Methods We describe a 17 yo female patient with Behcet’s syndrome and CD. She was affected by a 4-month history of severe oral and genital ulcers, bilateral uveitis and abdominal pain. A CT scan of the abdomen showed the presence of a retroperitoneal mass (9,4 x 9,0 x 7,4 cm). On the basis of histological and immunohistological findings, a diagnosis of CD, hyaline vascular type, was formulated. There was no lymphadenopathy, fever or anemia. One month later, oral ulcers turned into desquamative plaques, Nikolsky sign was observed and an oral biopsy diagnosed paraneoplastic pemphigus. Ca 125 and Ca 199 levels were elevated. The patient developed an acute pleuritic pain with dyspnea, image exams revealed pneumomediastinum, pneumothorax and subcutaneous emphysema, and a bronchoscopy revealed a tracheal lesion suggestive of pemphigus. No signs of infection were present and pulses of methylprednisolone were prescribed, with good initial response. After the surgical excision of the retroperitoneal mass (June, 2010), she developed progressive dyspnea and a pulmonary function test revealed a mixed respiratory disorder. A thoracic CT scan showed patchy areas of ground-glass opacity. Thromboembolism was excluded. She was treated with high doses of prednisolone, colchicines, cyclosporine 200mg/day, with no response. Extensive mucosal erosions were still present, the tumor markers kept on rising and she presented a severe pulmonary restriction. We decided to initiate Tocilizumab EOW associated with moderate dose of prednisone.