Case of the Month, January 2017, Page 3

Answer: Whole body PET/CT. The patient has a lung mass consistent with malignancy. Whole body PET/CT should be ordered for staging.

Whole body PET/CT

Figures 4-8

For larger images, please click on Bhangoo4 , Bhangoo5 , Bhangoo6 , Bhangoo7  and Bhangoo8

   

i) Moderately active left upper lobe pulmonary lesion, likely representing lung malignancy, either primary or metastatic.

ii) Intense metabolically active pretracheal and subaortic lymph nodes concerning for nodal metastases.

iii) Two large intense hypermetabolic hepatic lesions, consistent with metastases. 

Conclusion

The patient’s hoarse voice is due to left vocal cord paralysis secondary to left recurrent laryngeal nerve compression by sub-aortic nodal metastases from underlying likely lung adenocarcinoma. The patient underwent mediastinoscopy with lymph node biopsies which did not show any evidence of metastatic carcinoma. Unfortunately, no further information is available as the patient was lost to follow-up.

Discussion

Patients who present with a hoarse voice for more than two weeks, in the absence of signs or symptoms of acute respiratory illness, should be referred to an ENT physician for evaluation by laryngoscopy1. There are then two goals of imaging: i) to characterize and stage a laryngeal or pharyngeal tumor, or ii) identify a cause for vocal cord paralysis2.

Vocal cord paralysis is a common etiology of a hoarse voice. Patients with vocal cord paralysis may also present with aspiration, globus sensation, or shortness of breath. The most sensitive imaging findings for vocal cord paralysis on CT include: ipsilateral piriform dilation, ipsilateral laryngeal ventricle dilation and medial rotation and thickening of the aryegpiglottic fold. The differential diagnosis for the above findings should include laryngeal malignancy, arytenoid cartilage dislocation due to trauma and asymmetric visualization of the vocal cords due to oblique positioning of the patient (or use of oblique imaging planes)3.

Vocal cord paralysis is caused by dysfunction of the ipsilateral vagus nerve or its branch vessel, the recurrent laryngeal nerve. Once vocal cord paralysis is suspected, CT of the neck and chest—as well as an MRI of the brain—should be obtained to examine the course of the vagus nerve from the medulla to the ipsilateral recurrent laryngeal nerve2. For identifying etiologies of vocal cord paralysis, it is important to remember that the right recurrent laryngeal nerve courses below the brachiocephalic artery after branching from the vagus nerve. On the other hand, the left recurrent laryngeal nerve courses underneath the aortic arch through the aortopulmonary window after exiting the vagus nerve.

The most common etiologies of vocal cord paralysis include idiopathic, traumatic/iatrogenic, and neoplastic causes. In patients without an identified cause on imaging, vocal cord paralysis is thought to be related to inflammation secondary to infection or toxicity (for example, vincristine). Malignancy and associated lymphadenopathy anywhere along the course of the vagus and recurrent laryngeal nerves can also cause vocal cord paralysis. As in this case, mediastinal lymphadenopathy in the aortopulmonary window related to a primary lung carcinoma resulted in compression of the left recurrent laryngeal nerve and as a result, left vocal cord paralysis. With the appropriate clinical history, traumatic or iatrogenic injury to the neck/mediastinum (intubation, thyroidectomy, carotid endarterectomy…) should also be considered as an etiology of vocal cord paralysis. Other less common causes can include vascular pathology such as aortic aneurysms, left atrial enlargement or pulmonary artery enlargement3. Treatment of vocal cord paralysis is directed towards the underlying cause.

Works Cited

1. Bruch et. al. Hoarseness in adults. UpToDate. Aug 8, 2016.https://www.uptodate.com/contents/hoarseness-in-adults?source=search_result&search=vocal%20cord%20paralysis&selectedTitle=1~73#H7

2. Pretorius et. al. Investigating the hoarse voice. BMJ. 2008 Oct 8; 337;a1726

3.  Paquette et. al. Unilateral vocal cord paralysis: a review of CT findings, mediastinal causes and the course of the recurrent laryngeal nerves. Radiographics. 2012 May-Jun;32(3):721-40

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