[Lymphomatoid papulosis in children: report of 9 cases and review of the literature]

Background Lymphomatoid papulosis is a rare CD30+ T-cell lymphoproliferative disease with an excellent prognosis. It is usually seen in adults and is rare in children. The clinical and pathologic manifestations and the risk of progression to other types of lymphoma are thus not clearly defined in the pediatric age group. Objective To describe the characteristics of lymphomatoid papulosis in a group of children and perform a review of the literature. Patients and methods A retrospective study was performed of 9 patients under 18 years of age diagnosed with lymphomatoid papulosis and treated in our department between 1995 and 2009 Results The study included 7 boys and 2 girls aged between 2 and 17 years. Lesions compatible with pityriasis lichenoides acuta appeared before the lymphomatoid papulosis in 2 cases and afterwards in 1 case. The lymphomatoid papulosis lesions resolved spontaneously, leaving postinflammatory hyperpigmentation (77%) or hypopigmentation (23%). Scarring occurred in 77% of cases. Histologically, all cases showed features compatible with lymphomatoid papulosis type A. Molecular studies showed monoclonality in all 3 cases in which this technique was performed. Conclusions Lymphomatoid papulosis is a rare disease in childhood and the manifestations are similar to the adult form. This lymphoproliferative disease, occasionally associated with pityriasis lichenoides acuta, has histological features compatible with a type A or histiocytoid pattern. Progression to other lymphoproliferative disorders during followup is less common in the childhood form than in adults. The frequent association of pityriasis lichenoides acuta and lymphomatoid papulosis observed in our study, and the difficulty distinguishing between these 2 conditions in some cases, suggest that these diseases could be part of a single clinical-pathological spectrum.