2026 ICD-10-CM Diagnosis Code B45.1Cerebral cryptococcosis

ICD-10-CM Codes›A00–B99›B35-B49›B45

ICD-10-CM B45.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B45.1 is a billable ICD-10-CM diagnosis code for cerebral cryptococcosis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as cerebral cryptococcoma. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Fungal infections and Meningitis.

Code Identity

ICD-10-CM Code
B45.1
Billable Status
Yes — Valid for Submission
Code Describes
Cerebral cryptococcosis
Short Description
Cerebral cryptococcosis
Same as the full description in the CMS dataset.
Parent Code
B45
Cryptococcosis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB35-B49Mycoses
CategoryB45Cryptococcosis
This CodeB45.1Cerebral cryptococcosis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cerebral cryptococcoma
  • Cerebral cryptococcosis
  • Cryptococcal meningitis
  • Cryptococcus infection of the central nervous system
  • Fungal infection of cerebrum
  • Fungal meningitis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Cryptococcal meningitis
  • Cryptococcosis meningocerebralis

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.

    • Cryptococcosis, cryptococcus(infection) (neoformans)
      • cerebral
    • Cryptococcosis, cryptococcus(infection) (neoformans)
      • meningitis
    • Cryptococcosis, cryptococcus(infection) (neoformans)
      • meningocerebralis
    • Encephalitis(chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute)
      • Torula, torular (cryptococcal)
    • Meningitis(basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic)
      • cryptococcal
    • Meningitis(basal) (basic) (brain) (cerebral) (cervical) (congestive) (diffuse) (hemorrhagic) (infantile) (membranous) (metastatic) (nonspecific) (pontine) (progressive) (simple) (spinal) (subacute) (sympathetic) (toxic)
      • Torula histolytica (cryptococcal)
    • Meningoencephalomyelitis
      • due to
        • Torula
    • Meningomyelitis
      • cryptococcal

Clinical ClassificationClinical

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

CCSR INF004
Fungal infections
Default principal diagnosis: inpatient No · outpatient No
CCSR NVS001
Meningitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Cryptococcal Meningitis

    a blood borne fungal infection of the membranes surrounding the brain and spinal column (meninges) caused by cryptococcus, usually c. neoformans or c. gattii. it usually occurs in immunocompromised patients including persons with aids, transplant recipients, patients receiving cytotoxic chemotherapy, and patients with hematologic malignancies.

Patient EducationClinical

Fungal Infections

If you have ever had athlete's foot or a yeast infection, you can blame a fungus. A fungus is a primitive organism. Mushrooms, mold and mildew are examples. Fungi live in air, in soil, on plants and in water. Some live in the human body. Only about half of all types of fungi are harmful.

Read the full article at MedlinePlus

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

Convert B45.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
117.5 Cryptococcosis
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
321.0 Cryptococcal meningitis
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About B45.1Overview

Is B45.1 (Cryptococcosis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report cerebral cryptococcosis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of B45.1?

Under the General Equivalence Mappings, cerebral cryptococcosis converts to ICD-9-CM 117.5 (cryptococcosis) and 321.0 (cryptococcal meningitis). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.