Four Cases of Intrapulmonary Hamartoma: An ultrastructural study

Chun, Ho Jong; Kee, Keun Hong; Suh, Chae Hong; Sohn, Jang Sihn; Chi, Chung Hee

Abstract

Tumors of the lung and bronchi containing cartilage were known by a variety of names, chondroma, adenochondroma, chondromatous hamartoma and mixed tumor. This variation in nomenclatures explain the difference of illustration on the nature of these tumor. The concept pulmonary harmatomas are benign neoplasm and not developmental malformations, has gained wide acceptance in recent years. We have experienced four cases of intrapulmonary hamartoma which were all discovered during routine chest film check up for certificate of health and evaluation of other disease. One case is added further detailed histologic examination by electron microscopy. The age at time of the detection were 53 (male), 23 (male), 39 (female), and 56 (female) years old. The mean size is 4.3x3.7x3.4 cm. The locations were three left upper lobes and one right upper lobe. Lobectomy and wedge resecions were done. Cut surface showed promiment lobular structures, papillary configuration and multiple cleft like spaces. Predominant cellular components were cartilage but fat tissue in one of the four cases. Microscopic findings showed abundant hyaline cartilages bearing lobular configuration and overlying pseudostratified ciliated columnar and cuboidal epithelium. Fibromyxoid and undifferentiated cells were seen in myxoid and fatty tissue. Electron microscopic findings revealed stellate, undifferentiated mesenchymal cells bearing collagen formation, stellate smooth muscle and transition areas between undifferentiated mesenchymal cells and mature cartilage. Epithelial components were similar to terminal bronchiole and alveolar epithelium. These findings suggest the concept that intrapulmonary hamartoma represent a histologic specturm of benign mesenchymal neoplasms, which originate in peribronchial connective tissue.