Endobronchial ultrasound-guided transbronchial needle aspiration of lesions in mediastinum
Department of Cardiothoracic Surgery, Odense University Hospital, Odense, Denmark
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Original Article
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Abstract
Background: Lesions in mediastinum can represent malignancy and warrants further workup. Commonly a diagnosis is achieved by conventional bronchoscopy, transbronchial needle aspiration or CT guided fine needle aspiration, however a number of patients remain undiagnosed despite these common investigations.
Methods: During a period of 36 months 601 patients underwent EBUS at our institution. Two hundred ninety three patients had an established diagnosis of lung cancer and were referred to us for mediastinal staging. The remaining patients had a radiologically suspicious intrathoracic lesion of which 107 had an undiagnosed lesion in mediastinum. All patients had been investigated by previous chest CT and bronchoscopy including brush cytology but remained undiagnosed.
Results: Of the 107 patients with undiagnosed lesions in the mediastinum 89 enlarged lymph nodes and 18 mediastinal tumours. Forty-eight of the 89 patients (54%) with enlarged mediastinal lymph nodes were diagnosed by EBUS of the remaining 41 patients 11 went on to more invasive methods. In patients with undiagnosed tumours in mediastinum we achieved a final diagnosis by EBUS in 14 of the 18 patients (78%) and 3 went on to more invasive methods.
Conclusion: EBUS provides a final diagnosis in 78% of patients with tumour in mediastinum and in more than half of patients with enlarged lymph nodes despite previous workup.
Key words
lung cancer; tumour mediastinum; EBUS
J Thorac Dis 2010;2:125-128. DOI: 10.3978/j.issn.2072-1439.2010.02.03.2
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Introduction
Lesions in mediastinum represent enlarged lymph nodes or
tumour, and warrants further workup. Commonly a diagnosis is
achieved by conventional bronchoscopy, transbronchial needle
aspiration (TBNA) or CT guided fine needle aspiration (CTFNA),
however a number of patients remain undiagnosed
despite these common investigations. A tissue diagnosis is often
achieved by repeating the TBNA/ CT-FNA or performing a
mediastinoscopy which is an invasive surgical procedure that
poses a small but significant risk to the patient (1).
Endobronchial ultrasound-guided trans-bronchial needle
aspiration (EBUS) is a well established method for mediastinal staging of lung cancer (2-6). Previous investigations have
demonstrated that EBUS may also be used in the diagnostic
workup of patients with suspicious central masses (7,8). We
recently demonstrated that the yield of EBUS for undiagnosed
intra-thoracic lesions in general was 45%-55% (9,10). The
yield of EBUS depends on previous diagnostic workup and the
anatomical location of the intra-thoracic lesion (10).
Patients with undiagnosed lesion in mediastinum despite
previous workup are a common challenge for the clinician. We
conducted an analysis of our data to investigate if EBUS can
provide a diagnosis of undiagnosed lesions in mediastinum
despite previous workup.
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Material and methods
During a period of 36 months ( January 2006 to December
2008) 601 patients underwent EBUS at our institution. Two
hundred ninety three patients had an established diagnosis of
lung cancer and were referred to us for mediastinal staging. The
remaining 308 patients had a radiologically suspicious lesion but
no diagnosis in mediastinum (n = 107) consisting of enlarged
lymph nodes in the mediastinum (n = 89) and suspicious tumor
in the mediastinum (n = 18), peripheral lung parenchyma (n = 95), a central lesion in lung parenchyma (n = 82), bilaterally lung
lesions (n = 18) or rare causes (n = 6). All 308 patients had been
investigated by previous chest CT and bronchoscopy including
brush cytology but remained undiagnosed.
All patient charts were reviewed and the following data
collected for analysis: age, sex, indication for diagnostic
work-up, surgical notes , surgical procedures, complications,
cytology report, histology reports after further investigations
and outpatient notes. All EBUS examinations were performed
in general anesthesia with a linear scanner (BF-UC160F,
Olympus). Masses in the mediastinum, lung parenchyma or
enlarged paratracheal or hilar lymph node stations 2, 3, 4, 7, 10
and 11 according to Mountain et al. (11) were systematically
identified and punctured. Fine needle aspiration was performed
with a 22G needle (NA-201SX-4022, Olympus) during realtime
EBUS. Two aspirations were performed from each
lesion to ensure that the biopsy contained sufficient material.
Aspirated material was expelled onto glass slides and smeared for
cytological examination or expelled into saline for preparation of
cell blocks for histological examination. Rapid on-site evaluation
was not performed. Instead, all biopsies were reviewed the
following day by an experienced pathologist, and classified as “malignant”, “benign” or “non-diagnostic”. The latter group
was further subdivided into biopsies with adequate cell sample
(presence of lymphocytes) or inadequate cell sample without
lymphatic tissue. Diagnostic yield was defined as samples which
provided a final malignant or benign diagnosis.
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Results
The median age of the 308 patients with an undiagnosed
radiologically suspicious lesion in the chest was 67 years (range
29 to 86 years) and 172 were men (56%). There was no operative
mortality or any surgical complications. All patients were
discharged from the hospital on the day of surgery. Diagnostic
yield for all patients was 55%.
Forty-eight of the 89 patients (54%) with enlarged
mediastinal lymph nodes were diagnosed by EBUS of the
remaining 41 patients 11 went on to more invasive methods of
which 3 patients were diagnosed with malignancy, 6 had a benign
diagnosis and two had normal tissue (Fig 1).
In the group with undiagnosed tumours in mediastinum
we achieved a final diagnosis by EBUS in 14 of the 18 patients
(78%). In the remaining 4 patients, 1 patient was later diagnosed with malignancy, 1 with benign disease, 1 with normal findings
and 1 was followed in outpatient clinic (Fig 2).
Inadequate tissue samples were obtained in 6 patients (7%)
with enlarged lymph nodes and in 1 patient (5%) with tumour in
mediastinum.
EBUS did not provide an immediate malignant or benign
diagnosis in 45 patients, where 7 patients (7%) had inadequate
tissue samples and 38 patients (35%) had adequate tissue
samples. Four-teen patients were referred for more invasive
methods including mediastinoscopy (n = 8), thoracoscopy (n
= 4) and thoracotomy (n = 2). Five patients with inadequate
diagnostic material and twenty-six patients with adequate cell
samples were followed in the outpatient clinic because a new
chest-CT demonstrated regression of the lesion in mediastinum.
Fig 1 demonstrate diagnosis for patients with enlarged lymph nodes
Fig 2 demonstrate diagnosis for patients with tumour in mediastinum
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Discussion
Patients with radiologically suspicious lesion in mediastinum
who remain undiagnosed despite conventional workup
are a common challenge in the clinics. We have previously
demonstrated that EBUS is a valuable diagnostic tool in
approximately 55% of patients with undiagnosed intra-thoracic
lesions (10).
One third of the patients with enlarged mediastinal lymph nodes were found with malignancy (n=26) and yield was 54%
which was also found in other studies (12,13). Yield is lower
than most physicians would expect since it is generally believed
that EBUS is primarily used to stage mediastinal lymph nodes in
lung cancer patients. However, it is important to distinguish the
two patient populations: those with an established lung cancer
diagnosis and those who are referred solely with enlarged lymph
nodes which may simply be secondary to previous inflammation.
Despite previous diagnostic work up sarcoidosis is still the most
likely benign diagnosis in patients with enlarged lymph nodes
(14,15), which were also found in one third of the patients in our
study (n = 27).
In patients with tumour in mediastinum yield was 78%. Two
thirds of these patients were found with malignancy (n = 11)
and 4 patients were diagnosed with thyroid disease, which has
been demonstrated previously (13).
Lymphoma was diagnosed in 5 patients with EBUS and 1
patient after mediastinoscopy which confirm that lymphomas
can be diagnosed with EBUS but surgical biopsies are required
to diagnose specific lymphoma subtypes not readily amenable to
diagnosis with low volume specimens (14).
As demonstrated in a previous study (10) yield is different
in the two groups as the frequency of malignancy is higher for
patients with mediastinal tumor than enlarged lymph nodes which can be explained by adenopathy secondary to previous
inflammation or infection.
In the present study our patients are highly selected and thus
biased because they were only referred to us if conventional
methods failed to give a diagnosis. Diagnostic yield would
increase if all patients with undiagnosed lesions in mediastinum
were referred directly to EBUS.
We have not encountered any complications in 601
consecutive cases. As demonstrated in many other studies EBUS
is a safe, minimally invasive and cost-effective tool because it
allows investigation in an outpatient setting (16).
In patients who remain undiagnosed after conventional
workup EBUS represents a fine alternative to more invasive
diagnostic procedures and could be the first choice. However,
even though EBUS provides a diagnosis in the majority of the
patients, some will remain undiagnosed and need further more
invasive procedures.
In conclusion this minimally invasive diagnostic modality
provides a final diagnosis in 78% of patients with tumour in
mediastinum and in more than half of patients with enlarged
lymph nodes without exposing the patient to the risk of
complications with more invasive procedures.
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References
Cite this article as: Eckardt J. Endobronchial ultrasound-guided transbronchial needle aspiration of lesions in mediastinum. J Thorac Dis 2010;2(3):125-128. doi: 10.3978/j.issn.2072-1439.2010.02.03.2
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