[Lymphocytic infiltrate of the dermis preceding typical Sweet's syndrome].

Background: The histologic criteria for Sweet's syndrome consist in prominent oedema of the dermis and a diffuse infiltrate of numerous neutrophils with leukocytoclasis without vasculitis in the superficial and the deep dermis. Several comorbidities have been observed in patients with Sweet's syndrome, particularly hemo-proliferative diseases.

Patients: We report the cases of two men aged 60 and 75 years with Sweet's syndrome associated in one case with myelodysplasia and in the other with chronic lymphocytic leukemia. These two patients had typical edematous plaques highly evocative of Sweet's syndrome. However, histological examination revealed superficial and deep perivascular lymphocytic infiltrate in the dermis on 5 occasions before the typical neutrophilic dermatosis of Sweet's could be diagnosed after respectively 2 and 4 years of progression.

Discussion: Histological findings in Sweet's syndrome are characteristic and constitute a major diagnostic factor. However, these two cases show that a lymphocytic infiltrate can occur months or even years before the appearance of typical neutrophilic infiltrate in patients with Sweet's syndrome.