Sclerosing mediastinitis and mast cell activation syndrome.

BACKGROUND: Sclerosing mediastinitis (ScM) is a rare, potentially life-threatening disorder, idiopathic in roughly half the cases. Systemic symptoms not attributable to sclerosis often appear in idiopathic ScM. Mast cell activation disease (MCAD) is a potential cause of these symptoms and also can cause sclerosis. ScM has not previously been associated with MCAD. Presented here are the first two cases of ScM associated with MCAD, specifically mast cell activation syndrome (MCAS). CASE 1: A 58-year-old chronically polymorbid woman developed ScM following matched sibling allogeneic stem cell transplantation. Eight years later MCAS, likely underlying most of her chronic issues, was identified. CASE 2: A 30-year-old chronically polymorbid woman presented with superior vena cava syndrome and was diagnosed with ScM. On further evaluation, MCAS was identified. Treatment promptly effected symptomatic improvement; sclerosis has been stable. Non-compliance yielded symptomatic relapse; restored compliance re-achieved symptomatic remission.

CONCLUSIONS: Different MCAS presentations reflect elaboration of different mediators, some of which can induce inflammation and fibrosis. Thus, MCAS may have directly and/or indirectly driven ScM in these patients. MCAS should be considered in ScM presenting with comorbidities better explained by mast cell mediator release.