Doctors Suspect Brain Cancer, Discover Live Tapeworms in Man's Brain

Medical professionals initially believed a 60-year-old man was suffering from metastatic brain cancer after imaging studies showed numerous lesions. However, subsequent examinations unveiled a startlingly different diagnosis.

The patient, a resident of Castellón, Spain, whose identity was not disclosed, was found to have larval forms of a parasitic tapeworm lodged within his brain. This condition is identified as neurocysticercosis, a parasitic infection affecting the central nervous system caused by the pork tapeworm, Taenia solium.

Remarkably, the man had never traveled to areas where this disease is commonly found, as detailed in the case report published in the CDC journal Emerging Infectious Diseases.

A Challenging Diagnostic Journey

The man first sought medical attention after experiencing progressive headaches and subtle changes in behavior for two weeks. Initial CT scans revealed multiple abnormal spots resembling tumors, leading doctors to a preliminary suspicion of advanced brain cancer that had spread from another part of the body.

However, comprehensive full-body scans, a colonoscopy, and specialized imaging procedures failed to pinpoint any cancerous growth elsewhere in the patient's body, according to the case report.

Upon conducting a more advanced MRI, physicians identified several fluid-filled cysts in the brain, some of which distinctly contained the scolex, or head, of a tapeworm. A subsequent blood test definitively confirmed the diagnosis of neurocysticercosis.

The patient received treatment with a combination of two antiparasitic medications, albendazole and praziquantel, alongside corticosteroids to mitigate inflammation. He made a full recovery without any complications.

Understanding Neurocysticercosis and Transmission

The authors of the report theorized that the patient might have contracted the infection years earlier by inadvertently ingesting microscopic tapeworm eggs. This exposure could have occurred during his construction work, possibly through contact with migrant co-workers from regions where neurocysticercosis is endemic.

Humans can become infected with the pork tapeworm in two distinct ways. Consuming undercooked pork contaminated with tapeworm cysts typically results in an intestinal tapeworm infection. However, accidentally swallowing the parasite's eggs – usually via food or water tainted with fecal matter – allows the larvae to enter the bloodstream, where they can form cysts in the brain and other organs, leading to the severe condition observed in this case.

Since this was an isolated incident, researchers noted that the precise source of transmission could not be conclusively proven, and therefore, the findings cannot be generalized to a broader population. While the report suggests the potential for local transmission in areas not considered endemic, it does not establish the frequency of such occurrences.

In the United States, less than 2% of reported neurocysticercosis cases are believed to be domestically acquired. A prior systematic review from 1990 to 2011 identified only 18 confirmed locally acquired cases across Western Europe.

In some instances, neurocysticercosis can manifest with severe symptoms, including seizures, stroke, neurological impairments, and cognitive decline.

Implications for Diagnosis in Non-Endemic Regions