Fig. 25.3 Thyroid images in patients with palpable solitary nodules in their thyroid glands. You will note that the appearances of the scans are similar, each showing an area of deficient or reduced uptake while the rest of the gland shows a homogeneous normal uptake. It is not possible to distinguish between the causes of a solitary nodule: (a) a haemorrhage, (b) a cyst, (c) a follicular thyroid cancer. Ultrasound should be combined with thyroid imaging to demonstrate the simple cyst for aspiration cytology, and to enable fine-needle biopsy for the echogenic (solid) nodule, which is non-functional in a thyroid scan. If the mass in the gland is solitary and solid, about 12 per cent of these cases prove to be malignant.
