Pulmonary chondroma: a tumor associated with Carney triad and different from pulmonary hamartoma

The Carney triad is the clinical association of gastric stromal sarcomas, pulmonary cartilaginous tumors, and extra-adrenal paragangliomas. The pulmonary tumors are its second commonest component and have been misinterpreted clinically and pathologically as metastases from the gastric tumors and pulmonary cartilaginous hamartomas, respectively. They have not been previously described in detail in the pathology literature or compared with pulmonary cartilaginous hamartomas. Forty-two patients with pulmonary cartilaginous tumors as a component of Carney triad were identified. Clinical, radiographic, and pathologic findings in the cases were tabulated. Hematoxylin and eosin-stained sections of the neoplasms were evaluated for a series of histologic features. A subgroup of 41 tumors from the latter was compared with those in a group of pulmonary cartilaginous hamartomas. Patients with Carney triad group were predominantly young women. Their pulmonary neoplasm(s) were usually asymptomatic, often multiple, well circumscribed, medium-sized (mean diameter=2.8 cm), and composed almost exclusively of cartilage and bone surrounded by a fibrous pseudocapsule. The cartilage was usually myxoid, less frequently hyaline, and commonly calcified, ossified, or both. They showed no fat, smooth muscle or entrapped respiratory epithelium, tissues that were common in pulmonary hamartoma (P<0.0001). None of the tumors metastasized or was fatal. The pulmonary neoplasms in the Carney triad are well-differentiated benign cartilaginous tumors that are best designated as chondromas. They differ pathologically from pulmonary cartilaginous hamartomas on the basis of the presence of a thin fibrous pseudocapsule, frequent bone metaplasia, and calcification, and also the absence of entrapped epithelium and fat.