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Introduction
EUS has been found to be an excellent way to access and biopsy structures in the thorax, particularly the mediastinum. However, we are unaware of any reports in which EUS has been used to aspirate bony structures in the thorax or elsewhere. We present a case in which a thoracic vertebral metastasis was aspirated by EUS to help address a clinical dilemma.
Photos were made using Adobe Photoshop 8.0, and Videos editied using Adobe Premiere 1.5. EUS was performed with Pentax solid state equipment and captured to SVHS tape.
Case
A 79 year old female was found to have a right lower
lobe nodule on a chest x-ray. This eventually led to a CT scan which showed right lower lung nodule that was felt to be malignant (Figure 1) as well as mediastinal adenopathy and also probable metastatic disease involving the lower thoracic vertebral bodies and an epidural soft tissue mass around T11. (Figure 2) A PET scan confirmed the findings (Figures 3-5), and showed no other concerning features.
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Figure 3 |
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Figure 5 |
Her past medical history revealed that she had an abdominal aortic aneurysm repaired 4 years earlier and she had an ischemic cardiomyopathy with an ejection fraction of 35-40%. She also had a history of localized breast cancer treated with lumpectomy and radiation therapy 11 years earlier.
She had a 40 pack year history but stopped smoking 20 years earlier.
Her physical exam revealed evidence of her previous breast cancer surgery but was otherwise unremarkable for age. No weakness in her legs or numbness was noted.
The working diagnosis was primary lung cancer, although breast cancer was also a consideration. EUS was requested.
At the time of EUS, a subcarinal lymph node was aspirated (Video 1), with preliminary cytology revealing non-small cell carcinoma (Figure 6). To complete staging of possible M1 lung cancer or to diagnose a possible breast malignancy, the thoracic vetebrum was visualized and biopsied (Video 2) revealing non-small cell cancer, with similar features to the mediastinal lymph node (Figure 7). The lesion did not stain for TTF-1 (Figure 8), but was strongly positive for estrogen receptor (Figure 9), establishing a diagnosis of metastatic breast cancer.
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MRI was obtained to look for possible spinal cord impingement, which was unremarkable (Figure 10). The patient was treated with the aromatase inhibitor letrozole1, with slow improvement in her thoracic disease.
Discussion
EUS is a technique that is growing in popularity. A recent PubMed search showed over 2000 articles which refer to this technique. Recent reviews highlight the use of EUS in defining mediastinal masses.2,3 However, our case presents an additional dilemma beyond staging the mediastinum. Preoperative imaging suggested a bony metastasis. If this were all lung cancer, it would be an inoperable presentation, with treatment directed towards a pulmonary primary. If breast cancer were present, hormone manipulation would be a less toxic alternative.4 EUS allowed a one-step diagnostic and staging procedure, which resulted in a less aggressive, but apparently successful approach to therapy. We present this case since we were unable to find other instances of EUS being utilized to access bony disease, and that it appeared to appropriately direct therapy.
In addition to the posterior mediastinum, the esophagus is in direct contact or close proximity with the vertebrae. (Figure 11) Although this particular application of EUS seems unusual, it makes anatomic sense. Although we have no data to support or refute the infection risk, we feel meticulous care should be taken to avoid infection of bone. In our case we aspirated apparent tumor that appeared to project off the bone and had prepped the area and biopsy channel with absolute ethanol. Alcohol or iodine based solutions in the biopsy channel as well as antibiotics can be considered.
References
1. Amar S, Roy V, Perez EA. Letrozole: present and future role in the treatment of breast cancer. Expert Opin Pharmacother. 2007 Aug;8(12):1965-75.
2. De Luca L, Di Bella S, D'Amore E. Mediastinal and gastric EUS: indications and technique of examination. Minerva Med. 2007 Aug;98(4):423-9.
3. Walsh PR, Williams DB. Mediastinal adenopathy: finding the answer with endoscopic ultrasound-guided fine-needle aspiration biopsy. Intern Med J. 2005 Jul;35(7):392-8
4. Kennedy MJ. Metastatic breast cancer. Curr Opin Oncol. 1996 Nov;8(6):485-90.
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