Sweet syndrome in multiple myeloma: a series of six cases

Background: Sweet syndrome (SS), a paraneoplastic syndrome characterized by fever, neutrophilia, multiple erythematous painful plaques, and a dense dermal neutrophilic infiltration, has a known association with hematologic malignancies such as acute myelogenous leukemia. However, no clear association with multiple myeloma (MM) has been reported. Materials and methods: Pathology reports of the 2357 patients with multiple myeloma at the University of Arkansas for Medical Sciences were reviewed to retrieve cases who had developed SS. Cytogenetic studies and immunoglobulin secretory status were retrieved. Five cases of SS in MM and 25 cases of SS in patients without MM underwent syndecan-1 immunohistochemistry. Observations: Six cases of SS occurring in the setting of MM showed a predominance in patients secreting IgG paraprotein. Five of the six patients received granulocyte-colony stimulating factor while the sixth received granulocyte-monocyte-colony stimulating factor. Fifty percent showed a non-specific cytogenetic anomaly. Conclusions: There is no specific cytogenetic anomaly associated with SS in the setting of MM. This paraneoplastic syndrome may be secondary to elevated levels of granulocyte colony stimulating factor (G-CSF), possibly with a component of enhanced sensitivity to endogenous G-CSF. The immunoglobulin secretory status parallels that seen in MM with cutaneous involvement, but IgG secretors may be at an increased risk of developing SS compared with their counterparts who secrete other immunoglobulins.