Chloroma (aleukaemic leukaemia cutis) initially diagnosed as cutaneous lymphoma

A 65-year-old man presented in 1997 with a nodule on his back; histology showed apparent high grade T-cell lymphoma, treated after excision with radiotherapy. He relapsed with lesions on the thigh and buttock in 1998 and was treated with CHOP chemotherapy with a complete response. Further relapse occurred in 1999 with a nodule on his thigh again; he received CNOP (doxorubicin substituted with mitozantrone). At no stage was there clinical, bone marrow or radiological evidence of extra cutaneous disease. In November 2000 he presented with widespread indurated plaques and violaceous nodules. Biopsies repeated with extensive immunohistological staining diagnosed aleukaemic leukaemia cutis. Our patient was diagnosed with cutaneous T-cell lymphoma (CTCL) on the basis of clinical and haemotoxylin & eosin appearances. The correct diagnosis was made after extensive immunohistological studies (including myeloid markers) of repeat biopsies. This case illustrates the importance of diagnostic review in atypical CTCL. There is a high incidence of progression to acute myeloid leukaemia.