Chondroma. Light micrograph (LM) of a section through a chondroma from the lung. Chondroma is a benign tumour, originating in chondrocytes. It is common in long bone, but more rarely occurs in the lung parenchyma. Pulmonary chondroma is often originated from ectopic cartilage of lung tissue during embryonic development. Surgical resection is the preferred treatment for pulmonary chondroma. Magnification: x 100 when printed at 10 centimetres high.