Extramedullary hematopoiesis causing spinal cord compression with excellent durable response after radiation therapy: Case report and review of the literature.

Extramedullary hematopoiesis (EMH) is a rare occurrence in the setting of spinal cord compression. We report on a 72-year-old who was initially diagnosed with polycythemia vera (PV) which after approximately 15 years converted to myelofibrosis which confirmed on bone marrow biopsy. In 2016, he presented to our ED with clinical symptoms suggested of spinal cord compression at the T3-8 region. This was confirmed by MRI imaging. After a review of existing literature, it was elected to treat the affected area with radiation consisting of 15 fractions of 200 cGy. Within 10 days, the patient had begun to regain strength in the affected regions both motor and sensory. At the 2 month follow-up, he was symptom-free and imaging also showed a complete response. In January 2019, the patient again presented with clinical symptoms of spinal cord compression in the T10-12 area. Again, this was confirmed by MRI imaging. The same fractionation scheme was used and again the patient had a complete resolution of all symptoms both motor and sensory at the 1-month follow-up. Of interest is that during both the courses of treatment there was not a significant in any blood indices from baseline presentation. In the setting of EMH-causing cord compression, the use of radiation is warranted with excellent early response that appears durable. In addition, we present a review of the literature on this topic.

Low Dose Brain Irradiation Reduces Amyloid-ß and Tau in 3xTg-AD Mice.

We have previously reported that low doses of external beam ionizing irradiation reduced amyloid-ß (Aß) plaques and improved cognition in APP/PS1 mice. In this study we investigated the effects of radiation in an age-matched series of 3xTg-AD mice. Mice were hemibrain-irradiated with 5 fractions of 2 Gy and sacrificed 8 weeks after the end of treatment. Aß and tau were assessed using immunohistochemistry and quantified using image analysis with Definiens Tissue Studio. We observed a significant reduction in Aß plaque burden and tau staining; these two parameters were significantly correlated. This preliminary data is further support that low doses of radiation may be beneficial in Alzheimer's disease.