BACKGROUND: Lymphomatoid papulosis (LyP) is an uncommon cutaneous T-cell lymphoproliferative disorder (CTLPD) rarely encountered in children. OBJECTIVES: To specify characteristics of paediatric LyP and to describe both diagnostic difficulties and the course of the disease with the experience of 10 years' follow-up. METHODS: This was a retrospective, single-centre study of 25 children diagnosed with LyP according to the 2008 World Health Organization guidelines, and a clinical and pathological correlation by two experts. RESULTS: The mean age at onset was 7·5 years. The lesions were mostly papulonodular with frequent pruritus (40%). Mucosal involvement was sometimes observed. A single ulcerative nodule was initially suggestive of a primary cutaneous anaplastic large-cell lymphoma (C-ALCL). Pityriasis lichenoides was associated in 36% of cases, atopic dermatitis in 28% and nonspecific infections in 28%. Complete remission was observed in 44% of cases. Through the mean follow-up of 10 years, none of our patients have experienced lymphoma occurrence. Histopathological subtype A clearly predominated (82%). A marked eosinophilic infiltrate was present in 44% of cases and a cutaneous T-gamma clone in 40%. No correlation was observed between histopathological subtype, cutaneous clone or LyP clinical course. CONCLUSIONS: Paediatric LyP belongs to the group of CD30-positive CTLPDs including C-ALCL. Children have to be carefully followed up lifelong, even if the prognosis appears good. The high frequencies of an associated viral infection, atopic dermatitis, marked eosinophilic infiltrate and a good outcome suggest that paediatric LyP could be considered a reactional disease rather than a malignant disorder.
BACKGROUND:Lymphomatoid papulosis (LyP) is an uncommon cutaneous T-cell lymphoproliferative disorder (CTLPD) rarely encountered in children. OBJECTIVES: To specify characteristics of paediatric LyP and to describe both diagnostic difficulties and the course of the disease with the experience of 10 years' follow-up. METHODS: This was a retrospective, single-centre study of 25 children diagnosed with LyP according to the 2008 World Health Organization guidelines, and a clinical and pathological correlation by two experts. RESULTS: The mean age at onset was 7·5 years. The lesions were mostly papulonodular with frequent pruritus (40%). Mucosal involvement was sometimes observed. A single ulcerative nodule was initially suggestive of a primary cutaneous anaplastic large-cell lymphoma (C-ALCL). Pityriasis lichenoides was associated in 36% of cases, atopic dermatitis in 28% and nonspecific infections in 28%. Complete remission was observed in 44% of cases. Through the mean follow-up of 10 years, none of our patients have experienced lymphoma occurrence. Histopathological subtype A clearly predominated (82%). A marked eosinophilic infiltrate was present in 44% of cases and a cutaneous T-gamma clone in 40%. No correlation was observed between histopathological subtype, cutaneous clone or LyP clinical course. CONCLUSIONS: Paediatric LyP belongs to the group of CD30-positive CTLPDs including C-ALCL. Children have to be carefully followed up lifelong, even if the prognosis appears good. The high frequencies of an associated viral infection, atopic dermatitis, marked eosinophilic infiltrate and a good outcome suggest that paediatric LyP could be considered a reactional disease rather than a malignant disorder.