Interstitial lung disease and lymphoproliferative disease in the form of diffuse large B-cell lymphoma: 3 case reportsA case series described 3 patients (2 women and 1 man) aged 42-75 years, who developed interstitial lung disease or lymphoproliferative disease (LPD) in the form of diffuse large B-cell lymphoma (DLBCL) during treatment with methotrexate for rheumatoid arthritis (RA) or psoriasis [routes not stated; not all dosages stated].Case 1 (a 75-year-old woman): The woman, who had RA, presented to hospital with myalgia. She had been receiving methotrexate 10mg for 11 years and sulfasalazine [salazosulfapyridine] for 3 years. On presentation, no fever or significant findings were noted. Physical examination showed no abnormalities apart from ulnar deviation. No crackles were heard. Laboratory data revealed increased soluble interleukin-2 receptor. A chest CT scan revealed a nodule in her left lower lobe, which had grown dramatically in 3 months. A new nodule was also observed in the right lower lobe. Fluorodeoxyglucose (FDG)/positron emission tomography (PET)/CT revealed slight FDG uptake in the left lower lobe nodule. A much higher uptake was noted in the same lesion, in the new nodule, which developed after 3 months and in the cervical and axillary lymph nodes. Trans-bronchial lung biopsy was performed. Due to the appearance of new lesions, growth of the nodules and high FDG uptake on FDG PET/CT, methotrexateassociated LPD was suspected. Immuno-pathological examination demonstrated diffusely distributed CD20-positive lymphoid cells, some of which were also Epstein-Barr encoding region (EBER)-positive. She was also found to have some CD3-positive cells. Based on these findings, a diagnosis of LPD in the form of DLBCL was made. Hence, methotrexate was stopped, resulting in the spontaneous regression of lung lesions within months. No recurrence was observed for more than 2 years.Case 2 (a 63-year-old woman): The woman, who had RA and had been receiving treatment with methotrexate for 8 years, started experiencing appetite loss and malaise. Laboratory data revealed increased soluble interleukin-2 receptor and increased LDH. A chest CT scan showed bilateral homogeneous expanding consolidations. Interstitial pneumonia secondary to RA was considered. FDG/PET/CT revealed higher than expected FDG uptake for interstitial lung disease of RA in the same regions and in the mediastinal lymph nodes. Consolidation worsened over subsequent weeks. Therefore, she underwent trans-bronchial lung biopsy, which was consistent with a diagnosis of LPD in the form of DLBCL. EBER was negative. Hence, methotrexate therapy was stopped, resulting in the spontaneous regression of lung lesions within months. No recurrence was observed for more than 2 years.Case 3 (a 42-year-old man): The man, who had psoriasis, had been receiving methotrexate for 16 years. He subsequently presented to hospital due to cough and fever [aetiology unknown]. Laboratory data revealed slightly increased carcinoembryonic antigen and soluble interleukin-2 recepto...
