PRF1 and subcutaneous panniculitis-like T-cell lymphoma: According to the 2016 World Health Organization (WHO) and 2018 World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification, SPTCL is defined as subcutaneous lymphomas with an α/β T cell phenotype and neoplastic T cells expressing CD3, CD8, and cytotoxic proteins (GZMB, TIA-1, perforin) (1, 2).