INTRAVASCULAR BRONCHIOLOALVEOLAR TUMOR: Report of An Autopsy Case and Review of Literature

An autopsy case with intravascular bronchioloalveolar tumor occurring in a 51‐year‐old Japanese woman is reported. The lungs contained multiple nodules which were characteristic features of this tumor. In addition, the tumor diffusely involved bilateral lower lobes associated with extensive pleural invasion. and the tumor tended to spread along vascular and bronchial trees. No extrathoracic metastasis was noted. Histologically, the nodules showed hypocellular hyaline or myxoid tissue surrounded by peripheral cellular layers. Diffuse consolidated areas were composed of collagenous connective tissue with scattered tumor cells. Factor VIII‐related antigen could not be demonstrated in tumor cells, but the negative result was considered to be secondary to antigen deterioration by delayed fixation of the tissue. Electron microscopic examination did not support the alveolar epithelial cell origin, but revealed morphological characteristics of myofibroblasts and endothelial cells. The tumor is presumed to be derived from vascular stem cell with a tendency of endothelial differentiation. ACTA PATHOL. JPN. 35 : 631–642, 1985.