Most common cause of solitary thyroid nodule is: September 2008
Ans. B: Follicular adenoma Assessment of thyroid nodules History - Rapid painless growth suggests malignancy - Sudden painful growth suggests haemorrhage into degenerating colloid nodule - Family history - 20% medullary carcinomas are familial associated with MEN 2 Syndrome History of radiation exposure - Increased incidence of thyroid malignancy - usually papillary - Most occult ( Usually good prognosis Examination Follicular adenoma constitutes 30-40% of all solitary thyroid nodules, 80% solitary thyroid nodules occur in women. The risk of malignancy is increased three fold in men Malignancy more common in children and >60 years Assess whether true solitary or dominant nodule within goitre True solitary nodule have 10% risk of malignancy Dominant nodule in multinodular goitre has 2-5% risk of malignancy Evidence of fixation or nodal involvement suggests malignancy Most patients will be clinically and biochemically euthyroid Obstructive signs - stridor, tracheal detion, neck vein engorgement Hoarseness and vocal cord paralysis suggests recurrent laryngeal nerve palsy 50% solitary thyroid nodules in children are cancers 70% will have cervical and 15% pulmonary metastases on presentation Childhood tumours have good prognosis with greater than 80% 10 year survival Investigations Biochemical assessment - Thyroid functional status - Free T4 and TSH - Thyroid Antibodies - anti-thyroglobulin and anti-microsomal If positive family history an possibility of medullary carcinoma - calcitonin - If suspicion of MEN2 Syndrome will need 24 hr urinary catecholamine estimations to exclude phaeochromocytoma prior to surgery Standard radiography - Chest radiography and thoracic inlet views if obstructive symptoms Isotope scanning - 'I, 121or 99Tch scanning provides functional assessment of thyroid Nodules classified as cold, warm or hot Unable to differentiate benign and malignant nodules Most solitary thyroid nodules are cold Most cancers arise in cold nodules Risk of cancer in a cold nodule is 10-15% Risk of tumour in a hot nodule is negligible
Physiological goitre
Follicular adenoma
Colloid degenerations
Cysts