E03.4
BillableAtrophy of thyroid (acquired)
HCC Category Mapping
RxHCCHCC 44 — Thyroid and Parathyroid Disorders
0.000What This Code Means
A condition where the thyroid gland has shrunk or wasted away over time, leading to reduced thyroid hormone production and hypothyroidism.
Coding Tips
- •Verify this is acquired atrophy, not congenital; document the underlying cause if known (radiation, autoimmune, surgical)
- •This code indicates the structural change; ensure hypothyroidism symptoms are also documented for complete clinical picture
Clinical Significance
Atrophy of thyroid (acquired) represents the progressive shrinkage and loss of functional thyroid tissue, typically as the end result of chronic autoimmune thyroiditis (Hashimoto disease) where immune-mediated destruction leads to fibrotic replacement of the gland. It can also occur following radioactive iodine treatment, external beam radiation, or chronic thyroiditis. The condition results in permanent hypothyroidism requiring lifelong thyroid hormone replacement.
Documentation Requirements
- ✓Documentation should confirm acquired thyroid atrophy, ideally with imaging (thyroid ultrasound showing small, heterogeneous gland), thyroid function tests showing hypothyroidism, and the identified cause of atrophy.
- ✓History of autoimmune thyroiditis, prior radioactive iodine treatment, or radiation therapy should be noted.
- ✓Current levothyroxine replacement and monitoring should be documented.
Excludes 1 — Do NOT code together
- congenital atrophy of thyroid (E03.1)
Commonly Confused Codes
E06.3 (Autoimmune thyroiditis) may be the underlying cause but represents the active inflammatory phase.E03.9 (Hypothyroidism, unspecified) captures the functional consequence without the structural finding.E89.0 (Postprocedural hypothyroidism) is used specifically for hypothyroidism following thyroidectomy or other procedures.E03.1 (Congenital hypothyroidism without goiter) captures congenital absence or hypoplasia, not acquired atrophy.