Central nervous system relapse in a pediatric anaplastic large cell lymphoma patient with CLTC/ALK translocation...

The aberrant expression of the anaplastic lymphoma kinase (ALK) gene in ALK-positive (ALK+) anaplastic large cell lymphoma (ALCL) is usually due to t(2;5)/NPM-ALK. However, rarely, aberrant ALK expression can also result from a rearrangement of the ALK gene with various partner genes. Central nervous system (CNS) metastasis is very rare in ALK+ALCL. Patients with CNS involvement show an inferior prognosis.

Here, we present the case of an 8-year-old girl diagnosed with ALK+ALCL. She presented with fever, skin nodules, leg swelling, and abdominal pain over the preceding 6 mo. She had extensive involvement and showed an extraordinary rare translocation, t(2;17)/CLTC-ALK, as demonstrated by RNA-seq. She underwent chemotherapy as per ALCL99, followed by vinblastine (VBL) maintenance treatment, and achieved complete remission. However, she developed CNS relapse during VBL monotherapy. The patient achieved a durable second remission with high-dose chemotherapy (including methotrexate 8 g/m²) and continuous treatment with alectinib and VBL.

Alectinib showed significant and durable CNS effects in this patient. However, more cases are needed to prove the efficacy and safety of alectinib for pediatric ALK+ALCL patients.