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A 58-year-old
CHEST Postgraduate Education Corner
A Lung Mass Causing Cardiovascular
Impairment
Daniel Menzies, MB, ChB, MD; John Gosney, MB, ChB, MD;
Mark Elias, MB, BCh; Stephen Kelly, BM, BCh; and Mark Steel, MBBS, PhD
(CHEST 2009; 136:1682–1685)
woman presented to our hospital
with progressive breathlessness and cough.
Her cough, which had not responded to empiric
antibiotic therapy initiated by her family physician,
had initially developed 6 weeks previously. Two
weeks prior to hospital admission, she noted worsening
of the cough and the development of breathlessness,
with the result that her usually unlimited
exercise tolerance was reduced to approximately
20 yards. Her previous medical, occupational, and
travel histories were unremarkable, and she had
been receiving no regular medication. She was
currently a smoker with a total of 20 pack-years.
On examination, the patient was centrally cyanosed
with resting oxygen saturations of 78% while
breathing room air. Her jugular venous pressure
was elevated, and there was moderate peripheral
ankle edema that was compatible with right heart
failure. An examination of her chest revealed a
dull percussion note and reduced breath sounds
throughout the right hemithorax. Arterial blood
gas analysis performed with the patient breathing
1 L of oxygen via nasal cannula demonstrated the
following results, consistent with acute-on-chronic
type II respiratory failure: pH, 7.27; Po2, 101.5
mm Hg; Pco2, 82.0 mm Hg, and bicarbonate
concentration, 36 mmol/L. Renal and liver func-
Manuscript received January 2, 2009; revision accepted April 14,
2009.
Affiliations: From the Department of Respiratory Medicine
(Drs. Menzies, Kelly, and Steel) and the Department of Radiology
(Dr. Elias), Wrexham Maelor Hospital, Wrexham, UK; and
the Department of Pathology (Dr. Gosney), Royal Liverpool
University Hospital, Liverpool, UK.
Correspondence to: Daniel Menzies, MD, Department of
Respiratory Medicine, Wrexham Maelor Hospital, Wrexham,
Wales, LL137TD, UK; e-mail: danielmenzies@mac.com
© 2009 American College of Chest Physicians. Reproduction
of this article is prohibited without written permission from the
American College of Chest Physicians (www.chestjournal.org/site/
misc/reprints.xhtml).
DOI: 10.1378/chest.09-0008
CHEST IMAGING AND PATHOLOGY FOR CLINICIANS
tion test results were normal, as were hematologic
parameters, including a CBC with cell differential.
The chest radiograph obtained at hospital admission
(Fig 1) identified a large, confluent, welldemarcated
mass filling the majority of the right
hemithorax, with encroachment toward the mediastinum
and associated displacement of the central
structures including the heart. Subsequent
contrast-enhanced CT scans of the thorax (Fig 2A
and B) and abdomen also demonstrated the presence
of a large mass that measured approximately
18 16 cm in the axial plane, impinging on and
compressing both the inferior vena cava and right
atrium. No significant thoracic or extrathoracic
adenopathy was identified. The mass appeared to
Figure 1. Posteroanterior chest radiograph demonstrating a
large mass occupying the majority of the right hemithorax with
associated displacement of the heart and mediastinum. The
medial border of the mass is visible behind the cardiac
silhouette (arrows) making diaphragmatic displacement or
herniation a less likely explanation. The upper mediastinum is
normal in dimension.
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Figure 2. CT scan images of the thorax clearly show significant
compression of the inferior vena cava and right side of the
heart by a large tumor the image of which was not enhanced
with contrast medium compared with the precontrast localizer.
The mass is notably heterogeneous in appearance, with
areas of low-attenuation signal (dashed arrows), admixed with
high-density islands of presumed calcification (solid arrows).
Although not shown, the liver was displaced inferiorly, and
there was a small associated pleural effusion.
arise within the lung parenchyma and was noted to
be heterogeneous with variable radiographic attenuation
containing areas of interspersed calcification.
The remainder of the lung parenchyma was
unremarkable. Because the patient was acutely unwell
with respiratory compromise, emergency surgical
resection was performed, and a 3.8-kg (8.4lb)
tumor was excised from the right hemithorax,
along with the lower lobe of the right lung. Figures
Figure 3. The excised mass, 18 cm in maximal diameter,
consisting of large, glassy lobules separated by thin fibrous
bands.
3 and 4 show the macroscopic and microscopic
features, respectively. The patient made an uneventful
recovery; at routine follow-up 6 weeks
following surgery, there were no clinical features
of right heart failure, and her resting oxygen
saturations were 98% while breathing room air.
Figure 4. Medium-power photomicrograph showing the characteristic
bronchiolar-like structures and adipose tissue at the
margin of one of the lobules of mature cartilage that made up the
bulk of the lesion (hematoxylin-eosin, original 100).
What is the diagnosis?
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Diagnosis: Chondroid hamartoma
Clinical and Radiologic Features
Chondroid hamartomas are relatively common
lung neoplasms and are often detected incidentally
on chest imaging or at postmortem examination.
They account for approximately 3% to 8% of all lung
tumors, and 10% of all ultimately benign lesions
removed for suspected lung cancer. 1,2 Sporadic cases
of multiple chondroid hamartoma formation mimicking
lung metastasis have also been reported. 3,4
The majority of these tumors are peripherally situated
in the lung parenchyma and relatively small,
ranging from 1 to 4 cm in diameter. Approximately
10% develop in one of the more central airways,
which can occasionally result in obstructive symptoms.
5,6 Rarely do chondroid hamartomas grow to
the size seen in our patient, and there are limited
published case reports 7–9 of these tumors presenting
with compressive mass-effect symptoms. In these
circumstances, possible mechanisms for acute decompensation
include narrowing of major airways,
pulmonary embolus, and superior vena cava occlusion.
In our patient, the likely mechanism was the
critical impairment of venous return to the right side
of the heart, with a secondary reduction in cardiac
output.
When detected as asymptomatic solitary pulmonary
nodules, it is possible for chondroid hamartomas to be
mistaken radiologically and clinically for bronchial carcinomas.
Chondroid hamartomas comprise variable
amounts of fat, connective tissue, cartilage, and
bone. As such, their appearance on a CT scan is of a
heterogeneous mass, often containing both areas of
calcification and also of low attenuation consistent
with the presence of fat. Some authors 10 have reported
that this radiologic feature in a lung lesion
with smooth and defined margins can usefully differentiate
hamartomas from carcinomas. Partial volume
effect (whereby a number of structures of
variable attenuation are measured together and their
density averaged) can lead to erroneous Hounsfield
unit readings and can occasionally misrepresent anatomically
small foci of fat seen on a CT scan.
Thin-slice multiplanar reconstruction of images obtained
from our patient revealed low-density foci
free from such potential artifact with Hounsfield unit
readings of 30 (which is regarded as representative
of fat). Alternative causes of lipid-containing
opacities in the chest include liposarcomas, metastatic
renal carcinoma, resolving hematoma, and fat
embolism. 11 The relative position of such a mass
within the thorax (along with the clinical context) can
further define the probability of each diagnosis
because hematomas and liposarcomas are usually
localized to the chest wall. If chondroid hamartomas
are small and centrally located (particularly if they
are found to be partially impinging on the bronchial
lumen), it can be difficult to differentiate them
radiologically from carcinoid tumors, which frequently
occupy a similar anatomic position. Although
carcinoid tumors also contain variable amounts of
calcification, unlike chondroid hamartomas, they ordinarily
demonstrate a high degree of homogeneous
contrast enhancement.
Other tumors, including lung cancer, pulmonary
sarcoma, and mesothelioma, can present as large
masses occupying most of the hemithorax, although
these are usually accompanied by local or systemic
features of malignancy such as pain, weight loss,
anorexia, or paraneoplastic phenomena. Other radiologic
features usually accompany malignant largevolume
thoracic tumors, including significant adenopathy
or a moderate-to-large pleural effusion,
neither of which were seen in our patient. Benign
and malignant solitary fibrous tumors of the pleura
can also be very large at the time of presentation.
Unlike the CT scan appearances of our patient in
Figure 2, these rare tumors usually have an acute
angle with the associated pleural surface from which
they arise, demonstrate contrast enhancement because
of considerable vascularity, and only rarely
have calcified foci. 10 The presence of radiographic
calcification in chondroid hamartomas is related to
the size of the tumor, and is observed in 75% of
those that enlarge to 5 cm in diameter. 10,12 The
CT scan of our patient showed a well-circumscribed,
smooth-edged (although very large), non–contrastenhancing
tumor featuring hypodense areas consistent
with fat, and also areas of calcification associated
with cartilage and bone formation, although difficulty
remained in positively identifying the relationship
between the mass and the pleural surface. In
this situation, a combination of the clinical context
and the radiologic findings made chondroid hamartoma
the most likely diagnosis. When uncertainty
remains about the origin of large thoracic masses,
MRI can be helpful in differentiating intraparenchymal
from pleural tumors. The rapidly declining
cardiovascular status in the patient described precluded
this type of potentially diagnostic imaging
prior to definitive surgical intervention.
Pathologic Features
The excised specimen was a dense, lobulate, ovoid
mass, 20 cm in maximal diameter and weighing 3.8
kg (8.4 lb). Slicing revealed lobules of glassy material
separated by fibrous septa (Fig 3). The lesion had the
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typical features of a benign chondroid hamartoma,
comprising masses of cartilage with focal calcification
separated by fibrous bands in which cleft-like
structure lines were lined with flattened respiratory
epithelium (Fig 4).
The entity known for many years as chondroid
hamartoma is now generally considered to be a
slow-growing, benign, mesenchymal neoplasm in
which the epithelial components are normal small
airways entrapped within a purely mesenchymal
tumor. 12,13 Mesenchymoma was at one point suggested
as an appropriate name for these lesions, but
chondroid hamartoma is deeply embedded in clinical
and pathologic practice and remains the internationally
recognized term for such tumors. Our case is
typical in its gross and microscopic features (Figs 3,
4, respectively), being remarkable only for its enormous
size. There has been a single isolated report 14
of probable malignant transformation of a pulmonary
chondroid hamartoma, but it is difficult to exclude
the possibility that this lesion was fundamentally
different, and the behavior of chondroid hamartomas
is almost universally indolent.
Conclusion
Chondroid hamartomas can enlarge to become
massive tumors, occasionally presenting with associated
mass-effect clinical symptoms and signs. More
frequently, these tumors are detected as solitary
pulmonary nodules that require differentiation from
other potentially more serious causes of intrapulmonary
lesions, in particular bronchial carcinoma. On
admission to the hospital, our patient was in respiratory
failure, and there was insufficient time to
undertake a biopsy and formalize this distinction. A
pragmatic decision was made to undertake surgery
based on the clinical and radiologic probability that
the tumor was benign but causing life-threatening
cardiovascular compromise. Clinicians should be
aware of the possibility that chondroid hamartomas
can become extremely large, but that even in these
circumstances surgical removal is likely to prove
curative.
Acknowledgments
Financial/nonfinancial disclosures: The authors have reported
to the ACCP that no significant conflicts of interest exist
with any companies/organizations whose products or services
may be discussed in this article.
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