2026 ICD-10-CM Diagnosis Code M35.89Other specified systemic involvement of connective tissue

ICD-10-CM Codes›M00–M99›M30-M36›M35

ICD-10-CM M35.89
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M35.89 is a billable ICD-10-CM diagnosis code for other specified systemic involvement of connective tissue. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 545 through 547. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Systemic lupus erythematosus and connective tissue disorders.

Code Identity

ICD-10-CM Code
M35.89
Billable Status
Yes — Valid for Submission
Code Describes
Other specified systemic involvement of connective tissue
Short Description
Other specified systemic involvement of connective tissue
Same as the full description in the CMS dataset.
Parent Code
M35.8
Other specified systemic involvement of connective tissue

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM30-M36Systemic connective tissue disorders
CategoryM35Other systemic involvement of connective tissue
This CodeM35.89Other specified systemic involvement of connective tissue

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Antisynthetase syndrome
  • Anti-synthetase syndrome due to dermatomyositis
  • Antisynthetase syndrome due to polymyositis
  • Collagen deficiency syndrome
  • Cranial cerebrospinal fluid leak
  • EMILIN-1-related connective tissue disease
  • Eosinophilia myalgia syndrome
  • Eosinophilia-myalgia syndrome from tryptophan
  • Leak of cranial cerebrospinal fluid due to collagen deficiency syndrome
  • Marden Walker syndrome
  • Muscle eosinophilia
  • Polyneuropathy in collagen malignant disease
  • Satoyoshi syndrome

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Collagenosis, collagen disease(nonvascular) (vascular)
      • specified NEC
    • Disease, diseased
      • collagen NOS (nonvascular) (vascular)
        • specified NEC
    • Disease, diseased
      • connective tissue, systemic (diffuse)
        • specified NEC
    • Eosinophilia-myalgia syndrome
    • Syndrome
      • eosinophilia-myalgia

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MUS024
Systemic lupus erythematosus and connective tissue disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Autoimmune Hypophysitis|Lymphocytic Hypophysitis

    an autoimmune condition affecting the pituitary gland, characterized by lymphocytic infiltration, commonly presenting with pituitary hormone deficiencies.

  • Grade 1 Hypophysitis, CTCAE|Grade 1 Hypophysitis

    asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention not indicated

  • Grade 2 Hypophysitis, CTCAE|Grade 2 Hypophysitis

    moderate; minimal, local or noninvasive intervention indicated; limiting age-appropriate instrumental adl

  • Grade 3 Hypophysitis, CTCAE|Grade 3 Hypophysitis

    severe or medically significant but not immediately life-threatening; hospitalization or prolongation of existing hospitalization indicated; limiting self care adl

  • Grade 4 Hypophysitis, CTCAE|Grade 4 Hypophysitis

    life-threatening consequences; urgent intervention indicated

  • Grade 5 Hypophysitis, CTCAE|Grade 5 Hypophysitis

    death

  • Hypophysitis

    an inflammatory process in the pituitary gland.

  • Hypophysitis, CTCAE|Hypophysitis

    a disorder characterized by inflammation and cellular infiltration of the pituitary gland.

  • Lymphocytic Neurohypophysitis

    an autoimmune condition affecting the posterior pituitary gland, which is characterized by lymphocytic infiltration, and which often presents as diabetes insipidus.

Patient EducationClinical

Connective Tissue Disorders

Your connective tissue supports many different parts of your body, such as your skin, eyes, and heart. It is like a "cellular glue" that gives your body parts their shape and helps keep them strong. It also helps some of your tissues do their work. It is made of many kinds of proteins. Cartilage and fat are types of connective tissue.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code History & ChangesHistory

Replacement M35.89 replaces the following previously assigned code(s):

  • M35.8 - Other specified systemic involvement of connective tissue
FY 2022AddedAdded to the ICD-10-CM code setEffective October 1, 2021.
FY 2023–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About M35.89Overview

Is M35.89 (Other specified systemic involvement of connective tissue) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other specified systemic involvement of connective tissue on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M35.89 group to?

When other specified systemic involvement of connective tissue is the principal diagnosis on an inpatient stay, it groups to MS-DRG 545, 546, 547, with relative weights from 0.8362 to 2.4817 depending on complications. Higher weights mean higher Medicare reimbursement.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.