Can you explain in lay terms that I have a 1.6 cm left adrenal adenoma, a normal low‑dose dexamethasone suppression test (LD DST), and an A1c of 6.5% indicating type 2 diabetes mellitus (T2DM), and what the implications are?

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Understanding Your Left Adrenal Nodule and Test Results

You have a benign (non-cancerous) growth on your left adrenal gland that is not producing excess hormones, and you also have diabetes that needs treatment.

What the Adrenal Nodule Means

Your imaging showed a 1.6 cm nodule on your left adrenal gland that looks like an adenoma—a benign, non-cancerous growth 1. This size falls into a low-risk category, as studies show that in people without a history of cancer, malignant lesions are extremely rare below 3-5 cm, with only a 1.5% rate of cancer overall in incidental adrenal masses 1.

Why the Dexamethasone Test Was Done

Even though you don't have obvious symptoms of hormone excess, doctors routinely check whether these nodules are secretly producing cortisol (a stress hormone) 1, 2. This is important because:

  • 12-23% of people with incidental adrenal nodules have some degree of hormone overproduction, even without obvious symptoms 1
  • Excess cortisol can cause high blood pressure, diabetes, weight gain, and bone loss—problems that might be mistaken for other conditions 1, 2

What Your Normal Dexamethasone Test Means

Your normal dexamethasone suppression test is excellent news—it means your adrenal nodule is NOT producing excess cortisol 2.

In this test, you took a dexamethasone pill (a synthetic steroid) at night, and your body properly "turned off" its cortisol production the next morning 2. If the nodule were making too much cortisol, your body wouldn't have been able to suppress it 2, 3.

This result tells us:

  • The nodule is truly "non-functioning"—just sitting there doing nothing harmful 3
  • You don't have Cushing's syndrome (a condition of cortisol excess) 2, 3
  • The nodule is very likely to remain stable and benign 1

What This Means for Your Diabetes (A1c 6.5%)

Your hemoglobin A1c of 6.5% confirms you have type 2 diabetes 4. This is a separate issue from your adrenal nodule.

The good news is that your normal dexamethasone test rules out cortisol excess as a cause of your diabetes 4. If you had been making too much cortisol, it would have been causing or worsening your diabetes by making your body resistant to insulin 4. Since your test was normal, your diabetes is standard type 2 diabetes that needs typical diabetes management.

What Happens Next

For the Adrenal Nodule:

  • No surgery or treatment is needed because the nodule is small, benign-appearing, and not making excess hormones 1
  • Your doctor may recommend repeat imaging in 6-12 months to confirm the nodule stays stable 1
  • If it grows larger than 4 cm or starts producing hormones in the future, further evaluation would be needed 1

For Your Diabetes:

  • You need standard diabetes treatment with lifestyle changes (diet, exercise) and likely medication 4
  • Your diabetes is not being caused by your adrenal gland, so treating the diabetes won't affect the nodule and vice versa 4

Important Reassurance

The combination of a small adrenal nodule with normal hormone testing is very common and carries an excellent prognosis 1. These nodules are found in 4-6% of people who get CT scans for other reasons, and the vast majority remain stable and never cause problems 1. Your normal dexamethasone test essentially confirms this is one of those harmless findings that just needs occasional monitoring.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Diagnosis and Management of Cushing Syndrome

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Diabetes and adrenal disease.

Bailliere's clinical endocrinology and metabolism, 1992

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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