LAUSR

Dear Editor, A 34-year-old man with a 2-year history of pulmonary opacities was admitted to our hospital. He complained of shortness of breath, cough, anorexia, night sweats, and fatigue for 2 years. Laboratory findings were shown below (Supplementary Table 1). Chest and abdomen computed tomography (CT) scans revealed pulmonary opacities and cysts in both lungs (Fig. 1), multiple enlarged lymph nodes in the axillary, mediastinum, and left supraclavicular fossa, and hepatosplenomegaly. Pathological examination of a submandibular lymph node biopsy suggested Castleman disease (CD) of the plasma cell subtype. He was diagnosed with idiopathic multicentric CD (iMCD). TCP (thalidomide 100 mg per day, cyclophosphamide 300 mg/m per week, and prednisone 1 mg/kg d1–2 per week) regimen was administered [1]. His symptoms alleviated for the first 3 months after TCP treatment but exacerbated at 6 months (Fig. 1) (Supplementary Table 1). Second-line therapy with rituximab monotherapy was initiated but was soon considered as treatment failure. Third-line BCD (bortezomib 1.3 mg/m per week, dexamethasone 40 mg per week, cyclophosphamide 300 mg/m per week) was then started and the patient was free from fever, weight loss, anorexia, and fatigue. His ESR and CRP decreased significantly while albumin, hemoglobin, and creatinine levels were normal (Supplementary Table 1). Multiple enlarged lymph nodes in the axillary, mediastinum, and left supraclavicular fossa became smaller. A partial response (PR) was achieved for 1 year with BCD treatment [2]. However, despite the treatment response, his pulmonary cysts and opacities were not improved (yet not exacerbated) (Fig. 1). CD presents with unicentric (unicentric CD, UCD) and multicentric regions (multicentric CD, MCD) of lymph node enlargement. For MCD, some are caused by human herpesvirus-8 (HHV-8) whereas others are HHV-8–negative/idiopathic(iMCD) [2]. CD-associated diffuse parenchymal lung disease (DPLD) is rare and not well reported, with a spectrum of presentations including nodules or masses, ground glass opacities, patchy consolidation, interlobular septal thickening, and peribronchovascular thickening [3]. Cysts are rarely seen [4]. Diffuse cystic lung diseases (DCLDs) are characterized by multiple irregularly shaped and thin-walled spaces and inflammatory or infiltrative processes resulting in irreversible lung remodeling including displacement, destruction, replacement of alveolar septa, distal airways, and small vessels [5]. The underlying etiologies are complex but the lung cysts are generally considered irreversible [5]. Evaluation of treatment response for iMCD could be complex; the most widely accepted criteria include biochemical assessments (hemoglobin, CRP, albumin, and creatinine) and lymph node and symptom evaluation [2]. However, it is still unknown whether improvement of lung cysts should be set as a treatment target according to the current criteria [2]. Though our patient achieved partial response, his Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00277-020-04030-5) contains supplementary material, which is available to authorized users.