BRONCHIOLITIS DUE TO PARANEOPLASTIC PEMPHIGUS IN A PATIENT WITH CASTLEMAN DISEASE

SESSION TITLE: Diffuse Lung Disease SESSION TYPE: Med Student/Res Case Report PRESENTED ON: 10/20/2019 1:00 PM - 2:00 PM INTRODUCTION: Castleman disease is a rare lymphoproliferative disorder which has an association with paraneoplastic pemphigus (PNP). PNP is typically characterized by blistering skin and mucosal lesions. PNP patients can also develop a restrictive bronchiolitis. We present a case of bronchiolitis due to PNP in a patient with Castleman disease. CASE PRESENTATION: A 35-year old man with a two-year history of lymphopenia was diagnosed with Castleman disease after a mediastinal mass was found on chest imaging. Surgical pathology was consistent with Castleman disease. He subsequently developed new mucosal and skin lesions that were diagnosed as PNP on biopsy. He was then started on high dose steroids and referred to Pulmonology after he reported dyspnea on exertion. CT of the chest revealed air trapping. Pulmonary function testing noted restrictive pattern without reversibility to bronchodilators along with reduced DLCO. Based on these results the patient was diagnosed with bronchiolitis due to PNP, which is associated with Castleman disease. He was continued on high dose steroids and started on Rituximab. He symptomatically improved and PFTs have also shown improvement. DISCUSSION: Castleman disease is a lymphoproliferative disorder and it is sub-classified into unicentric and multicentric subtypes. Unicentric disease involves enlarged lymph nodes in one region of the body. Castleman disease can be associated with PNP which is an often fatal mucocutaneous blistering disease (1). PNP can also have pulmonary involvement; patients with this disease can develop a potentially life threatening restrictive bronchiolitis. This bronchiolitis often occurs later in the disease course and is associated with shortness of breath that is out of proportion to changes seen on imaging. Pulmonary function testing often shows an obstructive pattern and CT scans may show various degrees of air trapping (2). The exact cause of pulmonary damage is unknown although inflammatory infiltrates and antibody deposits have been detected in pulmonary epithelium in PNP patients (3). Due to the uncommon nature of this disease no therapeutic randomized controlled trials have been performed. High dose systemic glucocorticoids are often the initial treatment. Ritxuimab therapy for PNP has also been described with the response being variable. Plasmapheresis, IVIG and cyclophosphamide have also been used in conjunction with other therapies. CONCLUSIONS: The pulmonary manifestations of PNP can be life life threatening and it is important to recognize this as a potential cause of shortness of breath in patients with Castleman disease. When a patient is suspected of having this disease workup should include chest imaging such as a CT scan and pulmonary function testing. The treatment for these patients is poorly defined due to lack of randomized controlled trials but it often includes high dose glucocorticoids. Reference #1: Anhalt GJ, Kim SC, et al. Paraneoplastic pemphigus. An autoimmune mucocutaneous disease associated with neoplasia. New Eng J of Med 1990; 323(25):1729. Reference #2: Maldadono F et al. Constrictive bronchiolitis associated with paraneoplastic autoimmune multi-organ syndrome. Respirology. 2009 Jan;14(1):129-33. Reference #3: The mechanism of respiratory failure in paraneoplastic pemphigus.Nousari HC, Deterding R, Wojtczack H, Aho S, Uitto J, Hashimoto T, Anhalt GJ N Engl J Med. 1999;340(18):1406. DISCLOSURES: No relevant relationships by Mollie Brittan, source=Web Response No relevant relationships by Daniel Hershberger, source=Web Response