Simona Braun, MD

Mary Derlacki, FNP

Dr. Sarah Cassell is a Board Certified Rheumatologist. Her practice includes treatment of arthritis and the entire spectrum of rheumatic disorders from osteoarthritis to vasculitis. Sarah earned her BA degree, Phi Beta Kappa, at Wesleyan University in Connecticut. She earned her medical degree at Oregon Health and Science University and trained in internal medicine at Beth Israel Deaconess Medical Center in Boston, where she was a Harvard Medical School clinical fellow. Sarah trained in rheumatology at the University of California, San Diego. During this time, she was awarded a study fellowship from the Consortium of Rheumatology Researchers of North America.

Before returning to Eugene with her husband and son in 2011, Sarah practiced consultative and primary care rheumatology for three years. Sarah grew up in Eugene and enjoys the region's outdoor activities, biking, playing squash and snow skiing.


Mary has been a nurse practitioner in Oregon since 1990. She completed her undergraduate work at Seattle University and graduated with a Bachelor of Science in Nursing, cum laude. She is a member of Sigma Theta Tau, Honor Society of Nursing. She completed her Masters of Science in Nursing at University of Alaska, Anchorage. Upon arrival in Oregon, she worked for 12 years at the Junction City and Harrisburg Clinics doing Family Practice with an emphasis on rural medicine, urgent care and minor trauma.

In 2002 she joined Eugene Rheumatology where she received extensive training with Dr. Sidney Cassell. She co-manages patients with Dr. Sidney Cassell and Shirree Eberhardt, PA-C. Her scope of practice includes inflammatory arthritis, osteoporosis, osteoarthritis and gout. She has an interest in how diet, exercise and sleep influence health and healing.

In her off time she enjoys cycling, dancing, gardening, travel and spending time laughing with family and friends.  

Eugene Rheumatology

formerly Drs Cassell and Boren, PC

Shirree Eberhart is a certified Physician Assistant who specializes in Rheumatology. She earned her bachelor's degree at Boise State University, her Master of Science in Physician Assistant Studies and Master of Public Health degrees at Touro University California. She shares patients with Dr Sidney Cassell, Dr Sarah Cassell and Dr Simona Braun. Shirree grew up in Oregon and enjoys water sports, camping and backpacking.

Sidney Cassell, MD

Dr. Simona Braun is a Board Certified Rheumatologist. She has a particular interest in the treatment of rheumatoid arthritis and has enjoyed practicing in Eugene for over 15 years. She completed her residency and fellowship training in Albany, NY.

Dr. Sidney Cassell attended the University of Michigan earning a BS degree in Mathematics. He earned his medical degree at Washington University. Dr Cassell completed his internship and residency in internal medicine at UCLA followed by a fellowship in rheumatology at UCLA. Dr Cassell is board certified in internal medicine and rheumatology. His practice is limited to arthritis and rheumatic disease.

Shirree Eberhart, PA-C

Sarah Cassell, MD

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