case of the week : thyroglossal cyst
DESCRIPTION
A presentation about an interesting case that came to the Radiology Department of Sebha Medical Center. A 17 years old male, presented with a painful neck swelling, The swelling was first noticed 10 years ago and was small and painless then. In the last two months, the swelling increased in size and became painful and started to cause slight discomfort on swallowing. The presentation contains 50 slides, and is divided into the following parts : 1 - The case 2 - Thyroglossal cysts 3 - Imaging Thyroglossal cysts 4 - Differential diagnoses This presentation was prepared by me and I will present it today in sha Allah in the tutorials of the Radiology Department of Sebha Medical Center.TRANSCRIPT
Case presentation :
Thyroglossal cyst
Dr.Abdalla Mutwakil Gamal
Radiology Deparment
Sebha Medical Center
Content
• The case
• Thyroglossal cysts
• Imaging Thyroglossal cysts
• Differential diagnosis
THE CASE
History
• 17 years old male, presented with a painful neck swelling. The swelling was
painless and small in size when it was first noticed when the patient was 7
years old. In the last two months the swelling increased in size and started
to become painful and to cause slight discomfort on swallowing.
• OSR : Increased fatiguability. No heat or cold intolerance. No change in
bowel or sleep habits. No increased irritability. No palpitation.
• PH : anaemia that needed transfusion of 2 units of blood when the patient
was 7 years old.
• FH : Mother has hyperthyroidism for the last 16 years and is on
carbimazole.
General Examination
• GE :
– NAD
– PR = 92 bpm
Local Examination
Single swelling in front of the neck at the midline, oval in shape, about 3x4 cm
in shape, overlying skin is red and shiny but shows no scars, sinuses or
ulcers. The swelling moves with deglutition but not with tongue protrusion !
On palpation, the swelling is warm and tender. Soft in consistency with +ve
fluctuation. No palpable cervical lymph node enlargement.
Investigations
• CBC = Not available
• TFT
– T3 = 1.0 ng/ml (Normal = 0.6 – 1.85)
– T4 = 8.7 µg/dL (Normal = 4.8 – 12)
– TSH = 0.8 (Normal = 0.3–3.0 µIU/mL)
• Others
– RBS = 77 mg/dL
– Urea = 15 mg/dL
Ultrasound
Evidance of complicated cyst in the subcutenous tissue in the midline
of the neck with thick fluid inside measuring about 3x4 cm
CT Scan
Differential diagnosis
• Midline neck lump :
– Submental lymph nodes
– Thyroglossal cyst
– Thyroid swelling
– Dermoid cyst
THYROGLOSSAL CYSTS
Definition
• A thyroglossal cyst is
a fibrous cyst that
forms from a
persistent
thyroglossal duct.
Embryology
• 4th week of gestation :
proliferation
• 7th week, complete
descend
• Duct disappearance
Epidemiology
• They typically present during childhood
(90% before the age of 10), or remain
asymptomatic until they become infected,
in which case they can present at any
time.
• Thyroglossal duct cysts account for 70%
of all congenital neck anomalies, and are
the second most common benign neck
mass, after lymphadenopathy.
Presentation
• The following are the most common symptoms of a
thyroglossal duct cyst. However, each child may
experience symptoms differently. Symptoms may
include:
• A small, soft, round mass in the center front of the neck
• Tenderness, redness, and swelling of the mass, if
infected
• A small opening in the skin near the mass, with drainage
of mucus from the cyst
• Difficulty swallowing or breathing
Complications
• Cyst infection (follows Upper Respiratory Infection)
• Papillary carcinoma (in adults)
Treatment
• Infected thyroglossal cyst
– Majority respond to antibiotics.
– Surgical drainage if abscess formed or failure
to respond to antibiotics.
– Elective excision of the cyst once acute
infection has resolved.
• Surgery
– Excision is recommended for most cysts.
IMAGING THYROGLOSSAL CYSTS
Imaging options
• Ultrasonography
• Computed Tomography
• Magnetic Resonance Imaging
Ultrasonography
• Unless infected, they are painless, fluctuant masses
which spread the strap muscles. The fluid is usually
anechoic and the walls are thin, without internal
vascularity.
• However, in some cases, the internal fluid may contain
debris. This is particularly the case in the adult patient
where the cysts may be complex heterogeneous
masses.
• If there is associated infection, there may be surrounding
inflammatory change.
• Ultrasound image demonstrates a
midline infrahyoid unilocular mass
with a homogeneously hypoechoic
internal echotexture, typical of a
TDC.
• O/E - Left paramedian swelling.
• Cystic swelling at level of hyoid
bone. Flow is seen in septa.
• Well-defined lesion is noted at
level of hyoid and infrainfrahyoid
level. It is in mid line and
predominently in right paramedian
location.
• It is mainly cystic lesion with few
septa / echoes. NO calcification is
noted.
• It is deep to platysma.
• It is superficial to strap muscles.
• Vascularity is noted in wall and in
solid parts.
• A well-defined cystic lesion with
internal echoes and debris is
noted in mid line. Lower border of
the lesion abutts hyoid bone.
Lesion shows wall thickening and
vascularity.
• No perilesional hypervascularity is
noted.
• Location and ultrasound features
favour thyroglossal duct cyst.
Infected thyroglossal duct cyst
longitudinal
Thyroglossal duct cyst with a
vascularized wall
Infected thick walled thyroglossal
duct cyst
Thyroglossal duct cyst with a
vascularized wall
Computed Tomography
• At CT, thyroglossal duct cysts are thin walled, smooth, well defined
homogeneously attenuating lesions with an anterior midline or para-midline
location. The generally accepted rule is that they should be within 2 cms of
the midline. The may demonstrate slight rim (capsular) enhancement.
• Sternocleidomastoid is typically displaced posteriorly or posterolaterally and
in some cases, they may be embedded in the infrahyoid strap muscles.
• Computed tomography has a high degree of diagnostic accuracy for
thyroglossal duct cysts (TDC). The most helpful features in the differential
diagnosis are the midline location, most often at or below the hyoid bone,
and the intimate relationship of infrahyoid TDCs to the strap muscles. CT
better evaluates the potential for thyroglossal duct carcinoma and is thus
preferred in adult patients.
• Axial contrast-enhanced CT
shows a large cystic lesion at the
level of the thyroid cartilage,
slightly to the right of midline,
embedded in the right strap
muscles, consistent with a TDC.
• Sagittal CT image in a 76-year-old
man with a rapidly enlarging neck
mass shows a large infrahyoid
cystic lesion representing
pathologically proven thyroglossal
duct cyst carcinoma
• Thyroglossal duct cyst .
Reconstructed CT scan of the
neck demonstrates a midline
cystic lesion with a slightly
enhancing wall. The contents
measured fluid density.
• Thyroglossal duct cyst in a 41-
year-old man Axial contrast-
enhanced CT scans show a cystic
mass in the anterior midline of the
• 25 years old male cyst.
• Axial :: CT w/contrast (IV)
Thyroglossal Duct Cyst Midline
cystic structure
Magnetic Resonance Imaging
• T1: variable
– low signal: if low protein / uncomplicated
– high signal (most common 6) due to
• previous haemorrhage / infection
• high protein (probably due to previous complication)
• T2 - typically high signal
• T1 C+ (Gd)
– no enhancement in uncomplicated cysts
– thin peripheral enhancement may be seen
• Axial T1-weighted image obtained
following intravenous gadolinium
administration demonstrates
peripheral rim enhancement of the
thyroglossal duct cyst.
• A sagittal T1-weighted
postcontrast image in the same
patient as in the previous image
nicely depicts the midline
thyroglossal duct cyst and its
location relative to the airway,
tongue base, hyoid bone, and
strap muscles.
DIFFERENTIAL DIAGNOSIS
Differential diagnosis
• Midline neck lump :
– Submental lymph nodes
– Thyroglossal cyst
– Thyroid swelling
– Dermoid cyst
Submental lymph nodes
• Drainage Pattern
– Lower lip
– Floor of Mouth
– Tip of Tongue
– Skin of Cheek
Thyroid swelling
• A 12-year-old patient with an
asymptomatic, palpable thyroid
nodule, which was noticed
upon routine physical
examination.
• Roughly 5% of thyroid nodules
are malignant; the remainder
represent a variety of benign
diagnoses, including colloid
nodules, degenerative cysts,
hyperplasia, thyroiditis, or
benign neoplasms.
Dermoid cysts
• A dermoid cyst is a pocket or
cavity under the skin that
contains tissues normally
present in the outer layers of
the skin. The pocket forms a
mass that is sometimes visible
at birth or in early infancy but
often is not seen until later
years. Dermoid cysts are
usually found on the head or
neck and face, but can occur
anywhere on the body.