(Adenochondroma, pulmonary mesenchymoma) This entity is probably a neoplasm rather than a hamartoma. It may be either endobronchial or, more commonly, parenchymal.
The incidence in a series of 8000 post-mortems was 0.25%. The average age is 55 years. Endobronchial lesions more commonly occur in men. Cytogenetic abnormalities are common, indicating that this is probably a true neoplasm.
These lesions are usually asymptomatic, but may present with haemoptysis. Multiple bronchial hamartomas have been reported. In a series from Finland, the incidence was higher in smokers. Carney's triad consists of gastric epithelioid leiomyosarcoma, pulmonary chondroma and functioning extra-adrenal paraganglioma: the syndrome is usually seen in women below the age of 35 years.
The tumours form homogenous peripheral round or lobulated opacities. Calcification is variable.
Endobronchial lesions are sessile or pedunculated. The cut surface is grey, or yellow if there is much fat. Parenchymal lesions are often sub-pleural and may show cystic foci.
These lesions consist of a combination of epithelium and connective tissue. In the endobronchial lesions, the epithelium lines cleft and is usually of ciliated columnar type: seromucinous glands may be present. In parenchymal lesions, it is usually non-ciliated. There are foci of cartilage merging with loose myxoid tissue, bone (with marrow), fibrosis, fat, smooth muscle and lymphoid tissue. The parenchymal lesions show more cartilage and less fat. Non-caseating granulomata have been reported, without evidence of micro-organisms or sarcoid.
Fibroma
Bronchial lipoma
Metastatic teratoma after chemotherapy
Malignant change has been reported, albeit extremely rarely.
1 Gjevre JA, Myers JL,Prakash UB Pulmonary hamartomas. Mayo Clin Proc 1996; 71:14-20
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