A nodule is a small, localized lump of cells. One specific type is the adenomatoid nodule, a noncancerous growth that develops in the thyroid gland. The thyroid is a butterfly-shaped gland at the base of the neck responsible for producing hormones that regulate metabolism. These nodules are part of a condition group known as nodular thyroid disease.
Characteristics of an Adenomatoid Nodule
The term “adenomatoid” is used because the growth’s appearance under a microscope resembles a gland-like structure. Specifically, these nodules are composed of follicular cells, which are the normal cells responsible for producing thyroid hormones. When examined by a pathologist, the nodule shows an increased number of these cells forming enlarged follicles.
These growths are distinct from another benign tumor, the follicular adenoma, due to the absence of a complete, thin tissue layer called a capsule surrounding them. An adenomatoid nodule blends into the surrounding thyroid tissue rather than being a completely separate and encapsulated growth. The presence of these nodules is frequent, and they are often compared to a common mole on the skin, but located internally. Most are asymptomatic and do not cause any health issues.
Detection and Diagnostic Process
Adenomatoid nodules are frequently discovered by chance during medical imaging like a CT or MRI scan of the neck for unrelated reasons. A nodule may also be found during a routine physical examination when a doctor feels the neck area. Once a lump is suspected, the diagnostic process begins to confirm its nature and rule out other conditions.
The initial evaluation includes blood tests to measure the level of thyroid-stimulating hormone (TSH). These tests help determine if the thyroid gland is functioning properly. Following blood work, a thyroid ultrasound is performed. This imaging test uses sound waves to create pictures of the thyroid, revealing the nodule’s size, shape, and whether it is solid or filled with fluid, but it cannot definitively determine if a nodule is benign.
To obtain a definitive diagnosis, a procedure called fine-needle aspiration (FNA) is often performed. During an FNA, a very thin needle is inserted into the nodule, often guided by ultrasound, to withdraw a small sample of cells. This sample is then sent to a laboratory where a pathologist examines the cells under a microscope to confirm that they are benign. FNA is a safe and highly accurate method for evaluating thyroid nodules.
Management and Monitoring
Once an adenomatoid nodule is confirmed to be benign and is not causing any symptoms, the most common approach is active surveillance. This strategy, sometimes called “watchful waiting,” involves no immediate treatment. Instead, the nodule is monitored over time to ensure it does not undergo significant changes. Follow-up appointments include repeat thyroid ultrasounds every 12 to 24 months to check for growth or changes.
Treatment is not required unless the nodule grows large enough to cause problems. If a nodule becomes so large that it presses on the windpipe or esophagus, it can lead to compressive symptoms like difficulty breathing or swallowing. In other instances, a large nodule might become a cosmetic concern. In these scenarios, surgical removal of the part of the thyroid containing the nodule might be recommended.