General Surgery for NEET-PG
Thyroid Swellings for NEET-PG
Thyroid swellings, or goitres, are common surgical presentations that require distinguishing benign from malignant disease and assessing thyroid function. For NEET-PG, the high-yield material is the classification of goitre, the role of fine needle aspiration cytology, the types of thyroid carcinoma, and the complications of thyroidectomy. A thyroid swelling moves upward on swallowing because of its attachment to the pretracheal fascia, and a thyroglossal cyst additionally moves on tongue protrusion. Goitres are classified as diffuse, multinodular, or solitary nodular, and function may be euthyroid, hyperthyroid, or hypothyroid. Investigation combines thyroid function tests, ultrasound, and fine needle aspiration cytology, which is the single most useful investigation for a thyroid nodule, though it cannot distinguish follicular adenoma from follicular carcinoma because that requires capsular or vascular invasion on histology. Papillary carcinoma is the most common thyroid cancer, spreads through lymphatics, and has an excellent prognosis, with Orphan Annie eye nuclei and psammoma bodies as histological clues. Follicular carcinoma spreads haematogenously, medullary carcinoma arises from parafollicular C cells and secretes calcitonin, and anaplastic carcinoma is aggressive in the elderly. Thyroidectomy risks include recurrent laryngeal nerve injury causing hoarseness, hypoparathyroidism causing hypocalcaemia, and thyroid storm. Knowing the FNAC role, papillary features, and postoperative complications are recurrent exam anchors.
MedNext Academy | 3 min read
Thyroid Swellings for NEET-PG
Thyroid swellings, or goitres, are common surgical presentations that require distinguishing benign from malignant disease and assessing thyroid function. For NEET-PG, the high-yield material is the classification of goitre, the role of fine needle aspiration cytology, the types of thyroid carcinoma, and the complications of thyroidectomy. A thyroid swelling moves upward on swallowing because of its attachment to the pretracheal fascia, and a thyroglossal cyst additionally moves on tongue protrusion. Goitres are classified as diffuse, multinodular, or solitary nodular, and function may be euthyroid, hyperthyroid, or hypothyroid. Investigation combines thyroid function tests, ultrasound, and fine needle aspiration cytology, which is the single most useful investigation for a thyroid nodule, though it cannot distinguish follicular adenoma from follicular carcinoma because that requires capsular or vascular invasion on histology. Papillary carcinoma is the most common thyroid cancer, spreads through lymphatics, and has an excellent prognosis, with Orphan Annie eye nuclei and psammoma bodies as histological clues. Follicular carcinoma spreads haematogenously, medullary carcinoma arises from parafollicular C cells and secretes calcitonin, and anaplastic carcinoma is aggressive in the elderly. Thyroidectomy risks include recurrent laryngeal nerve injury causing hoarseness, hypoparathyroidism causing hypocalcaemia, and thyroid storm. Knowing the FNAC role, papillary features, and postoperative complications are recurrent exam anchors.
Thyroid swellings, or goitres, are common surgical presentations that require distinguishing benign from malignant disease and assessing thyroid function. For NEET-PG, the high-yield material is the classification of goitre, the role of fine needle aspiration cytology, the types of thyroid carcinoma, and the complications of thyroidectomy. A thyroid swelling moves upward on swallowing because of its attachment to the pretracheal fascia, and a thyroglossal cyst additionally moves on tongue protrusion. Goitres are classified as diffuse, multinodular, or solitary nodular, and function may be euthyroid, hyperthyroid, or hypothyroid. Investigation combines thyroid function tests, ultrasound, and fine needle aspiration cytology, which is the single most useful investigation for a thyroid nodule, though it cannot distinguish follicular adenoma from follicular carcinoma because that requires capsular or vascular invasion on histology. Papillary carcinoma is the most common thyroid cancer, spreads through lymphatics, and has an excellent prognosis, with Orphan Annie eye nuclei and psammoma bodies as histological clues. Follicular carcinoma spreads haematogenously, medullary carcinoma arises from parafollicular C cells and secretes calcitonin, and anaplastic carcinoma is aggressive in the elderly. Thyroidectomy risks include recurrent laryngeal nerve injury causing hoarseness, hypoparathyroidism causing hypocalcaemia, and thyroid storm. Knowing the FNAC role, papillary features, and postoperative complications are recurrent exam anchors.
Key points
- **Movement on swallowing:** A thyroid swelling moves up on swallowing due to attachment to the pretracheal fascia. A thyroglossal cyst also moves on tongue protrusion.
- **Goitre types:** Classified as diffuse, multinodular, or solitary nodular. Function may be euthyroid, hyperthyroid, or hypothyroid.
- **FNAC role:** Fine needle aspiration cytology is the single most useful investigation for a thyroid nodule to distinguish benign from malignant.
- **FNAC limitation:** FNAC cannot separate follicular adenoma from follicular carcinoma, since that needs capsular or vascular invasion seen only on histology.
- **Papillary carcinoma:** Most common thyroid cancer, spreads via lymphatics, excellent prognosis. Shows Orphan Annie eye nuclei and psammoma bodies.
- **Follicular carcinoma:** Spreads haematogenously to bone and lung. Diagnosis rests on capsular and vascular invasion, not cytology alone.
- **Medullary carcinoma:** Arises from parafollicular C cells, secretes calcitonin, and can be part of multiple endocrine neoplasia type 2.
- **Anaplastic carcinoma:** Highly aggressive, occurs in the elderly, presents as a rapidly enlarging hard mass with a very poor prognosis.
- **Recurrent laryngeal injury:** Injury during thyroidectomy causes hoarseness. Bilateral injury can cause airway obstruction needing urgent airway management.
- **Hypocalcaemia:** Inadvertent removal or devascularisation of parathyroid glands causes hypocalcaemia with perioral tingling and tetany.
- **Thyroid storm:** A life-threatening crisis of severe hyperthyroidism that may follow surgery in an inadequately prepared patient.
Frequently Asked Questions
Why does a thyroid swelling move on swallowing?
The thyroid is attached to the pretracheal fascia and larynx, so it moves upward with the trachea during swallowing.
What is the most useful investigation for a thyroid nodule?
Fine needle aspiration cytology is the single most useful investigation to differentiate benign from malignant thyroid nodules.
Why can't FNAC diagnose follicular carcinoma?
Follicular carcinoma is diagnosed by capsular or vascular invasion seen on histology, which cytology cannot demonstrate, so it looks identical to follicular adenoma on FNAC.
Which is the most common thyroid cancer?
Papillary carcinoma is the most common thyroid cancer. It spreads through lymphatics and carries an excellent prognosis.
What are the main complications of thyroidectomy?
Key complications are recurrent laryngeal nerve injury causing hoarseness, hypoparathyroidism causing hypocalcaemia, and thyroid storm.
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