Sweet syndrome: long-term follow-up of 138 patients.

BACKGROUND: Several studies support a strong association of Sweet syndrome (SS) with malignancy. However, only a few studies analysing the clinical features of malignancy-associated SS have been published in recent years.

AIM: To retrospectively study the clinical features of SS that could predict the development of associated malignancies and to analyse the development of malignant neoplasia during long-term follow-up of patients with SS.

METHODS: Clinical features of the patients diagnosed with SS syndrome between 1987 and 2013 at Bellvitge Hospital (Barcelona, Spain) were retrospectively analysed.

RESULTS: In total, 138 patients were included in the study (66 male, 72 female, mean ± SD age 51.24 ± 14.11 years). SS was associated with haematological malignancy in 31 cases, infection in 23, inflammatory bowel disease in 12, inflammatory systemic disease in 8, and solid tumours in 4. It was drug-induced in 5 cases and idiopathic in 54. In four patients, an underlying haematological disease that was considered related to SS was diagnosed between 4 and 16 months after SS presentation. Variables significantly associated with malignancy in multivariate logistic regression analysis were age (OR = 1.08 for each increasing year, P = 0.01), anaemia (OR = 9.38, P = 0.001), thrombocytopenia (OR = 16.10, P < 0.01) and absence of arthralgia (OR = 11.13, P < 0.01).

CONCLUSIONS: Patients with older age, anaemia or thrombocytopenia, and without arthralgia are more likely to have malignancy-associated SS. We recommend that patients with SS without clear aetiology should be followed up for at least 16 months to exclude a possible underlying haematological malignancy.