Lymphomatoid papulosis
LyP; CD30-positive lymphoproliferative disorder of the skin (with primary cutaneous anaplastic large-cell lymphoma)
Lymphomatoid papulosis is a chronic, recurrent, self-healing papulonodular eruption that paradoxically combines histologically malignant-appearing CD30-positive T-cell infiltrates with a benign clinical course. It belongs to the spectrum of primary cutaneous CD30+ lymphoproliferative disorders along with primary cutaneous anaplastic large-cell lymphoma (pcALCL). Six histological subtypes (A–F) are recognised. Up to 10–20% of patients develop another lymphoma during their lifetime — most commonly mycosis fungoides, pcALCL or Hodgkin lymphoma — so long-term surveillance is necessary.
Clinical features
- Crops of erythematous papules and nodules, often itchy, in various stages of evolution.
- Individual lesions ulcerate, crust over and resolve spontaneously over 2–8 weeks, often leaving atrophic varioliform scars.
- New crops develop while old lesions resolve — characteristic feature.
- Trunk and limbs most often affected; face spared.
- Median onset 35–45; M:F roughly equal; rare in children but well described.
Histology & subtypes
- Wedge-shaped infiltrate of CD30+ atypical lymphocytes admixed with reactive inflammatory cells.
- Histological subtypes (A through F) — relevant for prognosis and differential rather than treatment:
- A (most common) — large CD30+ blasts with mixed inflammation.
- B — small to medium pleomorphic, mycosis-fungoides-like.
- C — sheets of CD30+ cells (mimics ALCL).
- D — CD8+ epidermotropic cytotoxic.
- E — angioinvasive / angiocentric (eschar-like ulcers).
- F — folliculotropic.
- DUSP22-IRF4 (6p25.3) rearranged variant — an increasingly recognised molecular subgroup across the CD30+ LPD spectrum; biphasic histology with small epidermotropic and large dermal components, relevant to the distinction from pcALCL.
- CD3+, CD4+, CD30+ T cells (usually); ALK negative — this distinguishes LyP and pcALCL together from systemic ALK+ ALCL, but does not on its own distinguish LyP from pcALCL (which is also ALK negative).
- Clonal T-cell receptor rearrangement in >70%.
Differential diagnosis
- Primary cutaneous anaplastic large-cell lymphoma (pcALCL) — solitary or grouped large nodules without spontaneous regression; histology overlaps; clinical context distinguishes.
- Pityriasis lichenoides et varioliformis acuta (PLEVA) — clinically similar; often considered part of the same spectrum.
- Insect bites, folliculitis, prurigo — clinical mimics.
- Systemic ALK+ ALCL with skin involvement — staging is essential.
Management
- No treatment / observation is appropriate for many patients given spontaneous resolution.
- Topical corticosteroids for symptom relief.
- Phototherapy (PUVA, narrowband UVB) for widespread or symptomatic disease.
- Low-dose oral methotrexate (10–25 mg weekly) — most effective long-term suppressive therapy.
- Brentuximab vedotin (NICE TA577) for refractory disease and pcALCL — see monograph.
- Bexarotene, interferon-α — alternatives.
- Avoid aggressive systemic chemotherapy — does not change natural history and risks more harm than the disease.
Surveillance
- Long-term clinical follow-up (annually after stability achieved) for the lifetime risk of associated lymphoma (10–20%).
- Investigate any persistent, non-regressing lesion or systemic symptoms — repeat biopsy and consider staging.
- Patient education to flag rapid growth, ulceration, lymphadenopathy or B symptoms.
References
- Bekkenk MW et al. Primary and secondary cutaneous CD30+ lymphoproliferative disorders. Blood; 2000.
- Willemze R et al. The 2018 update of the WHO-EORTC classification for primary cutaneous lymphomas. Blood; 2019.
- WHO Classification of Haematolymphoid Tumours, 5th edition (WHO-HAEM5); 2022. International Consensus Classification of Mature Lymphoid Neoplasms; 2022.
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