[Acute neutrophilic dermatosis (pustular dermatitis) associated with aggressive transformed mycosis fungoides].

BACKGROUND: Large-cell transformation in mycosis fungoides [MF] is associated with an aggressive clinical course and poor survival. In addition to tumour progression, infectious complications may be the cause of death. We report a case of aseptic pustular dermatosis in transformed MF that very quickly became aggressive and was followed by rapid death of the patient. PATIENTS AND METHODS: A 47-year-old man presented with disseminated CD30+ transformed MF skin tumours refractory to chemotherapy for nine consecutive months. Ten days after a first course of dexamethasone, cytarabine and carboplatin, he was hospitalized for febrile neutropenia. Following this episode of neutropenia, he developed a febrile pustular rash disseminated on the tumours and on plaques, associated with marked neutrophilic leucocytosis. Bacteriological and mycological skin and blood samples were negative. Tumour biopsies showed a dermal infiltrate of CD30+ T-cells corresponding to the transformed MF, mixed with neutrophils. The pustule biopsies revealed intra-epidermal pustules and dermal-epidermal infiltration of neutrophils. The pustular eruption regressed with corticosteroids. Despite a last line of treatment with romidepsin, the patient died 6 weeks after the "neutrophilic" event. DISCUSSION: Episodes of neutrophilic dermatosis [ND] are frequently seen in haematological disease and some substances can induce a variant form of eccrine hidradenitis. However, our patient's presentation was different, without the appearance of "classic" ND but rather diffuse pustular lesions carrying a poor prognosis, which was followed by rapid death. Once the hypothesis of infectious complications has been ruled out, treatment is based on systemic corticosteroids associated with specific treatment of the lymphoma.