2026 ICD-10-CM Diagnosis Code D16.21Benign neoplasm of long bones of right lower limb
ICD-10-CM Codes›C00–D49›D10-D36›D16
- Billable — Valid for Submission
- Not Chronic
D16.21 is a billable ICD-10-CM diagnosis code for benign neoplasm of long bones of right lower limb. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 564 through 566. Coders also document this condition as benign neoplasm of bone of right lower limb. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Benign neoplasms.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Benign neoplasm of bone of right lower limb
- Benign neoplasm of long bone of right lower limb
- Bilateral enostosis of femurs
- Enostosis of femur
- Enostosis of fibula
- Enostosis of right fibula
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. |
|---|---|---|---|---|---|---|
| bone (periosteum) › femur (any part) | C40.2 | C79.51 | – | D16.2 | – | – |
| bone (periosteum) › fibula (any part) | C40.2 | C79.51 | – | D16.2 | – | – |
| bone (periosteum) › knee | C40.2 | C79.51 | – | D16.2 | – | – |
| bone (periosteum) › leg NEC | C40.2 | C79.51 | – | D16.2 | – | – |
| bone (periosteum) › limb NEC › lower (long bones) | C40.2 | C79.51 | – | D16.2 | – | – |
| cartilage (articular) (joint) NEC [See Also: Neoplasm, bone] › semilunar (knee) | C40.2 | C79.51 | – | D16.2 | D48.0 | D49.2 |
| femur (any part) | C40.2 | C79.5 | – | D16.2 | – | – |
| fibula (any part) | C40.2 | C79.51 | – | D16.2 | – | – |
| meniscus, knee joint (lateral) (medial) | C40.2 | C79.51 | – | D16.2 | D48.0 | D49.2 |
| semilunar cartilage (knee) | C40.2 | C79.51 | – | D16.2 | D48.0 | D49.2 |
| tibia (any part) | C40.2 | C79.51 | – | D16.2 | – | – |
Patient EducationClinical
Benign Tumors
Tumors are abnormal growths in your body. They can be either benign or malignant. Benign tumors aren't cancer. Malignant ones are. Benign tumors grow only in one place. They cannot spread or invade other parts of your body. Even so, they can be dangerous if they press on vital organs, such as your brain.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert D16.21 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About D16.21Overview
Is D16.21 (Benign neoplasm of long bones of lower limb) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report benign neoplasm of long bones of right lower limb on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does D16.21 group to?
When benign neoplasm of long bones of right lower limb is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 565, 566, with relative weights from 0.7493 to 1.5436 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of D16.21?
Under the General Equivalence Mappings, benign neoplasm of long bones of right lower limb converts to ICD-9-CM 213.7 (ben neo long bones leg). 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.
