Metastatic Adenocarcinoma in the Brain: Magnetic Resonance Imaging with Pathological Correlations to Mucin Content

Background: Hypointense signal appearance of metastatic adenocarcinoma on T2-weighted imaging (T2-WI) has been infrequently documented. The purpose of this report was to evaluate the degree to which mucin content affects signal manifestations on conventional MR imaging. Patients and Methods: This series of 24 cases with intracerebral metastatic adenocarcinoma was assessed retrospectively, focusing on the association between hypointense appearance on T2-WI and intratumoral mucin content. Results: Among the 24 metastatic adenocarcinomas, intratumoral mucin was histopathologically confirmed in 8 lesions. Of these, 4 masses were demonstrated as hyperintense signal on T2-WI. The other 4 masses were depicted as isointensity. No cases were identified with hypointense signals in mucin-containing metastatic adenocarcinoma. Conversely, only 2 metastatic tumors originating from the stomach exhibited hypointense signal lesions on T2-WI. No histological or magnetic resonance imaging evidence of blood products or other forms of iron were identified as causes of the hypointense appearance on T2-WI. Conclusion: This hypointense signal may simply reflect the relatively shorter T2 relaxation time of the primary tissue from which metastases arose. Intratumoral mucin itself may be considered to demonstrate the masses as hyper- or isointense signals in the brain.