Bazex paraneoplastic acrokeratosis
Acrokeratosis paraneoplastica of Bazex; "acrokeratosis paraneoplastica"; (NB — entirely distinct from Bazex-Dupré-Christol syndrome, which is a hereditary BCC syndrome)
Bazex paraneoplastic acrokeratosis — also called "acrokeratosis paraneoplastica" — is a striking psoriasiform paraneoplastic dermatosis with a near-pathognomonic association with squamous cell carcinoma of the upper aerodigestive tract. The eruption begins acrally — on the helices and pinnae of the ears, nose, fingers and toes — as violaceous to red-purple psoriasiform plaques with hyperkeratosis, then progresses centripetally to involve the dorsa of the hands, feet, knees, elbows and eventually the central face and trunk. Nail dystrophy with onycholysis and subungual hyperkeratosis is universal. Critically, the dermatosis precedes the diagnosis of the underlying malignancy in ~70% of cases, providing a major diagnostic opportunity for early cancer detection. Treatment of the underlying cancer (head / neck / oesophageal SCC, lung SCC, less commonly other malignancies) typically resolves the eruption.
Clinical features
- Phase 1 (acral):
- Violaceous to red-purple psoriasiform plaques on the helices of the ears, nose, fingers and toes.
- Hyperkeratotic, scaly, well-demarcated.
- Nail dystrophy — onycholysis, subungual hyperkeratosis, longitudinal / transverse ridging — universal.
- Symmetric.
- Asymptomatic or mildly itchy.
- Phase 2 (centripetal extension) — palms, soles, dorsa of hands and feet, knees, elbows, cheeks.
- Phase 3 (generalised) — trunk involvement; only develops without diagnosis or treatment of the underlying tumour.
- Median age 40–60; M:F ~10:1 (strongly male-predominant).
- Almost universally heralds underlying squamous cell carcinoma of:
- Upper aerodigestive tract (head / neck SCC, oesophageal SCC, oropharyngeal SCC) — >80%.
- Lung (squamous, adenocarcinoma).
- Less commonly: cervix, prostate, breast, GI, lymphoma.
- The dermatosis precedes the cancer diagnosis in ~70%; concurrent in ~15%; follows in ~15%.
Histology
- Non-specific psoriasiform pattern with hyperkeratosis, parakeratosis, mild epidermal acanthosis and superficial perivascular lymphohistiocytic infiltrate.
- Sometimes vacuolar interface change.
- Histology cannot distinguish Bazex paraneoplastic acrokeratosis from psoriasis or other psoriasiform dermatoses — diagnosis depends on the characteristic clinical picture and identification of the underlying malignancy.
- Direct immunofluorescence — negative or non-specific.
Differential diagnosis
- Psoriasis — particularly palmoplantar / acral / nail psoriasis. Bazex acrokeratosis is more violaceous, more strikingly acral, develops in older men, has the characteristic ear involvement, and resolves with treatment of the underlying cancer.
- Pityriasis rubra pilaris — orange-red plaques, follicular keratoses, palmoplantar hyperkeratosis, "islands of sparing".
- Reiter syndrome / reactive arthritis — keratoderma blennorrhagicum.
- Drug-induced psoriasiform eruption — clear precipitant.
- Tinea unguium / pedis — confirm with mycology.
- Chilblains — winter occurrence; spontaneous resolution.
- Discoid lupus erythematosus — particularly when ear-predominant.
Cancer workup
- Full history and examination — particularly oropharyngeal, ENT, smoking, alcohol, weight loss, dysphagia, hoarseness, haemoptysis.
- FBC, U&E, LFT, calcium.
- ENT examination including flexible laryngoscopy — first-line for upper aerodigestive SCC.
- CT chest, neck, abdomen, pelvis ± PET-CT.
- Upper GI endoscopy with biopsy.
- Tumour markers (SCCA, CEA, CA19-9, CA125, AFP, PSA — guided by symptoms).
- Mammography (women); cervical screening up to date.
- Refer to head / neck oncology / lung MDT as indicated.
Management
- Treat the underlying malignancy — the eruption typically resolves with successful tumour treatment and recurs with relapse, providing a useful clinical marker of disease activity.
- Symptomatic skin care:
- Bland emollients.
- Topical corticosteroids (modest efficacy).
- Topical / oral retinoids.
- Keratolytics (urea, salicylic acid).
- PUVA / narrowband UVB (variable efficacy).
- Multidisciplinary cancer care — head / neck / lung oncology MDT.
- Counsel about prognostic implications — Bazex paraneoplastic acrokeratosis frequently signals advanced or metastatic upper aerodigestive SCC.
References
- Bolognia JL et al. Bazex syndrome — acrokeratosis paraneoplastica. Medicine (Baltimore); 1991.
- Sator PG et al. Acrokeratosis paraneoplastica (Bazex syndrome) — review. J Eur Acad Dermatol Venereol; 2006.
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