E31.21 – Multiple endocrine neoplasia [MEN] type I

ICD-10-CM 2027 diagnosis code · Disorders of other endocrine glands

Billable code

ICD-10-CM code E31.21

Code: E31.21 (claims format: E3121)
Description: Multiple endocrine neoplasia [MEN] type I
Billable: Yes – valid for HIPAA-covered transactions
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 4. Endocrine, nutritional and metabolic diseases (E00-E89)
Block: E20-E35 Disorders of other endocrine glands
Parent codes: E31 › E31.2

Notes for E31.21

Applicable to:

Wermer's syndrome

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

E31 – Polyglandular dysfunction

Excludes1 (not coded here):

ataxia telangiectasia [Louis-Bar] (G11.3)
dystrophia myotonica [Steinert] (G71.11)
pseudohypoparathyroidism (E20.1)

E31.2 – Multiple endocrine neoplasia [MEN] syndromes

Applicable to:

Multiple endocrine adenomatosis

Code also:

any associated malignancies and other conditions associated with the syndromes

Block E20-E35

Excludes1 (not coded here):

galactorrhea (N64.3)
gynecomastia (N62)

Index terms for E31.21

Entries in the ICD-10-CM alphabetic index that lead to this code:

Related codes in E31.2

Frequently asked questions

What is ICD-10 code E31.21?

E31.21 is the ICD-10-CM code for multiple endocrine neoplasia [MEN] type I, in the block E20-E35 (Disorders of other endocrine glands).

Is E31.21 a billable code?

Yes. E31.21 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does E31.21 belong to?

It belongs to category E31 – Polyglandular dysfunction.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.