Contributed by P. Diamandis1, D. Amato2, J. Finkelstein3, and J. Keith1
1 Department of Anatomical Pathology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
2 Department of Medicine, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
3 Division of Orthopaedic Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
A 79-year-old man presented with a two month history of worsening back pain, urinary dysfunction and bilateral leg weakness. His past medical history included a childhood diagnosis of a metabolic disorder, which over the course of his life had manifested with hepatosplenomegaly, bone pain and osteoporosis. Seven years ago he was also diagnosed with prostatic carcinoma that had been managed conservatively. More recently he developed cognitive dysfunction and Parkinsonism and was awaiting neurocognitive assessment.
On neurological exam he was alert but mildly cognitively impaired with some Parkinsonian signs. Motor examination uncovered increased tone, hyperreflexia, clonus and significant weakness in his lower limbs (unable to overcome gravity). His sensory exam showed bilateral lower extremity loss of vibration sense.
MRI of the spine showed widespread signal change in the bone marrow and a pathologic compression fracture of L1 with retropulsion of the posterior aspect of the vertebral body into the anterior spinal canal compressing the cord at the level of the conus (Figure 1). He underwent L1 laminectomy, vertebrectomy and cord decompression with vertebroplasty. Intraoperatively the resected vertebral body appeared abnormal, and was sent to pathology labelled 'query metastatic carcinoma'.
Hematoxylin and eosin staining of the submitted specimen showed numerous bony spicules. In between the spicules there were no hematopoietic or adipose elements, but rather a sea of large eosinophilic cells (Figure 2), not reminiscent of carcinoma. Higher magnification of the lesional cells showed abundant unusually vacuolated cytoplasm and peripherally placed oval monomorphous nuclei (Figure 3). CD68 and Periodic acid-Schiff staining were strongly positive in these cells (Figures 4, 5).
What is the diagnosis?
What is the potential relationship between this diagnosis and the patient's other neurological symptoms?