A rare cause of B-symptoms and polyarthritis

A 39-year-old male patient without any relevant medical history presented with 15 kg involuntary weight loss and night sweats for 2 months. He mentioned one episode of evening fever, altered consistency of stools and a dry cough that appeared since one year. Clinically there was a cachectic man without palpable adenopathies, nor organomegaly. The patient developed a synovitis of the left shoulder and right knee. Furthermore, tenosynovitis of all finger flexor tendons was seen. Blood tests revealed a progressive hypochromic microcytic anemia with thrombocytosis and elevated CRP 75 μg/l (normal range <5 μg/l). The ferritin was inflammatory elevated, yet the transferrin saturation also indicated iron deficiency. The family doctor referred the patient to a hematologist. A positron emission tomography and computed tomography scan showed adenopathy retroperitoneally, diffuse mesenteric and axillary bilateral. Because of ongoing weight loss and cachexia despite normal intake, the patient was admitted to the hospital for total parenteral nutrition and endoscopic evaluation