FDG-PET/CT Skull Base to Mid-Thigh Less than 1% of breast cancers initially present as axillary adenopathy [32,33]. Historically, mammography, US, and breast MRI have helped to identify the primary malignancy in patients with pathologic axillary adenopathy from unknown primary. However, mammography and US have relatively low sensitivity for detecting the primary breast lesion [31,159]. The addition of breast MRI has improved sensitivity [160] because MRI is able to detect the primary breast lesion in 36% to 86% of cases [39]. Although PET/CT can be helpful in identifying the site of an unknown primary, for breast cancer, there are little data to support its routine use. MRI Breast Once the suspicious axillary node has been documented as metastatic nodal disease, then breast MRI can detect a mammographic or sonographic occult breast lesion with high sensitivity for detecting an in-breast lesion or confirm no breast primary [34,35]. In a meta-analysis of 8 retrospective studies involving 220 patients, MRI detects an occult breast cancer in 72% of cases with a pooled sensitivity of 90% and a specificity of 31% [39]. MRI can also help further characterize the axillary mass by evaluating its relationship to adjacent vessels, the chest wall, and other axillary structures. In a meta-analysis of 26 studies looking at the diagnostic performance of MRI in detecting Imaging of the Axilla metastatic nodal disease, the pooled sensitivity and specificity in patients with breast cancer is 77% and 90%, respectively [123]. Sestamibi MBI There is no relevant literature supporting the use of Tc-99m sestamibi MBI for imaging the axilla in patients with suspicious axillary nodes detected on mammography and US. US-Guided Core Biopsy Axillary Node US-guided biopsy (either core needle biopsy or FNA) may provide a diagnosis for morphologically abnormal lymph nodes detected on imaging.
Imaging of the Axilla. FDG-PET/CT Skull Base to Mid-Thigh Less than 1% of breast cancers initially present as axillary adenopathy [32,33]. Historically, mammography, US, and breast MRI have helped to identify the primary malignancy in patients with pathologic axillary adenopathy from unknown primary. However, mammography and US have relatively low sensitivity for detecting the primary breast lesion [31,159]. The addition of breast MRI has improved sensitivity [160] because MRI is able to detect the primary breast lesion in 36% to 86% of cases [39]. Although PET/CT can be helpful in identifying the site of an unknown primary, for breast cancer, there are little data to support its routine use. MRI Breast Once the suspicious axillary node has been documented as metastatic nodal disease, then breast MRI can detect a mammographic or sonographic occult breast lesion with high sensitivity for detecting an in-breast lesion or confirm no breast primary [34,35]. In a meta-analysis of 8 retrospective studies involving 220 patients, MRI detects an occult breast cancer in 72% of cases with a pooled sensitivity of 90% and a specificity of 31% [39]. MRI can also help further characterize the axillary mass by evaluating its relationship to adjacent vessels, the chest wall, and other axillary structures. In a meta-analysis of 26 studies looking at the diagnostic performance of MRI in detecting Imaging of the Axilla metastatic nodal disease, the pooled sensitivity and specificity in patients with breast cancer is 77% and 90%, respectively [123]. Sestamibi MBI There is no relevant literature supporting the use of Tc-99m sestamibi MBI for imaging the axilla in patients with suspicious axillary nodes detected on mammography and US. US-Guided Core Biopsy Axillary Node US-guided biopsy (either core needle biopsy or FNA) may provide a diagnosis for morphologically abnormal lymph nodes detected on imaging.