Lupus erythematosus tumidus in a patient with mycosis fungoides stage IB after complete response to PUVA.

Diagnosis of mycosis fungoides (MF), the most common form of cutaneous T-cell lymphoma (CTCL), can be challenging given the overlapping clinical and pathologic features with various other conditions. High-throughput TCR sequencing (HT-TCRseq) has an outstanding capacity to facilitate diagnosis of CTCL1 , identify aggressive forms of MF in early-stage2 , and associate burden of malignant cells with response to PUVA treatment3 .