L41.4 ICD-10-CM Code: Large plaque parapsoriasis
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the skin and subcutaneous tissue (L00-L99) / Papulosquamous disorders (L40-L45)
L41.4
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceLarge plaque parapsoriasis
A form of parapsoriasis with larger patches of skin inflammation that may cover more extensive body areas.
Buddy Insight
Large plaque parapsoriasis is a chronic dermatosis with significant clinical importance because approximately 10-35% of cases may progress to cutaneous T-cell lymphoma (mycosis fungoides).
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
MappedHCC 316
RAF 0.0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for L41.4 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for L41.4 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for L41.4 in this effective period.
Excludes 1
Official- poikiloderma vasculare atrophicans (L94.5)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for L41.4 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for L41.4 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for L41.4 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is L41.4 an HCC code?
No. L41.4 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for L41.4
For L41.4to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed L41.4 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
L41.4 is the ICD-10-CM diagnosis code for large plaque parapsoriasis. A form of parapsoriasis with larger patches of skin inflammation that may cover more extensive body areas. L41.4 sits in the ICD-10-CM chapter for diseases of the skin and subcutaneous tissue (l00-l99), within the section covering papulosquamous disorders (l40-l45).
L41.4 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Does not map to any CMS-HCC in V28, V24, or ESRD models. Maps only to RxHCC 316 (Psoriasis and Other Papulosquamous Disorders) for prescription drug risk adjustment. Despite its pre-malignant potential, it does not carry Medicare Advantage RAF weight. If it transforms to mycosis fungoides, the malignancy code would carry HCC weight.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for L41.4 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm the size of lesions (larger than small plaque parapsoriasis) and document the extent of body surface involvement
- •Differentiate from mycosis fungoides and other cutaneous lymphomas through clinical and histological findings
Clinical Significance
Large plaque parapsoriasis is a chronic dermatosis with significant clinical importance because approximately 10-35% of cases may progress to cutaneous T-cell lymphoma (mycosis fungoides). This makes it a pre-malignant condition requiring regular monitoring with serial biopsies. Early detection of malignant transformation is critical for timely intervention and improved outcomes.
Documentation Requirements
- ✓Provider documentation of large plaque parapsoriasis
- ✓Description of plaque characteristics (typically >5 cm, atrophic or poikilodermatous)
- ✓Biopsy results with attention to T-cell clonality
- ✓Surveillance schedule for repeat biopsies
- ✓Current treatment plan (phototherapy, topical steroids)
- ✓Assessment for features suggestive of malignant transformation
Commonly Confused Codes
- •L41.3 (Small plaque parapsoriasis) — smaller patches with much lower malignant potential
- •C84.0 (Mycosis fungoides) — may evolve from large plaque parapsoriasis; code mycosis fungoides when confirmed
- •L40.0 (Psoriasis vulgaris) — psoriasis has silvery scale and different histology
- •L41.5 (Retiform parapsoriasis) — net-like pattern variant