Solitary mast cell tumor of the lung

An extremely rare solitary mast cell tumor of the lung was studied histologically, immunohistochemically, and ultrastructurally. The histologic features of the tumor included nodular growth of well-differentiated mast cells and clear cells with no granules. The current case is the third case of a solitary mast cell tumor (granuloma) of the lung in the literature. Clinicopathologic features of this tumor are compared with the other two cases reported previously in the international literature, and the nature of the clear cells is discussed.