Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is classified as an unusual subtype of peripheral T-cell lymphoma that preferentially infiltrates the subcutaneous tissue without overt lymph node involvement. SPTCL is particularly rare in children, and there have been only a few case reports describing the US and CT findings of SPTCL. To our knowledge, the use of whole-body (WB) MRI as the initial and follow-up diagnostic method to assess the extent of disease and relapse of SPTCL has not been reported in children. In our case report involving one child, WB MRI was useful as both the initial and follow-up diagnostic method to assess the extent of disease and to monitor the patient's response to therapy for SPTCL.