Granulomatous vasculitides of the lung: a clinicopathologic approach to diagnosis and treatment.

The granulomatous vasculitides of the lung are uncommon. Overlap of their clinical and histopathologic features may create a confusing picture for the clinician and pathologist. This confusion is of concern because therapy differs depending on the exact diagnosis, with concomitant variations in associated drug toxicity. An integrated clinical and pathologic approach must be used to arrive at a prompt and accurate diagnosis. The true granulomatous vasculitides, a group that includes Wegener's granulomatosis, allergic granulomatosis and angiitis (Churg-Strauss syndrome), and necrotizing sarcoid granulomatosis, have various degrees of systemic involvement. Therapy is mainly immunosuppressive, and prognosis is generally good. The lymphoproliferative granulomatous vasculitides, which include benign lymphocytic angiitis and granulomatosis, lymphomatoid granulomatosis, and malignant lymphoma with angioinvasion, are progressively abnormal lymphoproliferative processes. Therapy may require combination chemotherapy, and prognosis is often poor.