D47.09 Other mast cell neoplasms of uncertain behavior

The ICD-10-CM code for Other mast cell neoplasms of uncertain behavior is D47.09 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

2: Neoplasms (C00-D49)

Section

D37-D48: Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes (D37-D48)

Category D47

14 codes (11 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to D47.09:

• Mastocytosis
• Mastocytoma (extracutaneous)
• Mast cell › tumor
• Neoplasm, neoplastic › mast cell, of uncertain behavior NEC
• Tumor › mast cell
• Mast cell › neoplasm › of uncertain behavior NEC

Inclusion Terms

• Extracutaneous mastocytoma
• Mast cell tumor NOS
• Mastocytoma NOS
• Mastocytosis NOS

U.S. Hospital Utilization

• An estimated 635 U.S. inpatient stays in 2023 included D47.09 among the documented diagnoses.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

Tx of primary site (TOC entry)

a. Admission/Encounter for treatment of primary site ............................................................. 33

Tx of secondary site (TOC entry)

b. Admission/Encounter for treatment of secondary site .......................................................... 33

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)