common sites of breast cancer metastases include regional lymph nodes , bones , liver , lungs and brain .
metastatic breast and lung cancers are the most common non - traumatic causes of brachial plexopathy , after radiation induced fibrosis . because one of the major lymphatic drainage of the breast is through the apex of the axilla , it is not uncommon for metastatic breast cancer to invade the brachial plexus .
a 56-year - old woman diagnosed with infiltrating ductal carcinoma of the left breast had undergone left modified radical mastectomy followed by radiotherapy and adjuvant chemotherapy .
she presented to her oncologist with left para sternal chest wall recurrence with restriction of movement of the left upper limb .
the patient was referred for 18f - fdg pet / ct to evaluate the extent of recurrent / metastatic disease .
whole - body contrast enhanced pet / ct was acquired 1 hour following the intravenous injection of 296 mbq of 18f - fdg on pet ct discovery 600 , with 16 slice ct scanner .
the scan showed ill - defined heterogeneously enhancing hypermetabolic soft tissue along left brachial plexus [ figure 1 ] with intra - spinal extension through neural foramina at c5-c6 and c6-c7 levels on the left side [ figure 2 ] along with few ill -defined intra - spinal enhancing lesions at d4-d5 , d7-d8 and d8-d9 levels [ figure 3 ] and heterogeneously enhancing extra - axial lesion in left c - p angle region [ figure 4 ] .
the scan also showed heterogeneously enhancing ill - defined soft tissue lesion in subcutaneous plane in left para - sternal region in anterior chest wall at 1st intercostal space [ figure 5 ] along with soft tissue in antero - superior mediastinum extending along left proximal common carotid artery [ figure 6 ] .
maximum intensity projection ( mip ) and coronal 18f - fdg pet - ct images show linear extension of tracer activity from superomedial aspect ( supra / infraclavicular ) to lateral aspect of the left axilla .
ill - defined heterogeneously enhancing hypermetabolic soft tissue along left brachial plexus with intra - spinal extension through neural foramina at c5-c6 and c6-c7 levels on left side .
fdg avid heterogeneously enhancing extra - axial lesion in left c - p angle region .
fdg avid heterogeneously enhancing ill - defined soft tissue lesion in subcutaneous plane in left para - sternal region in anterior chest wall at 1st intercostal space .
fdg avid soft tissue in antero - superior mediastinum extending along left proximal common carotid artery .
the two major causes of brachial plexopathy in breast cancer patients are metastatic invasion of and radiation damage to the plexus .
it is difficult to image because of complicated anatomy of the plexus and its immediate anatomical relationship to blood and lymphatic vessels .
computerized tomography scanning has been used to assess the brachial plexus but it has several limitations .
the neurovascular bundle of the axillary artery and brachial plexus may appear as a single structure when the administration of contrast medium is poorly timed . in a series of 46 patients with proven metastatic plexopathy
a ahmad et al also had either normal ct or the appearance of minimal thickening of the brachial plexus in 6 cases out of the total 11 cases in their study .
its superiority to ct scanning relates to its ability to differentiate more accurately nerves from surrounding vessels and soft tissues .
review of the literature suggests that there is no doubt that mri can delineate both the normal and abnormal anatomy of the brachial plexus in more detail than ct scan .
some studies have shown that tumor recurrence has a higher signal intensity than radiation fibrosis on t2-weighted images , although other authors have reported increased t2 signal in both metastatic and radiation plexopathy patients .
fdg - pet is a useful imaging technique to study the brachial plexus in breast cancer patients and that it may be useful to monitor treatment efficacy as well .
the current data is insufficient to suggest unequivocally that fdg - pet may be useful in distinguishing neoplastic from radiation plexopathy .
maximum intensity projection ( mip ) and coronal 18f - fdg pet / ct images show linear extension of tracer activity from superomedial aspect ( supra / infraclavicular ) to lateral aspect of the axilla closely related to the subclavian / axillary vessels .
dual time point imaging may have some role in this scenario and further work in this area may be proved useful .
 we report a case of a 56-year - old woman diagnosed with infiltrating ductal carcinoma of the left breast , who had undergone left modified radical mastectomy followed by radiotherapy and adjuvant chemotherapy . 
 fdg pet - ct showed metastatic brachial plexopathy with intra - spinal and extra - axial brain metastasis . 
 metastatic brachial plexopathy along with brain and spinal metastasis is a rare condition with very less incidence . 
 the scan also showed left para - sternal anterior chest wall recurrence with antero - superior mediastinal metastasis . 
 18fdg - pet scanning is a useful tool in evaluation of patients with suspected metastatic plexopathy 
 . it may also be useful in distinguishing between radiation - induced and metastatic plexopathy . 
 typical pattern of fdg uptake and dual time point imaging may increase specificity and require further evaluation . 
Introduction
Case Report
Discussion
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