Transverse Myelitis. Patient, is a 78 y.o. male with a PMH of CML (2014) on nilotinib (2014-2019) in remission for the last 2 years.  Over the course of 1 month or so he has noticed unsteady gait then on 4/15 he had abrupt onset of left lower extremity weakness, MRI at outside hospital with new thoracic spinal mass, this was biopsied and revealed non-caseating granulomas. He was started on high-dose IVMP in the hospital but he only received 1 dose in the hospital as when he arrived to acute rehab they did not have IVMP and he only received 80mg prednisone and has been on slow taper since then, currently on 40mg prednisone. He has done well with improved strength in his lower extremities, improvement in sensory symptoms overall. Per ID, infectious process is still on the differential given that the biopsy specimen was not sent to microbiology; all of his ID workup in the hospital was negative to-date. ID recommended that if repeat resection/biopsy is done, we would recommend that a sample be sent to BOTH micro for aerobic/anaerobic/AFB/fungal culture as well as to path.   Given his clinical improvement on steroids and that he has not had paradoxical worsening of his symptoms if this were an infectious process, neurosarcoidosis may be more likely however, ACE (in serum and CSF) are soluble IL-2 receptor have been negative; in addition he had a full body PET with no e/o lung involvement. A repeat MRI T-spine was completed in July 2021 that showed marked improvement in the mass lesion at T1-T2 with reduction of spinal cord edeman previously present. Unfortunately, an MRI C-spine that I had ordered was not completed and an MRI L-spine was instead done. LP result were reviewed that again demonstrated no OCB's, normal nucleated cell, glucose and Protein 103 which is reduced compared to initial LP with Protein 165 on 5/24/2021. Notably, cytology was negative in CSF when repeated.  Given his clinical and radiographic improvement on steroids, and improvement of protein levels on CSF, neurosarcoidosis is the most likely diagnosis and has responded very well to immune suppression. Other work-up for myelopathies have been negative including NMO, MOG, HTLV, vitamin deficiencies. If there is radiographic worsening, will need to discuss with ID and neurosurgery indicatino for repeat spinal mass biopsy. Will continue prednisone taper as currently prescribed given his improvement.  Will plan to repeat MRI T-spine in early November 2021, obtain an MRI C-spine that was not completed. I have instructed the patient to continue slow prednisone taper  Transient thrombocytopenia, now resolved Discussed with ID, and was thought due to Bactrim ppx use in the setting of long steroid taper. This has now resolved. He reports he saw his hematologist and was re-tested for CLL which was negative. His cytopenias have resolved on most recent CBC on 7/28.  Severe Lumbar DJD with severe neuro foraminal narrowing throughout L-spine His recent MRI L-spine on my review looks to have severe NF narrowing at various spinal cord levels. I suspect that this may be contributing to the numbness/tingling he is experiencing in the left leg. I will ask his neurosurgeon to review this imaging.