For a month, an 88-year-old woman saw things that frightened her. She lost track of recent events, drifted away from hobbies and family, and became intermittently disoriented. Her daughter noticed the change first. She had been living independently and had screened negative for depression multiple times before.
The cause turned out to be leukemia growing in the septum pellucidum, a thin sheet of tissue separating the two lateral ventricles of the brain, five years after her cancer went into remission. Reviewing the indexed literature, the authors found no previously documented case of an isolated myeloid sarcoma arising strictly from that structure.
