Neurocysticercosis: This condition, caused by the pork tapeworm Taenia solium, can lead to brain lesions and is a common cause of seizures and other neurological symptoms in endemic areas. Fever can occur due to the body's inflammatory response to the dying parasites.

Brain Abscess: A collection of pus in the brain, usually caused by bacteria or fungi, which can present with fever, headache, and focal neurological deficits. The presence of brain lesions increases the likelihood of this diagnosis.
Toxoplasmosis: Especially in immunocompromised patients, toxoplasmosis can reactivate and cause brain lesions. Fever, along with neurological symptoms, can be part of the presentation.
Tuberculoma: A form of tuberculosis that affects the brain, presenting as a mass lesion. Fever, along with other systemic symptoms of tuberculosis, can be present.

Herpes Simplex Encephalitis: Although it typically presents with more acute symptoms like confusion, altered mental status, and seizures, fever can be an accompanying symptom. Missing this diagnosis can lead to severe consequences, including death.
Cerebral Malaria: In patients from or traveling to endemic areas, cerebral malaria can cause fever, coma, and brain lesions due to Plasmodium falciparum infection. It's critical to consider this in the differential due to its high mortality rate if untreated.
Brain Tumor with Infection: Primary or metastatic brain tumors can become infected, leading to fever and worsening neurological symptoms. This diagnosis is crucial to consider due to the implications for treatment and prognosis.

Whipple's Disease: A rare, systemic bacterial infection (Tropheryma whipplei) that can involve the central nervous system, presenting with fever, weight loss, and neurological symptoms.
Subacute Sclerosing Panencephalitis (SSPE): A rare chronic, progressive encephalitis that affects primarily children and young adults, caused by a persistent infection with the measles virus. It presents with a variety of neurological symptoms and can include fever in its early stages.
Progressive Multifocal Leukoencephalopathy (PML): A rare and often fatal viral disease caused by the JC virus that affects the brain and occurs in people with weakened immune systems. While fever is not a primary symptom, it can occur, and the disease leads to progressive damage to the white matter of the brain at multiple locations.