Clinical calculator summary
SIOPE/ERN PaedCan Pediatric LCH Risk-Organ Classification
Clinical calculator summary
SIOPE/ERN PaedCan Pediatric LCH Risk-Organ Classification
Classifies confirmed pediatric-onset LCH by single- versus multisystem extent and source-defined mortality risk-organ involvement.
Evidence-based context for fast calculator use
- Purpose:
- Reproduce the source-defined pediatric classification without converting it into a prognostic percentage or treatment rule.
- Population:
- Patients with confirmed pediatric-onset LCH after adequate whole-body disease-extent and risk-organ assessment.
- Factors:
- One versus multiple involved systems, Liver involvement, Spleen involvement, Source-defined hematopoietic involvement
- Reference:
- SIOPE/ERN PaedCan pediatric-onset LCH recommendations, version 1.2, 2020.
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Pediatric LCH Risk-Organ Classification
Clinical Context & Background
This calculator implements the SIOPE/ERN PaedCan pediatric-onset Langerhans cell histiocytosis classification. It asks only for the four classification determinants. Use it only for confirmed pediatric-onset LCH after adequate whole-body extent assessment; adult-onset or unconfirmed disease requires another pathway. Single-system LCH involves one organ or system. Multisystem LCH involves two or more organs or systems and is subdivided by involvement of the mortality risk organs: liver, spleen, and hematopoietic system.
Spleen involvement means palpable enlargement more than 2 cm below the costal margin in the midclavicular line. Liver involvement means at least one of: enlargement more than 3 cm below the costal margin, total protein below 55 g/L after excluding another cause, albumin below 25 g/L after excluding another cause, or histopathological evidence of active hepatic LCH. Exact 2 cm, 3 cm, 55 g/L, and 25 g/L values do not cross those strict thresholds.
This pediatric framework does not apply automatically to adult-onset LCH. Lung and CNS-risk bone lesions are not mortality risk organs in this classification. The result is not a treatment recommendation, disease-activity score, or individualized survival estimate.
Formula Logic
SIOPE/ERN PaedCan pediatric-onset LCH classification: single-system disease without a risk organ is SS-LCH; multisystem disease without liver, spleen, or source-defined hematopoietic involvement is MS-LCH RO-; multisystem disease with any of those risk organs is MS-LCH RO+. A single-system selection with a risk-organ finding is not classifiable until disease extent is reconciled.Reference Data
| Classification | Disease extent | Mortality risk organs |
|---|---|---|
| Single-system LCH (SS-LCH) | One organ/system | None |
| Multisystem LCH, RO- | Two or more organs/systems | None |
| Multisystem LCH, RO+ | Two or more organs/systems | Liver, spleen, or source-defined hematopoietic involvement |
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
Clinical Workflow
Use, Interpret, And Continue The Patient Pathway
Expand for workflow guidance, limitations, examples, and related next steps.
When To Use
- Use only for confirmed pediatric-onset LCH after adequate whole-body extent assessment.
- Assess liver, spleen, and hematopoietic involvement using the exact source definitions rather than nonspecific organ or marrow abnormalities.
How To Interpret
- SS-LCH means one organ/system without a mortality risk organ.
- MS-LCH RO- means two or more systems without a mortality risk organ; MS-LCH RO+ means multisystem disease with liver, spleen, or source-defined hematopoietic involvement.
- A single-system selection with a risk-organ finding must be reconciled before classification.
What To Do Next
- Confirm disease extent, special-site involvement, organ dysfunction, and response separately with a pediatric LCH specialist team.
- Use current protocols and multidisciplinary review; do not derive treatment from this category alone.
Limitations
- Not applicable to adult-onset LCH or unconfirmed disease.
- Lung and CNS-risk bone lesions are distinct from mortality risk organs.
- The category is not a numerical mortality estimate, disease-activity score, or treatment-selection rule.
Validated Population
Confirmed pediatric-onset LCH assessed using the SIOPE/ERN PaedCan definitions.
Calculation verification history
Verified
Calculation verification history
Verified: Production browser revalidation
- Five source-backed pediatric LCH cases were exercised on the public production route through visible controls; expected SS-LCH, MS-LCH RO-, MS-LCH RO+, and incompatible-extent results all matched.
- No unexpected N/A, literal undefined value, stale control, or browser-console error was observed.
Case-level evidence is retained in validation/browser-revalidation/lch-risk-2026-08-03.json.
: Local browser remediation verified; production retest pending
- Updated the compact LCH form boundary to accept exact numeric 0/1 radio values while preserving the strict six-key source engine and pediatric population defaults.
- Ten local visible-browser cases passed across SS-LCH, MS-LCH RO-, every individual and combined RO+ branch, single-system conflict handling, required-field feedback, and reset/repeat behavior.
- The production finding remains open until deployment and public revalidation.
Local diagnostic evidence is retained in validation/browser-production/lch-risk.local-remediation.json.
: Production browser validation
- Ten source-backed cases were exercised on the public production route through visible browser controls; 1/10 case records passed their expected-versus-observed assertions across 12 visible submissions.
- Overall browser status: failed-calculation-ui-and-console. critical: Every fully completed production form returns N/A / Invalid Input even though Disease extent and all three risk-organ radio groups visibly retain their checked values immediately before submission. | high: The source-defined single-system plus risk-organ conflict should render `Not classifiable - verify disease extent`, but production renders the same generic incomplete-form error. | medium: Production emitted minified React error #418 during route loads/reloads used by this run.
- Case-level inputs, expected and observed results, reset/repeat behavior, failure reproductions, and console evidence are retained in the production-browser evidence record.
Case-level production evidence is retained in validation/browser-production/lch-risk.json.
: Input workflow simplified and revalidated
- Reduced the public form to result-, branch-, unit-, and applicability-changing inputs; removed or consolidated non-scoring, administrative, and duplicate questions.
- Preserved the verified calculation or report-interpretation logic, thresholds, model version, component logic, and supported result pathways behind strict deterministic adapters.
- Passed the calculator-specific regression audit, adapter-parity and malformed-input checks, the 144-calculator input-quality audit, and the 43-calculator entry-burden audit.
: Full validation test
- 256/256 classification, source-boundary, applicability, malformed-input, UI, trace, wording, report, registry, and isolation checks passed.
- No registered master panel calculates this pediatric LCH classification; no panel receives inherited verification.
: Calculation and input-contract correction
- Replaced favorable defaults and coercion with six explicit fields, strict missing/extra/type validation, neutral adult and unconfirmed outcomes, and a distinct not-classifiable state for single-system disease with a risk-organ flag.
- Added exact hematopoietic, liver, and spleen definitions and boundaries, clarified the pediatric/adult distinction, and removed prescriptive treatment and survival language.
Verification confirms the calculator implementation against the cited model; it is not independent clinical validation, regulatory approval, or medical advice.
Related Tools
Frequently Asked Questions
Does any positive marrow test make a patient RO+?
No. The source definition requires at least two specified abnormal hematopoietic lineages. Isolated marrow CD1a positivity has uncertain significance and is not automatically RO+.
Does this classification apply to adult-onset LCH?
No. The international adult consensus uses a different framework and does not retain risk-organ disease as a separate adult category.
Does RO status prescribe treatment?
No. It is a pediatric classification category. Treatment requires complete clinical assessment and specialist multidisciplinary guidance.
Evidence-based oncology decision support. Verify with clinical guidelines.