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【文摘发布】先天性颈部囊肿，窦道和瘘管——
Stephanie P. Acierno, MD, MPH,
John H.T. Waldhausen, MD*
Department of Surgery, Children’s Hospital and Regional Medical Center,
University of Washington School of Medicine, G0035,
4800 Sand Point Way, NE, Seattle, WA 98105, USA
Thyroglossal duct anomalies
Thyroglossal duct anomalies are the second most common pediatric neckmass, behind adenopathy in frequency [1]. Thyroglossal duct remnantsoccur in approximately 7% of the population, although only a minority of these is ever symptomatic [1].
Embryology
The thyroid gland forms from a diverticulum (median thyroid anlage) located
between the anterior and posterior muscle complexes of the tongue at
week 3 of gestation. As the embryo grows, the diverticulum is displaced caudally
into the neck and fuses with components from the fourth and fifth branchial pouches (lateral thyroid anlagen). The descent continues anterior
to or through the hyoid bone with the median anlage elongating into the
thyroglossal duct (Fig. 1) [2]. By weeks 5 to 8 of gestation, the thyroglossal
duct obliterates, leaving a proximal remnant, the foramen cecum, at the base
of the tongue and a distal remnant, the pyramidal lobe of the thyroid [1,2]. If
the duct fails to obliterate before the formation of the mesodermal anlage of
the hyoid bone, it persists as a cyst [2].
Clinical presentation and diagnosis
Two thirds of thyroglossal duct anomalies are diagnosed within the first
3 decades of life, with more than half being identified before age 10 years
[1]. The most common presentation is that of a painless cystic neck mass
near the hyoid bone in the midline (Figs. 2 and 3) [2]. Although they are
most commonly found immediately adjacent to the hyoid (66%), they can
also be located between the tongue and hyoid, between the hyoid and pyramidal
lobe, within the tongue, or within the thyroid [2,3]. The mass usually
moves with swallowing or protrusion of the tongue. Approximately one
third present with a concurrent or prior infection, which is the more common
presentation in adults [2,4]. One fourth of patients present with a draining
sinus that results from spontaneous drainage or surgical drainage of an
abscess [2]. This drainage can result in a foul taste in the mouth if the spontaneous
drainage occurred by way of the foramen cecum. These lesions also
fluctuate in size. Other rare presentations can be severe respiratory distress
or sudden infant death syndrome from lesions at the base of the tongue,
a lateral cystic neck mass, an anterior tongue fistula, or coexistence with
branchial anomalies [2].
The preoperative evaluation for a patient who has a suspected thyroglossal
duct cyst includes a complete history and physical examination, preoperative
ultrasound, and a screening thyroid stimulating hormone (TSH) level.
Patients who have history, examination findings, or elevated TSH levels suggesting
hypothyroidism or a solid mass should undergo scintiscanning to
rule out a median ectopic thyroid [2]. When median ectopic thyroid is present,
all of the patient’s functional thyroid tissue can be located within the
cyst, and its removal would render the patient permanently dependent on
thyroid replacement. The management of median ectopic thyroid is controversial.
Some investigators believe these patients can be treated with exogenous
thyroid hormone to suppress the gland, whereas others advocate for
resection for reasons that are discussed later [2]. Although median ectopic
thyroid only occurs in 1% to 2% of thyroglossal duct cysts, some authors advocate for scintiscans in all patients [5].
Treatment
Elective surgical excision is the treatment of choice for uncomplicated
thyroglossal duct cysts to prevent infection of the cyst. The Sistrunk procedure is performed, rather than simple excision, to reduce recurrence
risk [2]. With the patient in supine position and the neck extended, a transverse
incision is made over the mass. The dissection is carried down to the
cyst, then caudally to identify the tract to the pyramidal lobe. If present,
it is excised en bloc with the cyst. The surgeon then dissects cranially toward
the hyoid bone and a block of tissue around the proximal tract is also excised.
The central portion of the hyoid bone is also excised and the tract
is further dissected with a core of tissue from the muscle at the base of
the tongue to the foramen cecum (Fig. 4) [2]. After confirming adequate
proximal dissection by pressure on the base of the tongue from the mouth,
the tract is ligated and transected. Intrathyroidal thyroglossal duct cysts
should also undergo a Sistrunk procedure if there is a transhyoidal fistulous
tract, but can be treated with hemi-thyroidectomy if no tract can be
identified [3].
Infected cysts or sinuses are first managed by relieving the infection. The cysts are usually infected by way of the mouth, thus the most common organisms
are Haemophilus influenza, Staphylococcus aureus, and Staphylococcus
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作者:admin@医学,生命科学 2011-02-15 05:12
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