Coexistence of Systemic Sclerosis and Sarcoidosis in a Silica-Exposed Patient: Clinical Insights and Literature Review

Background Systemic sclerosis (SSc) and sarcoidosis are distinct autoimmune diseases with overlapping clinical features, and their coexistence is rare. Both diseases share pathophysiological mechanisms that can be influenced by environmental factors, such as silica exposure, which may contribute to more aggressive forms of systemic sclerosis and increased prevalence of sarcoidosis. Case Presentation We, herein, present the case of a 38-year-old Brazilian male exposed to silica and diagnosed with an overlap syndrome of systemic sclerosis and pulmonary sarcoidosis, and treatment with mycophenolate mofetil and prednisone was initiated. Despite initial improvement, disease recurrence occurred during steroid tapering, leading to the addition of rituximab. Over time, the patient showed substantial clinical improvement, with normalization of inflammatory markers and return to normal activities. Discussion The association between systemic sclerosis (SSc) and sarcoidosis involves complex immunopathological, environmental, and genetic interactions that trigger similar autoimmune responses. In SSc, silica activates the innate immune system, disrupting immune tolerance and promoting autoantibody production and tissue damage. In sarcoidosis, silica is frequently found in granulomas, suggesting its direct role in the disease's pathogenesis. Conclusion This case has highlighted the complexity of diagnosing and managing overlap syndromes, particularly when environmental exposures are involved, and emphasized the importance of a comprehensive diagnostic approach to guide treatment decisions.