Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cancer and it is widely regarded as being distinct from the other subtypes of peripheral T-cell lymphoma. SPTCL commonly presents with subcutaneous nodules that resembles panniculitis. The clinicopathologic features of SPTCL have recently been described. However, only a few cases with their CT and sonographic findings have been reported in the radiologic literature. We illustrate here the MR findings of this rare tumor in one case that presented with a popliteal mass.