L91.9Hypertrophic disorder of the skin, unspecified

L91.9 is the ICD-10-CM diagnosis code for hypertrophic disorder of the skin, unspecified. It belongs to category L91 (hypertrophic disorders of skin), block L80-L99 (other disorders of the skin and subcutaneous tissue) and chapter 12 (diseases of the skin and subcutaneous tissue). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within L91, choose L91.9 (Hypertrophic disorder of the skin, unspecified) only when documentation doesn't support a more specific option: hypertrophic scar (L91.0) and other hypertrophic disorders of the skin (L91.8).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 606 (Minor Skin Disorders with MCC, relative weight 1.5728) and DRG 607 (Minor Skin Disorders without MCC, relative weight 0.8772), in MDC 09 (Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 701.9 (unspecified hypertrophic and atrophic conditions of skin).