Introduction: Known causes of granulomatous inflammation must be excluded before the diagnosis of sarcoidosis can be secured. We explored the possibility that connective tissue diseases (CTDs) could be a cause of granulomatous inflammation through an analysis of patients cared for in 2 medical centers and a review of the medical literature.
Methods: Patients with both a diagnosis of sarcoidosis and a CTD were identified at two medical centers. In addition, a literature search identified reported cases of patients with both diagnoses.
Results: We identified 15 patients at 2 medical centers plus 53 previous reported patients in the medical literature (total=68) with diagnoses of both sarcoidosis and a CTD. The patients were predominantly female. Scleroderma was the most common CTD. Only 2/59 (3%) with chest radiographs recorded had fibrocystic (stage 4) disease. In 48/67 (72%) patients where the time of diagnosis was recorded, sarcoidosis was diagnosed simultaneously or after the CTD. Sarcoidosis in only one organ ("isolated sarcoidosis") was associated with sarcoidosis being diagnosed simultaneously or after the CTD (p=0.0001).
Conclusions: These data suggest that a significant portion of patients with CTDs and sarcoidosis may actually not have the latter disease. Rather, the CTD may "cause" granulomatous inflammation. Alternate explanations for these findings include that sarcoidosis and/or the connective tissue disease was misdiagnosed in these patients. The diagnosis of a concomitant connective tissue disease and sarcoidosis must be made with extreme caution.
Keywords: Autoimmune disease; Connective tissue disease; Diagnosis; Organ involvement; Sarcoidosis.
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