Question category: Gastroenterology
A 50 year old gentleman presents with intermittent diarrhoea and bloating. He has some associated anorexia and weight loss. On further questioning he also admits to having intermittent pains in his joints and a chronic cough. On examination his abdomen is soft and non tender but there is evidence of lymph node in his axilla, supraclavicular and groin regions. His bloods reveal a low haemoglobin and albumin. A small bowel biopsy is performed and shows expanded villi with PAS positive macrophages. What is the most likely diagnosis?