A recent case that had been referred to our center as possible T-PLL was in a patient with marked erythroderma and a relatively modest lymphocytosis, in this case the weak CD7 positivity pushed the referring center to this diagnosis, however, the clinical history of the erythroderma being significant for many years and the discrepancy of the extent of cutaneous involvement and progression with lack of progression of the leukemic component made the diagnosis of T-PLL very unlikely. This evidence concerns the gene CD7 and exfoliative dermatitis.