GOITRE, simple solitary nodule and toxic solitary nodule
The term goitre is derived from latin word gutter- that means throat and describes generalised enlargement of thyroid gland.
I. Simple Goitre
– Diffuse Hyperplastic (Physiological)
- Simple Solitary nodule (Adenoma)
- Simple Multinodular Goitre
II. Toxic Goitre
• Diffuse Toxic Goitre (Graves’ disease)
• Multinodular with secondary toxicity
• Toxic adenoma
• Autoimmune – Hashimoto’s thyroiditis
• Granulomatous – de Quervein’s thyroiditis
• Fibrosing – Reidel’s thyroiditis
• Infective – Acute (bacterial, viral, subacute thyroiditis)
- Chronic (tuberculous, syphilitic)
V. Others – Amyloid goitre
Any single focal lesion in the thyroid gland
DD for solitary nodule
1. Follicular adenoma (Simple adenoma thyroid)
2. Carcinoma (Papillary Ca, Follicular Ca)
3. Colloid goiter
4 Toxic nodule
5. Thyroiditis – Hashimoto’s thyroiditis
6 Any solitary Cyst
3 – 4% of population
Swelling in thyroid region
Symptoms of hyperthyroidism may or may not be present
Non toxic or simple solitary nodule (Adenoma of thyroid)
Thyroid adenomas are common, solitary nodules in the thyroid.
They can occur at any age, but usually young individuals.
Females out number males by a ratio of 3 or 4 : 1.
Simple adenomas (Non toxic) appear as Solitary nodules
Grossly, the tumor may be 1 to 10 centimeters in size.
It is soft and fleshy and may have cystic areas.
It is almost always encapsulated and solitary.
The majority of benign tumours of the thyroid gland arise from the follicular epithelium and so, are follicular adenomas.
Clinically, adenomas may:
• cause pressure symptoms in the neck
• suddenly enlarge and become painful due to intralesional haemorrhages
• cause hyperthyroidism – but unassociated with the ophthalmopathy seen in Grave’s disease, take up radioactive iodine – appear as “hot” nodules, and named as toxic solitary nodule.
Stimulation of thyroid gland
- TSH is not the only factor which stimulates thyroid follicular cell proliferation.
- There are other growth factors, including immunoglobulins exert an influence over the thyroid.
- The heterogenous structural and functional response in the thyroid resulting in characteristic nodularity may be due to the presence of clone of cells particularly sensitive to growth stimulation.
Predisposing factors of goitre
Daily requirement is 0.1 to 0.15 mg. Deficient in mountain areas like Himalayan belt
Calcium is also goitrogenic
Often there is a family history suggesting genetic defect
Cabbage,kale and rape which contain thiocyanate
Para amino salicylic acid and antithyroid drugs
Natural history of goitre :
• Persistant growth stimulation leads to diffuse hyperplasia, wherein all lobules are composed of active follicles and Iodine uptake is uniform.
• This is a diffuse hyperplastic goitre which may persist for a long time, but is reversible if simulation stops.
• Later as a result of fluctuating stimulation, a mixed pattern develops with areas of active lobules and areas of inactive lobules.
• Active lobules become more vascular and hyperlastic until haemorrhage occurs causing central necrosis and leaving only a surrounding rind of active follicles.
• Necrotic lobules coalesce to form nodules filled either with Iodine free colloid or a mass of new inactive follicles.
• Continual repetition of this process results in nodular goitre.
The nodules are inactive in the multinodular goiter, but the internodular tissue is active.
The adenoma represents a initial response to TSH but often either become or are to begin with autonomous.
Initially, the amount of thyroid hormone secreted by the adenoma may be insufficient to cause metabolic disturbance.
However, as the adenoma grows larger and if it remains functional, the patient may exhibit signs of hyperthyroidism.
In such cases, do to feedback inhibition of TSH synthesis, the remainder of the thyroid may become atrophic.,
Clinical features of Solitary nodule
• Age – In younger individuals – Nodule is more likely to become malignant
• Sex – Less frequent in males
But if occurs – is more likely to be malignant
• Duration of nodule-
Present for long time – may be a benign condition..
Note progress of nodule, pain, obstructive symptoms
Sudden appearance – Carcinoma
Rapid enlargement – Haemorrhage into nodule -Carcinoma
Painful – Haemorrhage into nodule Carcinoma
- Hashimoto’s thyroiditis
Rule out toxic features – Chest pain
• Solitary swelling in thyroid
• Moves up with deglutition
• Margins well defined
• Consistency – usually firm
• Transverse Mobility restricted
• Enlarged lymph nodes may be present
Hard in consistency, enlarged lymph nodes, fixity –Carcinoma
Toxic solitary nodule
May be a part of generalized nodularity or true toxic adenoma. It is Autonomous.
Autonomous Toxic nodule: ↑ T3 & ↑T4
Surrounding normal thyroid tissue suppressed and inactive and become atrophied.
1. FNAC “ Investigation of choice”
By F.N.A.C. we can differentiate
Malignant / Benign cystic lesions
Differentiation between follicular adenoma and follicular carcinoma is not possible in FNAC
2. X’ray neck To rule out tracheal deviation and calcification
3. Xray chest To rule out retrostrenal involvement and lung secondaries in case of carcinoma
4. ULTRASONOGRAM: Solid or cystic swelling
5. THYROID Profile: Serum T3, T4, TSH
6. AUTOANTIBODY TITRE: If ↑ – it indicates autoimmune thyroiditis.
TREATMENT OF SOLITARY NODULE
• Follicular adenoma Hemithyroidectomy
• Carcinoma Near total Thyroidectomy
• Toxic nodule Hemithyroidectomy / Radioactive iodine
• Hashimoto’s thyroiditis Thyroxine, Steroid therapy, Surgery
• Reidel’s thyroiditis Thyroxine, Isthmusectomy
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