Systemic symptoms have become rare [76, 80–83, 87].
9.8.3 Diagnosis/Dierential
Diagnosis
tate many other diseases. However, characteristic
CT scan ndings of LTB include bilateral
involvement, thickening of the free margin of the
epiglottis, good preservation of the pre-epiglottic
and para-laryngeal fat spaces, as well as the primary integrity of the laryngeal structure. Thus,
cartilage destruction is not usually seen on CT
scans in LTB [89].
Histopathology settles the diagnosis of LTB
by demonstrating epitheloid cell granulomas
with chronic inammatory cells and caseous
necrosis, without features of malignancy [84].
Ziehl-Neelsen staining of the tissue biopsies and
sputum will reveal acid-fast bacilli.
Laryngeal carcinoma is the main differential
diagnosis of LTB.Other differentials include sarcoidosis, cat-scratch disease, syphilis, leprosy,
lethal midline granuloma, Wegener’s granulomatosis, fungal infections, and chronic nonspecic
laryngitis [74, 90].
9.8.4 Treatment
The primary treatment of LTB is by standard
antituberculous therapy for 6months. It includes
isoniazid 300 mg/day, rifampicin 600 mg/day,
pyrizinamide 1500 mg/day, and ethambutol
1400 mg/day. Improvement of dysphagia and
resolution of cavernous lung lesions are expected
to occur within several weeks [81, 85, 91]. Monga
etal. (2016) reported that, in their case, the tuberculous swelling disappeared in 2 weeks, and
hoarseness in 2months [92]. If not treated early,
LTB can result in sub-glottic stenosis, muscular
involvement, and vocal cord paralysis when the
crico-arytenoid joint or RLN is involved [80, 85].
Diagnostic studies include histopathological tissue examinations with Ziehl–Neelsen staining
for acid-fast bacilli, and identication of M.
tuberculosis by polymerase chain reaction (PCR)
or bacterial culture. The latter method, although
time-consuming, is considered the reference
standard [88].
Similar to chest X-ray, CT scan of the neck
cannot denitively identify LTB since it can imi-
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9.9 Thyroglossal Cyst
9.9.1 Embryology andPathogenesis
The thyroid gland buds off the foregut diverticulum at the base of the tongue in the region of the
future foramen cecum at 3weeks of embryonic
life. As the fetal neck develops, the thyroid tissue
becomes more anterior and caudal until it rests in
196
M. Sakr
its normal position. The “descent” of the thyroid
is intimately connected with the development of
the hyoid bone. Residual thyroglossal duct system left behind in the migration may persist and
subsequently present in the midline of the neck as
a thyroglossal duct cyst. Rarely, midline ectopic
thyroid tissue masquerades as a thyroglossal duct
cyst and may represent the patient’s only thyroid
tissue [1, 93, 94].
9.9.2 Incidence
Remnants of thyroglossal duct are estimated to
persist in 7% of the population. Cystic remnants
are the commonest congenital anomaly of the
neck. It is three times more common than the
branchial cysts [1, 95]. The lesion is most commonly appreciated in the 2- to 4-year-old child
when the baby fat disappears. Some authors state
that the incidence is higher in females and some
deny any sex predilection [1, 2]. Approximately,
90% of cases occur in the midline and 10% are
lateral, of which 95% are left and 5% are right.
9.9.3 Sites
9.9.5 Clinical Picture
The cyst is painless and presents for a long time.
Pain, tenderness, and an increase in size occur
only if the cyst becomes infected, usually after
upper respiratory tract infection. On examination, it is 0.5–5cm large, well-dened, round in
shape, and with a smooth surface (Fig.9.5).
The thyroglossal cyst moves vertically up with
protrusion of the tongue (characteristic sign), or
swallowing. The lower jaw is held still with the
mouth opened. The clinician holds the cyst
between nger and thumb and feels it tugged
upwards when the tongue protrudes. It is a difcult sign to elicit so one should not expect much
movement. This sign is due to the cyst being
abnormally attached to the hyoid bone by a
brous tissue remnant, and the hyoid bone being
normally attached to the tongue through the hyoglossus muscle (Figs. 9.6 and 9.7). Although
diagnostic, its absence does not exclude the diagnosis. This sign is absent from most of the cysts
which are below the thyroid cartilage (which are
indeed rare).
The brous tissue track allows the cyst to be
moved sideways, but not up and down. Some
cysts may form on both sides of the hyoid bone
A thyroglossal cyst may present in the substance
of the tongue (lingual thyroglossal cyst), in the
supra-hyoid region (as a mass in the oor of the
mouth or sub-mental triangle) or in the infrahyoid region, which is the commonest site, as the
duct obliterates from above downwards. This latter type might present in front of the thyroid cartilage, cricoid cartilage, or even at the
supra-sternal notch. Occasionally, it presents as
an intra-thyroidal mass. The commonest site of
all is the peri-hyoid bone cyst [2, 93, 95].
9.9.4 Pathology
The cyst is lined by cubical or stratied squamous epithelium. It contains mucoid uid or
cheesy yellowish material rich in cholesterol.
Sometimes, the wall may contain “ectopic thyroid tissue” [93].
t.me/Dr_Mouayyad_AlbtousH
Fig. 9.5 A large thyroglossal cyst in the midline of the
neck of a 19-year-old young gentleman
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