Systemic lupus erythematosus associated with thymoma: A fifteen-year observational study in France.

Objective: To describe the clinical, biological and pathological characteristics of patients with the association of SLE and thymic epithelial tumors (TET) in a retrospective multicenter series.

Methods: Cases diagnosed in France between 2000 and 2015 were collected after a call for observations from the French network for thymic epithelial tumors (RYTHMIC database) and the French National Society of Internal Medicine (SNFMI).

Results: Fourteen patients were identified, the majority were women (93%). The median age at diagnosis of lupus was 43.5 [range: 30-66] years and 43.5 [range: 26-73] years at diagnosis of thymoma. TET required chemotherapy and/or radiotherapy complementary to surgery in >90% cases. Lupus was diagnosed before, simultaneously, or after diagnosis of thymoma in 6, 3 and 5 cases, respectively. Among the lupus manifestations, joint involvement was predominant (78.6%), followed by autoimmune cytopenia (35.7%), cutaneous affections (28.6%), serositis (28.6%) and renal involvement (21.4%). SLE was associated with one or more AID in 5/14 patients. These characteristics were compared with those from 17 patients identified in the literature. Among them, joint and skin involvement as well as pleural/pericardial effusions occurred in >50%. SLE was controlled by prednisone and hydroxychloroquine in the majority of cases, but 7 out of 31 patients had an immunosuppressant.

Conclusion: The association of SLE and TET is rare, and its clinical profile seems to be distinguished by the frequency of cytopenias. The management of these patients is complicated by the need to treat cancer, lupus and/or associated autoimmune diseases.