D21.3 ICD-10-CM Code: Benign neoplasm of connective and other soft tissue of thorax
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Neoplasms (C00-D49) / Benign neoplasms, except benign neuroendocrine tumors (D10-D36)
D21.3
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceBenign neoplasm of connective and other soft tissue of thorax
A benign (non-cancerous) tumor that develops in the soft tissues of the chest, such as fat, muscle, or connective tissue. These tumors are not life-threatening but may require monitoring or removal if they cause symptoms or functional problems.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
Basket needed
Code Book Path
Inclusion Terms
Official- Benign neoplasm of axilla
- Benign neoplasm of diaphragm
- Benign neoplasm of great vessels
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for D21.3 in this effective period.
Related Child Codes
Includes
Official- benign neoplasm of blood vessel
- benign neoplasm of bursa
- benign neoplasm of cartilage
- benign neoplasm of fascia
- benign neoplasm of fat
Excludes 1
Official- benign neoplasm of heart (D15.1)
- benign neoplasm of mediastinum (D15.2)
- benign neoplasm of thymus (D15.0)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for D21.3 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for D21.3 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for D21.3 in this effective period.
Buddy Documentation Tip
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is D21.3 an HCC code?
No. D21.3 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
D21.3 is the ICD-10-CM diagnosis code for benign neoplasm of connective and other soft tissue of thorax. A benign (non-cancerous) tumor that develops in the soft tissues of the chest, such as fat, muscle, or connective tissue. These tumors are not life-threatening but may require monitoring or removal if they cause symptoms or functional problems. D21.3 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering benign neoplasms, except benign neuroendocrine tumors (d10-d36).
D21.3 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Verify the anatomical location is specifically in the thorax (chest wall, mediastinum, or pleura) rather than other body regions, as this affects code selection.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for D21.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the anatomical location is specifically in the thorax (chest wall, mediastinum, or pleura) rather than other body regions, as this affects code selection
- •Confirm the neoplasm is benign; if malignant or of uncertain behavior, use different D-codes or C-codes accordingly