Friday, October 29, 2010

Lingual thyroid and its management

Clinical details:

6 years old female patient came with complaints of:
1. Difficulty in swallowing - 6 months
2. Occasional episodes of bleeding from mouth - 2 months

On examination:

Oral cavity: Pinkish globular mass could be seen in the posterior 1/3 of tongue. The mass was firm on palpation. The posterior border of the mass was not visible on oral examination.
Both tonsils were found to be enlarged grade III.



















Radiology:

X ray soft tissue neck lateral view:

















X ray soft tissue neck lateral view showing mass in the suprahyoid region occupying posterior 1/3 of tongue.
Axial CT scan of neck showing mass involving the posterior 1/3 of tongue.


Contrast CT axial view showing absent thyroid gland in the neck
Ultrasound neck: Absent thyroid gland in the neck

Thyroid profile:

Pt was euthyroid with normal serum T3 T4 and TSH levels

Management:

Patient was taken up for surgery.
supra hyoid midline approach was preferred.
Skin crease incision is made just below the hyoid bone in the neck.
Skin flap elevated in the subplatysmal plane. Hyoid bone was exposed.
Supra hyoid muscles were resected from the superior border of hyoid bone
Mylohyoid muscle fibers are resected and retracted. Lingual thyroid mass removed in toto and the wound closed in layers.

Discussion:

Lingual thyroid is a rare embryonic aberration with an incidence rate of 1 in 100,000 individuals.
This condition is invariably due to failure of descent of thyroid gland. Parathyroid glands in these patients will
be found in the neck in their normal positions because of their separate origin embryologically.
Symptoms are invariably caused due to the mass effect of the lesion. It has also been pointed out that these
ectopic thyroid gland may not be in a position to cater to the increasing demands of thyroxine during menarche / pregnancy and
may undergo enlargement causing increasing symptoms. Incidence of malignancy is also more in ectopic thyroid glands hence
it is always better to resect the gland and place the patient under supplemental thyroid hormones.
Surgical approaches:
1. Removal via the oral cavity: This is the commonly practiced approach. This approach has the advantage of avoiding neck incisions.
The mouth of the patient is kept open by using Boyle's Davis mouth gag. Using either diathermy / laser / cobalator the dissection is
started from the anterior border of the mass and it is removed totally by encircling incision. Bleeders if any can be cauterized using
a bipolar cautery. This approach is advisable if the posterior border of the lesion is visible on opening the mouth.
2. Suprahyoid midline approach: This is another commonly used approach which has been described already. This lesion is useful
in patients with large lingual thyroid mass.
3. Lateral pharyngotomy approach: This approach is useful in removing big mass with a predominant vascular supply from the lingual
artery. This approach will also facilitate repositioning of ectopic thyroid mass in the neck.
4. Midline mandible and tongue splitting approach: Useful in adults with a huge lingual thyroid mass. The mandible is slit in the midline
by performing a midline osteotomy. The tongue is slit right in the middle till the foramen cecum portion is reached. The lingual
thyroid mass is removed in an encircling manner.




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