Toxic Adenoma and Multinodular Goiter with Case

00:01 Let's go on to another case.

00:03 A 55 year old woman was diagnosed with hyperthyroidism one week ago.

00:07 She also has a palpable right thyroid nodule which was found on clinical exam.

00:12 Her TSH was low and her free T4 was elevated.

00:17 She has no weight loss, no history of prior malignancy nor family history of any cancer.

00:23 What is the best next step in managing this patient? So clinically based on the information that we have, she has been diagnosed with hyperthyroidism and she also has a palpable right thyroid nodule.

00:37 This points to the diagnosis of a toxic adenoma.

00:41 The next step in the management would be thyroid scintigraphy scan or radioactive iodine uptake which in this case would show a single area of increased uptake of iodine in the area of the toxic adenoma.

00:58 Thyroid scintigraphy scanning is a nuclear medicine procedure that produces a visual display of functional thyroid tissue based on the selective uptake of radioactive iodine nucleides by the thyroid tissue.

01:13 If you look at this image, you see areas on the gray background of intense uptake which are much, much darker representing large black dots.

01:22 These represent toxic adenomas within the thyroid gland and are very discreet.

01:30 Activating mutations in the TSH receptor gene stimulate the production of thyroid hormone in a toxic nodule, usually referred to as an adenoma.

01:40 or in multiple hyperfunctioning nodules in a toxic multinodular goiter.

01:46 On exam, the nodule may be palpable or diffusely enlarged where it's called a goiter or it may have a nodular contour.

01:55 There is a very low risk of autonomous nodules from malignant transformation.

02:01 Usually in the range of less than 1%.

02:04 The diagnosis is usually made by thyroid scintigraphy.

02:07 In the case of an autonomous toxic nodule, this is described as "hot" or very dark on imaging.

02:17 You should always correlate any nodules found on scintigraphy scanning with an associated ultrasound.

02:23 Any additional nodules that are found on ultrasound that are not seen on scintigraphy scanning may require further investigation by doing a fine needle aspiration.

02:35 Radioactive iodine ablation emits gamma and beta radiation.

02:40 The camera detecting this on a nuclear testing will detect the uptake of the thyroid hormone and generate a picture for diagnosis.

02:51 Indications for surgery in patients with toxic adenomas include very large goiters with compression symptoms on the underlying tissue where there is concern for malignancy.

03:02 TSH secreting pituitary adenomas are extremely rare.

03:06 These are causes of secondary or central hyperthyroidism.

03:10 Serum TSH is detectable or normal with elevated T4 and/or T3 levels.

03:17 A pituitary MRI in these cases will usually demonstrate an adenoma.

03:21 The treatment for these conditions is removal of the pituitary tumor as thyroid-targeted therapy is invariably ineffective.