12-phase flow (12)

1. 1FRAME
   Frame as a NOT-TO-MISS: the dermatology engine owns recognition → diagnostic excisional biopsy → histopath-driven AJCC8 staging → wide local excision + SLNB + surveillance, and ROUTES advanced/adjuvant systemic therapy to oncology by engine_id (onc.melanoma-systemic.core.v1) while co-managing checkpoint-inhibitor cutaneous toxicity. Early thin melanoma is highly curable; the failure mode is delayed recognition/biopsy and the amelanotic/nodular/subungual misses (AAD 2019 PMID 30392755).
   advance: derm-scope set; systemic-therapy + NMSC + irAE routes noted by engine_id
2. 2ENTRY
   Recognise a new/changing/symptomatic pigmented lesion, a rapidly growing nodular/amelanotic lesion, a Hutchinson-positive nail, or a high-risk surveillance/established-melanoma entry; capture ABCDE + change history up front (the core recognition signal).
   inputs: lesion_abcde_and_change_history
   actions: workup.chronic_pruritus
   advance: entry trigger present; ABCDE + change history recorded
3. 3CONTEXT
   Build the recognition context: dermoscopy (atypical network, blue-white veil, irregular streaks/dots, regression, negative network), ugly-duckling judgement on a total-body skin exam, melanoma risk-factor stratification (UV/fair skin/≥50 nevi/atypical-nevus syndrome/family/CDKN2A/immunosuppression), and special-site features (acral, subungual Hutchinson) that are commonly delayed in skin of colour.
   inputs: dermoscopy_findings, ugly_duckling_and_total_body_context, melanoma_risk_factors, special_site_features
   actions: workup.chronic_pruritus
   advance: risk-conditioned pre-test prior + total-body context established
4. 4RED_FLAGS
   Do NOT monitor a high-suspicion lesion — a clinically/dermoscopically suspicious lesion goes to urgent diagnostic excisional biopsy. Screen the not-to-miss amelanotic/bleeding nodular melanoma, regional nodal / satellite-in-transit disease, and metastatic visceral or brain-metastasis symptoms; checkpoint-inhibitor severe irAE (colitis/hepatitis/pneumonitis/myocarditis) in a patient on routed systemic therapy is an emergent route-out.
   inputs: amelanotic_or_bleeding_nodular_lesion, regional_node_or_in_transit_signs, metastatic_systemic_or_neuro_symptoms
   actions: panel.cbc, panel.inflammation
   advance: suspicious lesion routed to urgent biopsy; nodal/metastatic/irAE red flags screened and escalated/routed if present
5. 5INITIAL_WORKUP
   DIAGNOSTIC EXCISIONAL BIOPSY with 1–3 mm clinical margins to depth (or full-thickness punch/incisional through the thickest/most atypical area when complete excision is impractical — NOT a superficial shave for a deep or uncertain pigmented lesion, which truncates Breslow). Synoptic histopathology: Breslow thickness, ulceration, dermal mitotic rate, Clark level (legacy), subtype (superficial spreading / nodular / lentigo maligna / acral lentiginous), microsatellites, lymphovascular invasion, peripheral/deep margins. Baseline CBC/LFT only if systemic therapy is anticipated — routine bloods/imaging are NOT indicated for asymptomatic stage 0–II (AAD 2019 PMID 30392755).
   inputs: biopsy_breslow_ulceration_mitoses_subtype, cbc_with_differential, lft
   actions: panel.cbc, panel.lft
   advance: definitive biopsy obtained with adequate technique; synoptic histopathology + Breslow/ulceration/mitoses/subtype reported
6. 6BRANCHING_WORKUP
   Histopath-driven branch: melanoma in situ → margin re-excision only; invasive → AJCC8 T-category from Breslow + ulceration → SLNB DISCUSSION at ≈T1b (≥0.8 mm, or <0.8 mm with ulceration) and offered for all ≥T2 (MSLT-I prognostic PMID 24521106; SLN+ does NOT mandate completion lymphadenectomy — nodal US surveillance is non-inferior, MSLT-II PMID 28591523). Stage-directed imaging: none/US for low stage; CT/PET-CT + brain MRI + LDH for node-positive/high stage. BRAF V600 (+ NRAS/c-KIT for acral/mucosal) molecular testing on stage III–IV / unresectable disease, carried with the patient to oncology.
   inputs: staging_imaging_by_stage, braf_nras_ckit_molecular
   actions: workup.le_edema, panel.inflammation
   advance: AJCC8 stage assigned; SLNB candidacy decided; stage-directed imaging + molecular testing ordered as indicated
7. 7DIFFERENTIAL
   Terminal pigmented-lesion differential with named pivots: melanoma vs benign acquired nevus (symmetric, stable, regular network pivot) vs dysplastic/atypical nevus (mild irregularity, monitor-vs-excise pivot) vs seborrheic keratosis (stuck-on, milia-like cysts + comedo-like openings pivot) vs pigmented basal cell carcinoma (arborising vessels + leaf-like areas, route derm.actinic-keratosis-nmsc.core.v1) vs solar lentigo / ink-spot lentigo (uniform fingerprint pattern pivot) vs blue nevus (homogeneous steel-blue, long-stable pivot) vs dermatofibroma (central white scar-like patch + dimple sign pivot) vs subungual haematoma (resolving, moves out with growth, no Hutchinson — vs subungual melanoma) vs pyogenic granuloma (rapid friable vascular nodule — vs amelanotic nodular melanoma) vs angiokeratoma (dark vascular lacunae pivot). When in doubt, biopsy — recognition errors are the dominant harm.
   advance: single best diagnosis selected, or biopsy performed because melanoma cannot be confidently excluded
8. 8RISK_STRATIFICATION
   AJCC 8th-edition staging (schema-blocked as a TS calculator — captured narratively): T from Breslow + ulceration (Tis; T1a <0.8 mm non-ulcerated; T1b 0.8–1.0 mm or <0.8 mm ulcerated; T2 >1–2; T3 >2–4; T4 >4 mm), N from SLN/clinical nodes + microsatellites/in-transit, M from site + serum LDH (M1a/b/c/d, [0] normal vs [1] elevated LDH). Stage drives margin, SLNB, imaging, surveillance cadence and adjuvant-therapy routing.
   inputs: ldh, biopsy_breslow_ulceration_mitoses_subtype
   actions: panel.inflammation
   advance: AJCC8 clinical/pathologic stage assigned; LDH incorporated for metastatic disease
9. 9TREATMENT
   DERMATOLOGY-OWNED definitive local therapy: wide local excision with AJCC8/AAD stage-based margins (in situ 0.5–1.0 cm; ≤1.0 mm → 1 cm; >1–2 mm → 1–2 cm; >2 mm → 2 cm) (non-pharm); SLNB at the same setting per criteria (non-pharm); lentigo maligna where wide margins are unfeasible → staged/Mohs excision, or topical imiquimod / definitive radiotherapy (AAD 2019 PMID 30392755). Resected stage III / high-risk II and unresectable/metastatic disease: ADJUVANT and ADVANCED systemic therapy (anti-PD-1, ipilimumab+nivolumab, nivolumab+relatlimab, BRAF/MEK for BRAF-mutant, neoadjuvant per SWOG S1801, T-VEC for select in-transit) are recognised and ROUTED to onc.melanoma-systemic.core.v1 by engine_id; dermatology co-manages checkpoint-inhibitor cutaneous toxicity. Gate on pregnancy (excision safe; defer systemic), immunosuppression/transplant (checkpoint-inhibitor graft-rejection caution), and BRAF status (BRAFi only if BRAF-mutant — BRAFi monotherapy in BRAF-wildtype can paradoxically activate MAPK).
   inputs: pregnancy_status, immunosuppression_or_transplant, creatinine
   advance: WLE ± SLNB plan set with correct stage-based margins; lentigo-maligna alternative chosen if applicable; systemic therapy routed to oncology with carryover
10. 10DISPOSITION
    Almost entirely outpatient: WLE ± SLNB as a day procedure; surveillance in derm/onco-derm clinic. Inpatient/urgent referral only for bulky nodal/in-transit disease needing oncologic surgery, symptomatic metastatic disease, brain metastasis, or severe checkpoint-inhibitor irAE (routed). Multidisciplinary tumour-board referral for stage ≥III; oncology shared-care for any systemic therapy.
    inputs: regional_node_or_in_transit_signs, metastatic_systemic_or_neuro_symptoms
    advance: disposition documented; MDT/oncology referral made for stage ≥III; systemic therapy delegated by engine_id
11. 11MONITORING
    Stage-stratified surveillance (AAD 2019 PMID 30392755): history + total-body skin + regional-node exam every 6–12 mo for low-risk stage 0–I, every 3–6 mo for stage II–IV (years 1–2) extending intervals over time, lifelong skin self-exam education; nodal ultrasound for SLN+ on observation (MSLT-II PMID 28591523); stage-directed cross-sectional/brain imaging + LDH for higher stages. For patients on routed systemic therapy, dermatology co-monitors immune cutaneous toxicity and surfaces severe irAE (thyroid/hepatitis/colitis/pneumonitis/dermatitis/myocarditis) for emergent oncology routing; BRAF/MEK toxicity (pyrexia, ocular, cardiac, cutaneous) per oncology.
    inputs: ldh, cbc_with_differential
    actions: panel.cbc, panel.lft, panel.inflammation
    advance: stage-appropriate surveillance schedule set; irAE/targeted-toxicity co-monitoring defined for routed-systemic patients
12. 12FOLLOWUP
    Lifelong derm continuity: scheduled total-body skin exams (second-primary risk is elevated for life — ~ up to 5–10% lifetime second melanoma), structured skin self-examination + partner-assisted nail/scalp/acral checks, photoprotection counselling, surveillance imaging cadence by stage, and first-degree-relative + CDKN2A familial counselling (incl. pancreatic-cancer surveillance discussion in CDKN2A kindreds). Re-stage and re-route to oncology on recurrence/in-transit/new-primary; reconcile any checkpoint-inhibitor cutaneous irAE with derm.drug-eruption.core.v1.
    inputs: melanoma_risk_factors, special_site_features
    actions: workup.chronic_pruritus
    advance: lifelong surveillance + self-exam + photoprotection + familial counselling documented; recurrence/second-primary re-entry path defined