Brain metastases from asymptomatic adenocarcinoma of the pancreas: an autopsy case report.

Background: Brain metastasis from pancreatic cancer is extremely rare. Because pancreatic cancer usually has a rapidly progressive nature, the majority of affected patients die from primary lesions before exhibiting clinical signs suggestive of brain metastases.

Case Description: The patient was a 62-year-old man who developed generalized convulsion followed by right hemiparesis accompanied by decreased consciousness level. Computed tomography (CT) scan revealed multiple brain tumors with ring-like contrast enhancement. Stereotactic biopsy disclosed mucinous adenocarcinoma. A marked increase in the serum CA19-9 level was noted, but the patient did not exhibit any other signs of pancreatic disease. Repeated whole body CT scan and ultrasonography demonstrated no primary lesions. The patient died of multi-organ failure during chemotherapy combined with radiation for metastatic brain tumors. Autopsy revealed well-differentiated papillary adenocarcinoma in the pancreatic head and systemic metastases associated with tumor emboli were widely distributed in various organs.

Conclusion: This patient initially presented only with symptoms of neurologic disorder and no pancreatic symptoms. Moreover, repeated radiologic examinations did not reveal the primary lesion. We considered that the unusual clinical course in our patient may be partly explained by the autopsy findings: diffuse sclerotic changes of the pancreas without swelling. The present report suggests that undetected pancreatic cancer may have been the primary lesion classified as "unknown origin" in some cases of metastatic brain tumors.