A 19-year-old woman in Colombia had been living with seizures for about four years when her symptoms took a turn. A severe, throbbing headache set in, and doctors found swelling at the back of one eye and a loss of vision on one side. An MRI then revealed a mass 8.3 centimeters across inside the right half of her brain, and her doctors' leading suspicion was a high-grade glioma, one of the most aggressive kinds of brain cancer.
It was not cancer. After surgeons removed the mass, pathologists identified a calcifying pseudoneoplasm of the neuraxis, or CAPNON, a rare noncancerous lesion made largely of fibrous tissue and calcium deposits. Pathologists at Universidad del Valle and Hospital Universitario del Valle Evaristo García in Cali described the case in the Revista Española de Patología, in the journal's July to September 2026 issue. The authors say the case stands out for its unusually large size and for the gap between what the scans suggested and what the tissue showed.
