MS-DRG 55 – Nervous System Neoplasms without MCC
A Medical DRG in MDC 01 (Diseases & Disorders of the Nervous System). Inpatient cases group to DRG 55 when the ICD-10-CM principal diagnosis is one of the 61 codes listed below and no secondary diagnosis on the MCC list is present. Its FY 2026 relative weight is 1.0196 with a geometric mean length of stay of 2.9 days.
Severity family
The grouper first assigns the case to MDC 01 from the principal diagnosis and finds no qualifying operating-room procedure (this is a Medical DRG; ICD-10-PCS codes do not drive assignment here), then applies the severity split from secondary diagnoses: with MCC → 54; without MCC → 55.
Principal Diagnosis Codes 61 codes · 12 categories
C70 Malignant neoplasm of meninges3 codes
C71 Malignant neoplasm of brain10 codes
- C71.0 Malignant neoplasm of cerebrum, except lobes and ventricles
- C71.1 Malignant neoplasm of frontal lobe
- C71.2 Malignant neoplasm of temporal lobe
- C71.3 Malignant neoplasm of parietal lobe
- C71.4 Malignant neoplasm of occipital lobe
- C71.5 Malignant neoplasm of cerebral ventricle
- C71.6 Malignant neoplasm of cerebellum
- C71.7 Malignant neoplasm of brain stem
- C71.8 Malignant neoplasm of overlapping sites of brain
- C71.9 Malignant neoplasm of brain, unspecified
C72 Malignant neoplasm of spinal cord, cranial nerves and other parts of central nervous system14 codes
- C72.0 Malignant neoplasm of spinal cord
- C72.1 Malignant neoplasm of cauda equina
- C72.20 Malignant neoplasm of unspecified olfactory nerve
- C72.21 Malignant neoplasm of right olfactory nerve
- C72.22 Malignant neoplasm of left olfactory nerve
- C72.30 Malignant neoplasm of unspecified optic nerve
- C72.31 Malignant neoplasm of right optic nerve
- C72.32 Malignant neoplasm of left optic nerve
- C72.40 Malignant neoplasm of unspecified acoustic nerve
- C72.41 Malignant neoplasm of right acoustic nerve
- C72.42 Malignant neoplasm of left acoustic nerve
- C72.50 Malignant neoplasm of unspecified cranial nerve
- C72.59 Malignant neoplasm of other cranial nerves
- C72.9 Malignant neoplasm of central nervous system, unspecified
C75 Malignant neoplasm of other endocrine glands and related structures3 codes
C79 Secondary malignant neoplasm of other and unspecified sites4 codes
D32 Benign neoplasm of meninges3 codes
D33 Benign neoplasm of brain and other parts of central nervous system7 codes
- D33.0 Benign neoplasm of brain, supratentorial
- D33.1 Benign neoplasm of brain, infratentorial
- D33.2 Benign neoplasm of brain, unspecified
- D33.3 Benign neoplasm of cranial nerves
- D33.4 Benign neoplasm of spinal cord
- D33.7 Benign neoplasm of other specified parts of central nervous system
- D33.9 Benign neoplasm of central nervous system, unspecified
D35 Benign neoplasm of other and unspecified endocrine glands3 codes
D42 Neoplasm of uncertain behavior of meninges3 codes
D43 Neoplasm of uncertain behavior of brain and central nervous system7 codes
- D43.0 Neoplasm of uncertain behavior of brain, supratentorial
- D43.1 Neoplasm of uncertain behavior of brain, infratentorial
- D43.2 Neoplasm of uncertain behavior of brain, unspecified
- D43.3 Neoplasm of uncertain behavior of cranial nerves
- D43.4 Neoplasm of uncertain behavior of spinal cord
- D43.8 Neoplasm of uncertain behavior of other specified parts of central nervous system
- D43.9 Neoplasm of uncertain behavior of central nervous system, unspecified
D44 Neoplasm of uncertain behavior of endocrine glands3 codes
D49 Neoplasms of unspecified behavior1 code
- D49.6 Neoplasm of unspecified behavior of brain
Procedure Codes
Frequently Asked Questions
What is MS-DRG 55?
MS-DRG 55 (Nervous System Neoplasms without MCC) is a medical DRG in MDC 01 (Diseases & Disorders of the Nervous System). Its FY 2026 relative weight is 1.0196 with a geometric mean length of stay of 2.9 days.
What is the difference between DRG 54, 55?
All 2 share the same base category; the severity of secondary diagnoses separates them: 54 (with MCC), 55 (without MCC). A major complication or comorbidity (MCC) places the case in the highest-weighted DRG of the family; a CC in the middle; neither in the lowest.
How many diagnosis codes group to DRG 55?
61 ICD-10-CM principal diagnosis codes group to this DRG, spanning 12 three-character categories.
What is the relative weight of DRG 55?
The FY 2026 relative weight of this DRG is 1.0196, meaning reimbursement of roughly 1.02 times the average Medicare inpatient case. Multiply by a hospital's blended base rate for the approximate payment.
