Obstruction of the pulmonary artery by granulomatous vasculitis: a clinical, morphological, and immunological analysis.

The case of a 45 year old woman presenting with fever of unknown origin, headache, polyarthralgia, and chest pain is described. Computed tomography scans and angiography disclosed a mediastinal tumour with a complete obstruction of the right pulmonary artery, positron emission tomography scans showed a tracer accumulation in the walls of the pulmonary artery and the aorta. Thoracotomy was performed and subsequent histological analysis of multiple biopsy specimens led to the diagnosis of a form of giant cell arteritis of the pulmonary artery. Immunological analysis of the cytokine profile of peripheral blood mononuclear cells (PBMC) showed a markedly increased production of tumour necrosis factor α (TNFα) and interleukin 2 (IL2) and a normalisation of TNFα production after successful treatment. In contrast, the production of interferon γ, IL4, IL6, IL10, and IL13 was normal. Furthermore, an expanded subset of double positive CD4+/CD8+ T cells was remarkable, as well as an increased expression of the IL2 receptor on PBMC. Immunomodulatory treatment with steroids and methotrexate was started and led to a rapid resolution of symptoms and morphological changes. The right pulmonary artery, however, remained occluded. The particular features of this case are reviewed with consideration of its clinical, diagnostic, histopathological, and immunological characteristics and are compared with other reported findings.