This rare, leukemic form of cutaneous T-cell lymphoma (CTCL) is also known as the Sézary syndrome. It is a rare but aggressive lymphoma characterised by erythroderma, lymphadenopathy and atypical lymphocytes (Sézary cells). These lymphocytes are characterised by a brain-shaped, folded nucleus. This nucleus shape is very similar to the nucleus seen in promonocytes.