2026 ICD-10-CM Diagnosis Code D40.12Neoplasm of uncertain behavior of left testis
ICD-10-CM Codes›C00–D49›D37-D48›D40
- Billable — Valid for Submission
- Not Chronic
D40.12 is a billable ICD-10-CM diagnosis code for neoplasm of uncertain behavior of left testis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 715 through 716, 722 through 724. Coders also document this condition as bilateral neoplasm of uncertain behavior of testes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Neoplasms of unspecified nature or uncertain behavior.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Bilateral neoplasm of uncertain behavior of testes
- Neoplasm of uncertain behavior of left testis
- Neoplasm of uncertain behavior of right testis
- Neoplasm of uncertain behavior of testis
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
| Site | Malig. Primary | Malig. Secondary | Ca in situ | Benign | Uncertain | Unspec. |
|---|---|---|---|---|---|---|
| testis, testes | C62.9 | C79.82 | D07.69 | D29.2 | D40.1 | D49.59 |
| testis, testes › descended | C62.1 | C79.82 | D07.69 | D29.2 | D40.1 | D49.59 |
| testis, testes › ectopic | C62.0 | C79.82 | D07.69 | D29.2 | D40.1 | D49.59 |
| testis, testes › retained | C62.0 | C79.82 | D07.69 | D29.2 | D40.1 | D49.59 |
| testis, testes › scrotal | C62.1 | C79.82 | D07.69 | D29.2 | D40.1 | D49.59 |
| testis, testes › undescended | C62.0 | C79.82 | D07.69 | D29.2 | D40.1 | D49.59 |
| testis, testes › unspecified whether descended or undescended | C62.9 | C79.82 | D07.69 | D29.2 | D40.1 | D49.59 |
Patient EducationClinical
Testicular Cancer
Testicular cancer is a cancer that develops in the tissues of one or both testicles. The testicles, or testes, are part of the male reproductive system. They make male hormones and sperm. They are two egg-shaped glands inside the scrotum, a sac of loose skin that lies below the penis. You can get cancer in one or both testicles.
The full article covers:
- What is testicular cancer?
- Who is most likely to develop testicular cancer?
- What are the symptoms of testicular cancer?
- How is testicular cancer diagnosed?
- What are the treatments for testicular cancer?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert D40.12 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About D40.12Overview
Is D40.12 (Neoplasm of uncertain behavior of testis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report neoplasm of uncertain behavior of left testis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does D40.12 group to?
When neoplasm of uncertain behavior of left testis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 715, 716, 722, 723, 724, with relative weights from 0.6117 to 2.2373 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of D40.12?
Under the General Equivalence Mappings, neoplasm of uncertain behavior of left testis converts to ICD-9-CM 236.4 (unc behav neo testis). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
