Hematological malignancies mimicking rheumatic syndromes: case series and review of the literature.

It is well established that some rheumatic syndromes (RS) are associated with several hematological malignancies. We aimed to describe the clinical course of patients with hematological malignancies mimicking RS. We studied a series of four patients presenting with apparent RS who were eventually diagnosed with hematological malignancies, and reviewed the relevant literature. Our series consisted of 4 patients, with a mean age of 62.8 ± 20.3 years, who presented to our rheumatology unit between December 2012 and March 2018. Two patients were initially diagnosed with polyarthritis. One of these patients was eventually diagnosed with multiple myeloma and amyloidosis and the other was diagnosed with angioimmunoblastic T-cell lymphoma. The third patient was initially diagnosed with migratory arthritis and was eventually diagnosed with acute myeloid leukemia. The fourth patient was initially diagnosed with giant cell arteritis and eventually diagnosed with anaplastic large T-cell lymphoma. All the patients displayed a very good response to corticosteroid treatment. Vigilance for occult malignancy is essential in the diagnostic workup of RS. A good response to corticosteroids may constitute a major diagnostic pitfall in patients with hematological malignancies presenting with an apparent RS. In these cases, subtle clinical and laboratory features should elicit the clinician to seek for an occult malignancy.