Histiocytoid Sweet's Syndrome in the Setting of Myelodysplastic Syndrome.

Acute febrile neutrophilic dermatosis, or Sweet's syndrome, is characterized by tender, edematous papules and plaques, favoring the upper extremities and the head and neck regions. The classic variant of Sweet's syndrome involves a predominantly neutrophilic dermal infiltrate on histopathology. However, histiocytoid Sweet's syndrome has been noted to have a primary histiocytoid mononuclear infiltrate and is typically found in patients with malignancies such as myelodysplasia. This case report discusses the treatment of histiocytoid Sweet's syndrome in an immunocompromised patient with a recent history of Mycobacterium avium complex infection and latent tuberculosis in the setting of myelodysplastic syndrome.