Our Providers
Nadyha Schumacher, Licensed Aesthetician
Janice Christen, Licensed Aesthetician
Mary Fredenberg, M.D. <back to top>
I began my Dermatology practice in 1986 after completing my residency in Chicago, Illinois and moving back home to Phoenix, AZ. I am the oldest of seven children, who with my parents, consider Phoenix our home. I was raised in Syracuse, NY, however one winter in Phoenix is enough to change a person’s mind. I have a passion for Dermatology because it satisfies my desire to diagnose and treat disorders that you can “see”, it allows me to meet the most interesting people and it affords me the opportunity to learn of countless new scientific advances. I have had the distinct pleasure of being able to surround myself with wonderful colleagues, a staff who is very devoted to the caring of each individual patient, and the excitement that each day brings to the delivery of very high quality care of the skin, whether it is medical or cosmetic based.
BS Microbiology 1978
Arizona State University
Tempe, AZ
Medical School 1982
University of Arizona
Tucson, AZ
Internal Medicine internship 1983
Good Samaritan Medical Center
Phoenix, AZ
Dermatology residency 1986
Rush-Presbyterian-St. Luke's Medical Center
Chicago, IL
Board Certified by the American Board of Dermatology 1986
Theresa Magne, M.D. <back to top>
I am the second child out of seven and one of five doctors in my Chicago raised family. I dreamed of moving to Arizona since I was a teenager and have been passionate about dermatology since my first lecture 20 years ago. After completing my medical education in July of 1995, I was fortunate to join Dr. Mary Fredenberg in our Thunderbird, four patient exam room office. With our goal of hiring compassionate staff and determination to practice quality dermatology, we have grown larger than I ever anticipated. I practice both general and cosmetic dermatology. My two greatest areas of interest are cancer skin screens and cosmetic procedures; Botox, fillers and lesion removals.
Medical School
University of Illinois College of Medicine, May 1991
Rockford, Illinois
Internship
Internal Medicine 1991-1992
Loyola University Medical Center Maywood, Illinois
Dermatology 1992-1995
Rush-Presbyterian-St. Luke's Medical Center
Chicago, Illinois
Board Certified in Dermatology , American Board of Dermatology, October 1995
Re-certification Exam in Dermatology, American Board of Dermatology, 2004.
Jill West, PA-C <back to top>
Jill is a board certified Physician Assistant, completing her graduate and undergraduate studies from Midwestern University, Glendale, AZ. She earned a Bachelors of Science in Physician Assistant Studies and in Biomedical Science. While completing her education at Midwestern University, she was awarded the Academic Excellence award. Jill was added as a member of North Valley Dermatology team in 2006.
Lisa Greenan, PA-C <back to top>
Lisa Greenan earned her Bachelor of Science in Biology/Psychology at Union College, Schenectady,NY in 1990. After working as a research assistant studying Alzheimer’s disease at Massachusetts General Hospital in Boston,MA, she became interested in pursuing a career in medicine. She obtained her Masters in Health Science at Duke University, NC in 1994. Her first experience was in family practice and after a few years she moved into dermatology. Lisa joined North Valley Dermatology in September of 2007 and has experience in both general and surgical dermatology. Lisa is an active member of the SDPA (Society of Dermatology Physician Assistants). She lives in the NW valley with her husband and three beautiful children
Tara Walker, MS, PA-C <back to top>
Tara graduated summa cum laude and salutatorian of her class from Sacred Heart University in Fairfield, CT where she obtained a Bachelor of Science degree in biology. She went on to graduate at the top of her class with high honors from Baylor College of Medicine in Houston, TX where she received a Master of Science degree and became certified as a physician assistant. Tara is board certified by the National Commission on Certification of Physician Assistants. She holds professional memberships in the American Academy of Physician Assistants and the Society of Dermatology Physician Assistants. She practiced pediatric medicine as an assistant professor at Texas Tech University prior to joining North Valley Dermatology in 2007. Tara is trained in all aspects of medical dermatology. She loves treating children, as well as adults, and looks forward to improving the health of your skin.
Janice Christen, Licensed Aesthetician <back to top>
Janice Christen is an Arizona native who has worked in the medical field for over 30 years initially as a back office Medical Assistant. Her passion and curiosity for skin care and working with people sent her back to school for her Aesthetics license. She has advanced training in Chemical peels, Lam Probe, Microdermabrasion, PDT-Levulan and Foto facial treatments. She is passionate about her work with medical and professional grade treatments and home care allowing her to obtain great results and healthy glowing skin. Her goal is to customize treatments to improve skin health while achieving patient goals.
Deborah Zell, M.D. <back to top>
Dr. Deborah Zell, MD joined North Valley Dermatology in the fall of 2010. She is a board certified and fellowship trained dermatologist who specializes in Mohs Micrographic Surgery and Procedural Dermatology.
Dr. Zell was born in New Orleans, LA and grew up in South Florida. After high school, she moved back to New Orleans for college and graduated from Tulane University with the honors of Summa Cum Laude and Phi Beta Kappa. She earned double majors in Mathematics and Chemistry during her undergraduate education, and served as President of her undergraduate student body. She also received the prestigious President’s Award during her undergraduate studies.
Following her undergraduate education, Dr. Zell attended the Tulane University School of Medicine. She then completed an Internal Medicine internship in New Orleans, training at Charity Hospital, University Hospital, Tulane University Medical Center and the Veterans Affairs Hospital.
Dr. Zell then moved to Miami, and served as a clinical research fellow at the University of Miami in the Department of Dermatology and Cutaneous Surgery where she initiated, managed, and conducted fourteen clinical trials, focusing primarily on scarring and keloids.
Dr. Zell also completed her dermatology residency training at the University of Miami, where she cared for a diverse and international patient population. During this time, she excelled in clinical research, dermoscopy of pigmented lesions, and skin cancer surgery. As a result of her achievements, she was awarded the revered Surgical Award and the prestigious Kramer Research Award two years in a row at the University of Miami.
Dr. Zell then completed a highly sought after Mohs Micrographic Surgery Fellowship in New York under the guidance of Dr. Daniel Siegel, the 2011-2012 President of the American Academy of Dermatology, and renowned Mohs and dermatologic surgeon. During her fellowship, Dr. Zell performed surgery at the State University of New York (SUNY) – Downstate, the Veterans Affairs Harbor Hospital in Brooklyn, and in private practice on Long Island. She also gave lectures to the dermatology department at SUNY Downstate during this time.
Dr. Zell is highly trained and skilled in the surgical treatment of skin cancer, and serves as dermatologic surgeon, pathologist and reconstructive surgeon in her practice. She has also worked in private practice as a dermatologic surgeon in New York City, and has served as a guest lecturer on various dermatologic conditions and therapies on a national level. Dr. Zell has also authored numerous dermatologic articles and textbook chapters as well as served as a peer reviewer for other medical authors.
She is an active member of the Women’s Dermatologic Society, the American Academy of Dermatology, and the American Society for Dermatologic Surgery.
Dr. Zell currently resides in Scottsdale, Arizona with her husband and two young children. During her time outside of the office, she enjoys spending time with her family and friends, baking and exercising.
Trevor Thompson, M.D. <back to top>
Dr. Trevor Thompson joined North Valley Dermatology in 2011. He is dedicated to providing quality personalized care for his patients with both acute and chronic conditions. He has experience in wide variety of skin conditions and skin types. His areas of specialty include dermatologic surgery, Botox/Dysport, fillers, acne and psoriasis.
Dr. Thompson arrives to North Valley Dermatology from Hawaii where he worked at the Kauai Medical Clinic from 2005 to 2011.
Dr. Thompson was Clinical Instructor at Harvard University from 2002 to 2005 where he taught residents, medical students and international fellows training in dermatology. He was also Chief Dermatologist for the Cambridge Health Alliance in Cambridge, Massachusetts, a teaching hospital for Harvard Medical School.
Dr. Thompson completed his medical degree, internship and residency at the University of Kansas where he served as Chief Resident for Dermatology. He also received a BS in Chemical Engineering from the University of Kansas.
Dr. Thompson is a Fellow of the American Society of Dermatology Surgery and the American Academy of Dermatology. He is Board Certified by the American Board of Dermatology.
Julie Taubert, PAC <back to top>
Julie graduated Suma Cum Laude from the Barret Honors Society at Arizona State University where she obtained a Bachelor of Science degree in Biology and a minor in Spanish. She continued her education at Midwestern University Glendale campus where she received a Masters of Medical Science degree in Physician Assistant Studies. She is board certified by the National Commission on Certification of Physician Assistants. She holds professional membership to the Society of Dermatology Physician Assistants, American Academy of Physician Assistants and NCCPA. At midwestern she was President of her graduating class and had fund raisers for numerous organizations. She was also the president of Phi Eta Sigma and a member of Phi Beta Kappa. She joined North Valley Dermatology in 2009. She has training in medical, surgical and cosmetic dermatology.
Nadyha Schumacher, Licensed Aesthetician <back to top>
Nadyha Schumacher developed her passion with skin care while working with a Dermatology practice in Orange County, California where she aided patients in post-operative skin care, laser treatments, chemical peels, and medically based facials. She quickly realized her goal was to become an aesthetician and educate others about the importance of skincare. In 2004, Nadyha earned her Arizona state aesthetician license. Today she looks forward to always being able to provide the epic results her clients expect and deserve.