A 79-year-old former farmer presents with a rapidly enlarging, painless, red-violaceous nodule overlying the right parotid region, present for 5 weeks.
Diagnosis
Merkel cell carcinoma of the cheek — AEIOU, SLNB and adjuvant RT, with avelumab if disease recurs
Learning points
AEIOU mnemonic: Asymptomatic, Expanding rapidly, Immunosuppressed, Older than 50, UV-exposed fair skin. ≥ 3 features should raise suspicion of MCC.
CK20 perinuclear dot, synaptophysin and chromogranin A positive; TTF1 negative (excludes metastatic small-cell lung).
About 70–80% of UK MCC is MCPyV-driven; the rest is UV-induced with much higher mutational burden.
Standard localised management: WLE 1–2 cm clinical margin + SLNB + adjuvant RT to primary site (and nodal basin for SLN+).
NICE TA691 (2021) recommends avelumab (anti-PD-L1) first-line for untreated metastatic MCC. Pembrolizumab has phase 2 evidence in advanced MCC (KEYNOTE-017) but no NICE pembrolizumab MCC TA was identified on live checking; confirm any local or national access route before use.
Adjuvant ICI in MCC is the subject of ongoing trials (ADAM, ADMEC-O) — not yet a routine NICE-recommended indication.
Source basis
This page was launch-reviewed on 19 May 2026. See the source-control register for the NICE, NHS England, BAD, RCPath, WHO, AJCC / TNM and pivotal-trial sources used across the site; check live guidance and local MDT policy before applying recommendations.
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