D37.3 ICD-10-CM Code: Neoplasm of uncertain behavior of appendix
HCC Buddy Code Card
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FY 2026 Apr update / Neoplasms (C00-D49) / Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes (D37-D48)
D37.3
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceNeoplasm of uncertain behavior of appendix
This code describes an abnormal growth in the appendix that cannot yet be determined to be either cancer or a benign (non-cancerous) tumor. It represents a condition requiring further investigation or monitoring to establish its true nature.
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
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Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for D37.3 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for D37.3 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for D37.3 in this effective period.
Excludes 1
Official- stromal tumors of uncertain behavior of digestive system (D48.1-)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for D37.3 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for D37.3 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for D37.3 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 D37.3 an HCC code?
No. D37.3 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
D37.3 is the ICD-10-CM diagnosis code for neoplasm of uncertain behavior of appendix. This code describes an abnormal growth in the appendix that cannot yet be determined to be either cancer or a benign (non-cancerous) tumor. It represents a condition requiring further investigation or monitoring to establish its true nature. D37.3 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes (d37-d48).
D37.3 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.
Use this code when pathology reports indicate uncertain or indeterminate behavior of appendiceal lesions, not when the tumor is definitively benign (D12.3) or malignant (C18.1).
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for D37.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code when pathology reports indicate uncertain or indeterminate behavior of appendiceal lesions, not when the tumor is definitively benign (D12.3) or malignant (C18.1)
- •Ensure documentation supports the uncertain nature of the neoplasm; if subsequent testing clarifies the diagnosis, update coding to the appropriate benign or malignant code