C96.29 Other malignant mast cell neoplasm

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from C96 Other and unspecified malignant neoplasms of lymphoid, hematopoietic and related tissue

Excludes1 (never code together)

• personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues (Z85.79)

Applies from C96.2 Malignant mast cell neoplasm

Excludes1 (never code together)

• indolent mastocytosis (D47.02)
• mast cell leukemia (C94.30)
• mastocytosis (congenital) (cutaneous) (Q82.2)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 21 — Lymphoma and Other Cancers
• CMS-HCC V22: HCC 10 — Lymphoma and Other Cancers
• RxHCC V08: HCC 21 — Lymphomas and Other Hematologic Cancers
• ESRD V24: HCC 10

MS-DRG index

Defines the logic of DRG(s) 011-013 in MDC PRE.

Approximate ICD-9-CM (GEMs)

• 202.60 Malignant mast cell tumors, unspecified site, extranodal and solid organ sites (approximate)
• 202.61 Malignant mast cell tumors, lymph nodes of head, face, and neck (approximate)
• 202.62 Malignant mast cell tumors, intrathoracic lymph nodes (approximate)
• 202.63 Malignant mast cell tumors, intra-abdominal lymph nodes (approximate)
• 202.64 Malignant mast cell tumors, lymph nodes of axilla and upper limb (approximate)
• 202.65 Malignant mast cell tumors, lymph nodes of inguinal region and lower limb (approximate)

Code annotations containing back-references to C96.29

Back-references to C96.29

• Type 1 Excludes: D89.4 Mast cell activation syndrome and related disorders ("malignant mastocytoma (C96.29)")

Back-references to C96.2

• Type 1 Excludes: D47.0 Mast cell neoplasms of uncertain behavior ("malignant mast cell neoplasm (C96.2-)")
• Type 1 Excludes: D89.4 Mast cell activation syndrome and related disorders ("malignant mast cell neoplasm (C96.2-)")
• Code First: N16 Renal tubulo-interstitial disorders in diseases classified elsewhere ("lymphoma (C81.0-C85.9, C96.0-C96.9)")
• Type 1 Excludes: Q82.2 Congenital cutaneous mastocytosis ("malignant mastocytosis (C96.2-)")

Back-references to C96

• Type 1 Excludes: C76 Malignant neoplasm of other and ill-defined sites ("malignant neoplasm of lymphoid, hematopoietic and related tissue (C81-C96)")
• Type 1 Excludes: C77 Secondary and unspecified malignant neoplasm of lymph nodes ("malignant neoplasm of lymph nodes, specified as primary (C81-C86, C88, C96.-)")
• Code Also: D59.39 Other hemolytic-uremic syndrome ("malignant neoplasm (C00-C96)")
• Code First: D84.81 Immunodeficiency due to conditions classified elsewhere ("malignant neoplasms (C00-C96)")
• Code First: E08 Diabetes mellitus due to underlying condition ("malignant neoplasm (C00-C96)")
• Code First: Z15.0 Genetic susceptibility to malignant neoplasm (", if applicable, any current malignant neoplasm (C00-C75, C81-C96)")

Diagnosis Index entries for C96.29

• Mast cell › neoplasm › malignant › specified type NEC
• Mastocytoma (extracutaneous) › malignant
• Mastocytosis › malignant
• Neoplasm, neoplastic › malignant mast cell › specified type NEC

Nearby codes

• C96.0 Multifocal and multisystemic (disseminated) Langerhans-cell histiocytosis
• C96.2 Malignant mast cell neoplasm
• C96.20 Malignant mast cell neoplasm, unspecified
• C96.21 Aggressive systemic mastocytosis
• C96.22 Mast cell sarcoma
• C96.29 Other malignant mast cell neoplasm (this code)
• C96.4 Sarcoma of dendritic cells (accessory cells)
• C96.5 Multifocal and unisystemic Langerhans-cell histiocytosis
• C96.6 Unifocal Langerhans-cell histiocytosis
• C96.A Histiocytic sarcoma
• C96.Z Other specified malignant neoplasms of lymphoid, hematopoietic and related tissue