Chondromas are benign tumours that originate from chondrocytes. Chondromas are typically found in the long bones and rarely arise in the lung parenchyma, with pulmonary chondroma only accounting for 0.04% of lung tumours [
This study was approved by the institutional Medical Ethics Committee. Between May 2006 and January 2017, five female and three male patients (age range: 45–73 years, mean age: 55.6 years) with pathologically proven pulmonary chondroma were retrospectively analysed. All eight patients had undergone surgery for the disease. Four of the eight patients exhibited a cough, two of whom showed haemoptysis and shortness of breath, one patient exhibited chest pain as the predominant symptom, and three patients had no clinical symptoms.
CT was performed using a 16-slice to 128-slice multidetector (GE light speed 16 slice; GE bright speed 16 slice; Somatom Sensation 64 slice; Discovery CT 750 HD 128 slice). Seven patients underwent plain axial CT scanning using a soft tissue algorithm. CT images were acquired in the arterial (25–30 s after injection) and venous (50–60 s after injection) phases in six patients.
Two radiologists (7 years of experience in chest radiology) retrospectively evaluated the images and independently reviewed the tumour location (the lobe), size, shape (circular or lobulated), margins (well-defined or ill-defined), amount of calcification, calcification pattern, and attenuation (homogeneous or inhomogeneous and CT value) on precontrast and enhancement CT. To determine the amount of calcification within each mass, a subjective scoring system of 1–3 was used (<20%, 20-50%, and >50% calcification in the mass). A score of 1 was assigned to minimal calcification, and scores of 2 and 3 were assigned to moderate and severe calcification, respectively. The calcification pattern included strip-like punctate, sheet, ring, round, and irregular. The attenuation values of the tumours were measured in each mass/nodule in precontrast CT and all two enhancement phases of imaging in the exact same location in each mass/nodule to acquire the attenuation. Each lesion was measured three times and the average attenuation value was used for recording. The enhancement value=the attenuation value in enhancement CT-the attenuation value of precontrast CT. The size of each lesion was measured at its greatest single dimension. Other associated lesion satellites and enlarged lymph nodes at the mediastinum or hilus of the lung were also recorded.
The clinical and CT features displayed by the eight patients with pulmonary chondroma are shown in Table
Clinical and CT imaging findings in eight patients with an pulmonary chondroma.
Patient/age/gender | Location | Maximum diameter | Shape | Margin | Attenuation | Calcification Pattern and grade | Enhancement Attenuation | Enhancement attenuation | Enhancement pattern |
---|---|---|---|---|---|---|---|---|---|
1/57/F | right middle lob | 5.4 | mild lobulated | well-defined | 39HU | Ring/ 3 | |||
2/49/F | right lower lobe | 2.9 | mild lobulated | well-defined | 25HU | strip-like, punctate/ 1 | 31HU | 37HU | inhomogeneous enhancement |
3/45/M | left lower lobe | 4.2 | mild lobulated | well-defined | 27HU | strip-like, punctate/ 1 | 36HU | 41HU | inhomogeneous enhancement |
4/59/M | right upper lobe | 1.3 | mild lobulated | well-defined | 21HU | strip-like, punctate/ 1 | 27HU | 32HU | inhomogeneous enhancement |
5/73/M | left lower lobe | 1.1 | mild lobulated | well-defined | strip-like, punctate/ 1 | 29HU | 35HU | inhomogeneous enhancement | |
6/62/F | left upper lobe | 0.9 | mild lobulated | well-defined | 19HU | 29HU | 33HU | inhomogeneous enhancement | |
7/47/F | right upper lobe | 2.8 | mild lobulated | well-defined | 22 HU | strip-like, punctate/ 1 | 25HU | 30HU | inhomogeneous enhancement |
8/53/F | left lower lobe | 10.7 | mild lobulated | well-defined | 43HU | Ring/ 3 |
A 62-year-old woman with pulmonary chondroma. Mediastinal window images are shown. Computed tomography (CT) shows a slightly lobulated, well-defined nodule in the left upper lobe of the lung. (a) Precontrast axial CT scan shows an inhomogeneous soft tissue density nodule (19 HU). (b) Postcontrast axial arterial phase scan. (c) Postcontrast coronal arterial phase scan. (d) Postcontrast axial venous phase scan. The lesion shows a slight enhancement of 10 HU (arterial) and 14 HU (venous).
A 47-year-old woman with pulmonary chondroma. (a) Axial view and (b–d) lung window mediastinal window images. CT shows a mildly lobulated, well-defined nodule with strip-like, punctate calcification in the right upper lobe of the lung. (b) Precontrast scan shows an inhomogeneous soft tissue density nodule (22 HU). (c) Postcontrast arterial phase scan. (d) Postcontrast venous phase scan. The lesion shows a slight enhancement of 3 HU (arterial) and 8 HU (venous).
A 53-year-old woman with pulmonary chondroma. Axial view (a) and (b) mediastinal, bone-window images. CT shows a slightly lobulated, well-defined mass with a characteristic ring calcification in the left lower lobe of the lung. The patient with a large lesion (10.7 cm) showed chest wall adhesion suggestive of malignant infiltration. (c, d) The lesion was comprised of mature myxoid cartilage and calcification cartilage (Haematoxylin and Eosin; 400X magnification).
On plain CT images, seven of the cases (87.5%) showed a mass with varying degrees of calcification, which included five masses with strip-like punctate patterns defined as scoring 1 (Figure
Pathological examination showed that the tumours were composed of mature myxoid cartilage and calcification cartilage, with a fibrous pseudocapsule surrounding the tumour (Figures
The origin of pulmonary chondroma remains unclear [
Pulmonary chondroma was reported to commonly occur in adult women at 40–50 years of age [
The CT imaging appearance of pulmonary chondroma depends on the location and extent of involvement. According to our findings and previous reports, the typical CT features of pulmonary chondroma include (1) round or oval masses with clear boundaries, (2) lesion size ranging from 1.0 to 4.0 cm, with slight lobulation [
There are no reported CT findings specific for identification of pulmonary chondroma. In the present study, five of eight pulmonary chondromas were nodules (<3 cm diameter). A number of studies have suggested that CT findings of a smooth border, benign calcification (central, popcorn, laminated, or diffuse), and enhancement ≤15 HU may indicate benign nodules [
In the present study, there were three cases with pulmonary chondroma >3 cm with punctate (n=1, defined as scoring 1) or characteristic ring (n=2, defined as scoring 3) calcifications. These smooth border, mildly lobulated masses are difficult to diagnose. However, characteristic ring calcifications may be suggestive of pulmonary chondroma.
Chondroma can also display no or slight early enhancement and delayed enhancement after delivery of contrast agents, because of the relatively slow blood flow within the tumour [
Pulmonary chondroma is also one of the clinical manifestations of Carney’s triad, which involves the presence of at least two components of pulmonary chondroma, gastrointestinal stromal tumours, and extra-adrenal paraganglioma [
Because of its low morbidity, and as patients are often asymptomatic, pulmonary chondroma can be easily misdiagnosed as tuberculosis tumours, hamartoma (particularly cartilage hamartoma), and peripheral lung cancer. Indeed, patients with a previous history of tuberculosis were commonly diagnosed with suspected pulmonary tuberculoma [
In conclusion, the preoperative diagnosis of pulmonary chondroma is difficult, and a variety of imaging techniques are required for comprehensive diagnosis. Using CT, we found that lesions showing a solitary, mildly lobulated mass with a well-defined margin, calcification (punctate, strip-like, or ring calcifications), and slight enhancement (<15 HU) should be considered potential pulmonary chondroma. Nevertheless, differential diagnosis of hamartoma (particularly cartilage hamartoma), tuberculosis tumour, and peripheral lung cancer is also important. Further clinical, imaging, and pathological studies are required to improve the diagnosis of this disease. After diagnosis of pulmonary chondroma, further examination is also required to exclude Carney’s triad.
The data used to support the findings of this study are available from the corresponding author upon request.
The authors declare that they have no conflicts of interest.