2026 ICD-10-CM Diagnosis Code N42.31Prostatic intraepithelial neoplasia

ICD-10-CM Codes›N00–N99›N40-N53›N42

ICD-10-CM N42.31
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

N42.31 is a billable ICD-10-CM diagnosis code for prostatic intraepithelial neoplasia. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 729 through 730. Coders also document this condition as low grade prostatic intraepithelial neoplasia. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified male genital disorders.

Code Identity

ICD-10-CM Code
N42.31
Billable Status
Yes — Valid for Submission
Code Describes
Prostatic intraepithelial neoplasia
Short Description
Prostatic intraepithelial neoplasia
Same as the full description in the CMS dataset.
Parent Code
N42.3
Dysplasia of prostate

Code Classification

ChapterN00–N99Diseases of the genitourinary system
SectionN40-N53Diseases of male genital organs
CategoryN42Other and unspecified disorders of prostate
This CodeN42.31Prostatic intraepithelial neoplasia

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Low grade prostatic intraepithelial neoplasia
  • Prostatic intraepithelial neoplasia

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • PIN
  • Prostatic intraepithelial neoplasia I (PIN I)
  • Prostatic intraepithelial neoplasia II (PIN II)

Type 1 Excludes

  • prostatic intraepithelial neoplasia III PIN III D07.5

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Neoplasia
      • intraepithelial (histologically confirmed)
        • prostate (histologically confirmed) (PIN)
    • Neoplasia
      • intraepithelial (histologically confirmed)
        • prostate (histologically confirmed) (PIN)
          • grade I
    • Neoplasia
      • intraepithelial (histologically confirmed)
        • prostate (histologically confirmed) (PIN)
          • grade II

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR GEN016
Other specified male genital disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Prostatic Intraepithelial Neoplasia

    a premalignant change arising in the prostatic epithelium, regarded as the most important and most likely precursor of prostatic adenocarcinoma. the neoplasia takes the form of an intra-acinar or ductal proliferation of secretory cells with unequivocal nuclear anaplasia, which corresponds to nuclear grade 2 and 3 invasive prostate cancer.

Patient EducationClinical

Prostate Diseases

The prostate is a gland in the male reproductive system. It lies just below the bladder. It makes fluid that is part of semen.

The full article covers:

  • What is the prostate?
  • What are prostate diseases?
  • Who is more likely to develop prostate diseases?
  • What are the symptoms of prostate diseases?
  • How are prostate diseases diagnosed?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert N42.31 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
602.3 Dysplasia of prostate
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement N42.31 replaces the following previously assigned code(s):

  • N42.3 - Dysplasia of prostate
FY 2018AddedAdded to the ICD-10-CM code setEffective October 1, 2017.
FY 2019–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About N42.31Overview

Is N42.31 (Dysplasia of prostate) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report prostatic intraepithelial neoplasia on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does N42.31 group to?

When prostatic intraepithelial neoplasia is the principal diagnosis on an inpatient stay, it groups to MS-DRG 729, 730, with relative weights from 0.6720 to 1.0587 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of N42.31?

Under the General Equivalence Mappings, prostatic intraepithelial neoplasia converts to ICD-9-CM 602.3 (dysplasia of prostate). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.