[Auto-immune diseases and cancers. Second part: auto-immune diseases complicating cancers and their treatment].

Autoimmune diseases may reveal or occur during the course of a neoplasia or its treatment. Autoimmune cytopenia, especially haemolytic anaemia, is common in lymphoproliferative disorders such as chronic lymphoid leukemia. The link between cancer and myositis is well established. Dermatomyositis is associated with an increased relative risk of cancer of 3.4 to 4.4. A combination of detection of antibodies against p155 and TEP-computed tomography may be the best approach to ascertain the presence of occult malignancy in patients with dermatomyositis. A cutaneous or a systemic vascularitis may reveal a cancer, most often a haematological malignancy such as hairy cell leukemia. Paraneoplastic polyarthritis have been described in particular with adenocardinoma of the lungs. Underlying neoplasia should be considered in male smokers patients with new onset polyarthritis and poor health status. The prevalence of autoimmune conditions in myelodysplastic syndromes is 10 to 30%. Vasculitis and relapsing polychondritis are the most commonly reported manifestations. Immune manifestations can also be related to treatment. The most common treatment complications are autoimmune haemolytic anaemia with fludarabine and thyroiditis related to interferon and cervical radiotherapy.