E21.4 Other specified disorders of parathyroid gland

ICD-10-CM E21.4: Other specified disorders of parathyroid gland

ICD-10-CM code E21.4 represents other specified disorders of the parathyroid gland, functioning as an active diagnosis concept. It falls under the parent category E21, which covers hyperparathyroidism and other parathyroid gland disorders. This reference summarizes official terminology records and clinical literature regarding parathyroid gland disorders. 1 4

Plain-language overview

Code E21.4 is an active diagnosis concept in the ICD-10-CM terminology system, and its official preferred name is Other specified disorders of parathyroid gland. 1

What this code represents

The semantic type assigned to the E21.4 terminology record is Disease or Syndrome, and its official published abbreviation matches its preferred name. 1

Code E21.4 is a child concept of parent category E21, which broadly covers hyperparathyroidism and other disorders of the parathyroid gland in the ICD-10-CM hierarchy. 1

Coding details

The E21.4 terminology record indicates it has narrower child concepts, distinguishing it from the adjacent E21.5 code for unspecified parathyroid gland disorders. 1 4

Documentation considerations

Clinical literature notes that medical treatment options for parathyroid conditions should take into account plasma biochemistry, x-ray findings, and the dimensions of the largest parathyroid glands. 2

Clinical context

Clinical literature indicates that chronic stimulation of parathyroid secretory function involves progressive rises in serum PTH and parathyroid gland hyperplasia due to enhanced cell proliferation. 2

Studies showed that patients whose parathyroid glands had high oxyphil cell counts were likely to be relatively refractory to drug treatment, according to clinical literature. 2

Coverage and utilization context

A Medicare billing and coding article for parathyroid hormone includes lists of related endocrine diagnoses, such as primary hyperparathyroidism and unspecified hypoparathyroidism. 5 6

What the sources add

While the official terminology record defines the structural hierarchy of E21.4, the clinical literature source provides operational context regarding the biological mechanisms of parathyroid gland hyperplasia and treatment resistance. 1 2

Sources

1. ICD-10-CM E21.4 terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. Bookshelf — ncbi.nlm.nih.gov; accessed 2026-07-27.
3. ICD-10 | Primary hyperparathyroidism (E21.0) — cdek.pharmacy.purdue.edu; accessed 2026-07-27.
4. ICD-10 Version:2019 — icd.who.int; accessed 2026-07-27.
5. Article - Billing and Coding: Parathormone (Parathyroid Hormone) (A57122) — cms.gov; accessed 2026-07-27.
6. Article - Billing and Coding: Parathormone (Parathyroid Hormone) (A57122) — cms.gov; accessed 2026-07-27.