Malignant pulmonary lymphoproliferative angiitis. A monoclonal neoplasm.

A 55-year-old female developed a rapidly fatal, infiltrative, bilateral pulmonary disease. Open lung biopsy and subsequent autopsy revealed diffuse involvement by a malignant lymphoproliferative condition showing a striking angiocentric and angioinvasive pattern. This feature, together with microscopic involvement of hilar lymph nodes, bone marrow, spleen, and other viscera suggested lymphomatous transformation of lymphomatoid granulomatosis (LYG). The paucity of necrosis and of the typical polymorphic infiltrate was at variance with the classical description of that condition; however, the bilaterality of the process and the distinctive angioinvasive growth pattern were unlike the typical primary pulmonary lymphoma. Plasmacytoid cells were observed both by light and electron microscopy. Immunohistochemicl evaluation characterized this disease as a monoclonal lymphoproliferative malignancy.