Subcutaneous sarcoidosis: Is it a specific subset of cutaneous sarcoidosis frequently associated with systemic disease?

Background: Skin is involved in 25% of cases of sarcoidosis. The lesions are specific and nonspecific depending on the presence or absence of granulomas, respectively. Specific lesions are not thought to have prognostic significance and are not associated with systemic disease. Objective: We sought to evaluate for the presence or absence of systemic disease in patients with subcutaneous sarcoidosis. Methods: With diagnostic criteria of subcutaneous sarcoidosis, 33 cases were identified in the literature and 21 cases in our institutional database. A retrospective clinical and pathologic review of these cases was conducted. Results: Subcutaneous sarcoidosis is characterized by a peak incidence during the fourth decade; female predisposition; asymptomatic to slightly tender lesions typically involving the upper extremities; cutaneous lesional clustering and multiplicity; autoimmune disease associations at time of diagnosis in a subset of cases; systemic disease associations at diagnosis in most patients, typically consisting of bilateral hilar adenopathy; and a favorable response to oral corticosteroid therapy. Limitations: Retrospective analysis with inadequate documentation of therapeutic regimens and their responses in some cases is a limitation of this study. Conclusions: The confirmatory diagnosis of subcutaneous sarcoidosis depends on identifying pannicular noninfectious sarcoidal or epithelioid granulomas with minimal lymphocytic inflammation. Subcutaneous sarcoidosis is the only specific subset of cutaneous sarcoidosis frequently associated with systemic disease.