Background: Ki-1 (CD30) ALCL is a rare and distinct type of high-grade NHL. A relevant feature is young age at presentation. Most reported pediatric series are retrospective analyses of heterogeneously-treated cases.
Patients and methods: Between 1976 and 1993, Ki-1 ALCL was diagnosed in 32 children (20 males 12 females; median age 9 years; 10.4% of childhood NHL). Before 1987, original diagnoses had been malignant histiocytosis in 14 cases, and immunoblastic NHL in 2. The treatment program for childhood T-lymphoblastic NHL, except for CNS prophylaxis, was applied in 28/32 cases. Radiotherapy to involved sites not in complete remission within 4 weeks after treatment start was used only prior to 1987.
Results: In 78% of cases, Ki-1 ALCL presented in skin, bone, spleen and lung. Lymph nodes were frequently involved, often in association with periadenitis. Bone marrow and spinal fluid were negative in all cases. Eleven patients were classified as stage I/II, 21 as stage III. Fewer was present in 65% of patients. Cell phenotype was T in 21/32, and null in the remaining 11. Treatment results were evaluable in 27/32 children, all of whom achieved complete remission. Seven relapsed and 4 died of their disease. Five-year survival and progression-free survival were 84% and 72% respectively. Involvement of peripheral lymph nodes, absence of spleen, liver, lung and mediastinum involvement, and male sex were favourable indicators.
Conclusions: Ki-1 ALCL is a high-grade NHL with a relatively good prognosis when treated with multiagent intensive chemotherapy. Because of its clinical peculiarities a unique treatment approach in probably warranted.