CASE REPORT: CAPLAN S SYNDROME IN A PATIENT WITH RHEUMATOID ARTHRITIS AND LATENT TUBERCULOSIS

Caplan syndrome, or rheumatoid pneumoconiosis, is characterized by well-defined pulmonary nodules in patients with rheumatoid arthritis (RA) and inorganic dust exposure.Typically, these patients have a history of such exposure and develop peripheral pulmonary nodules distinct from coal workers' pneumoconiosis.RA can precede or follow the discovery of nodules by up to a decade.Rheumatoid factor is often present but not always.While silicosis or coal workers' pneumoconiosis is commonly observed, they are not prerequisites for Caplan syndrome.Histological assessment is crucial due to subtle radiographic differences between rheumatoid pneumoconiosis and silicosis nodules. CASE REPORTA 69-year-old retired ceramic industry worker presented with pain, edema, and hyperemia in his hands and wrists, along with weakness.He had been diagnosed with RA 7 months prior and was on methotrexate and later leflunomide without significant improvement.Adalimumab was then initiated, but after six doses, there was no clinical improvement.It was decided to perform all the exams again at our service.Laboratory tests (2022): rheumatoid factor, 39.1; Quantiferon test, positive.Non-contrast chest computed tomography (CT) (2022): bilateral pulmonary nodules predominating in the upper lobes.Some with dense content, which may be related to the patient's RA, making it impossible to rule out the possibility of Caplan syndrome.It was decided to immediately suspend biological therapy due to the positivity of the Quantiferon test.The patient was referred for a nodule biopsy.Tomography-guided transthoracic biopsy (2022): rheumatoid-like nodule of loose collagen in concentric layers interspersed with fibroblasts and macrophages in palisades.He started treatment with isoniazid for 9 months.After 1 month of using the medication, the infectious disease specialist authorized him to restart treatment with rituximab. CONCLUSIONThis case illustrates the diagnostic complexity and therapeutic challenges of Caplan syndrome.The patient demonstrated classic features, including a significant occupational history and corresponding radiological and histopathological findings.There was good evolution and stabilization of the disease with rituximab.The use of this medication stabilizes the size of pulmonary nodules and coalescence and also prevents progression to pulmonary fibrosis.