A young man was seen at a neurologic center for a slowly progressive myelopathy involving the lower limbs in 1983. After examination and investigations, a diagnosis of chronic tuberculous spinal arachnoiditis was made and the patient was administered antituberculous treatment. However, his condition continued to deteriorate. He was reviewed at another center in 1985, where a diagnosis of demyelinating disorder was made, for which he was treated. However, this also did not help, and he was diagnosed as having a nonspecific spinal arachnoiditis at yet another center in 1988. His condition continued to worsen, and after ten years of symptoms, when magnetic resonance imaging (MRI) was done, an intramedullary cystic lesion opposite D-12 vertebrae was seen, which on histopathology was proved to be a vascular malformation. After excision of the lesion his neurologic status has been slowly improving. The conditions that a malformation could mimic, misleading a clinician, and the role of MRI in clinching the diagnosis are highlighted.