2026 ICD-10-CM Diagnosis Code L05.91Pilonidal cyst without abscess
ICD-10-CM Codes›L00–L99›L00-L08›L05
- Billable — Valid for Submission
- Not Chronic
L05.91 is a billable ICD-10-CM diagnosis code for pilonidal cyst without abscess. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 602 through 603. Coders also document this condition as chronic recurrent pilonidal cyst. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Skin and subcutaneous tissue infections.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Chronic recurrent pilonidal cyst
- Pilonidal cyst
- Pilonidal cyst of natal cleft
- Pilonidal disease of natal cleft
- Sacral dimple
- Sacral dimple without abscess
- Skin dimple
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Pilonidal dimple
- Postanal dimple
- Pilonidal cyst NOS
Type 2 Excludes
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
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.
- Cyst(colloid) (mucous) (simple) (retention)
- pilonidal (infected) (rectum)
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Tailbone Disorders
The tailbone is the small bone at the bottom of your backbone, or spine. Tailbone disorders include tailbone injuries, pain, infections, cysts and tumors. You rarely break your tailbone. Instead, most injuries cause bruises or pulled ligaments.
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Convert L05.91 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About L05.91Overview
Is L05.91 (Pilonidal cyst and sinus without abscess) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report pilonidal cyst without abscess on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does L05.91 group to?
When pilonidal cyst without abscess is the principal diagnosis on an inpatient stay, it groups to MS-DRG 602, 603, with relative weights from 0.8709 to 1.4213 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of L05.91?
Under the General Equivalence Mappings, pilonidal cyst without abscess converts to ICD-9-CM 685.1 (pilonidal cyst w/o absc). 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.
