Providers

Dr. Greg Seitz

Seeing patients at our Cheyenne, Timnath, and Wellington locations.

Dr. Greg Seitz, board certified dermatologist and Mohs surgeon, brings a wealth of expertise and a passion for dermatology to his practice. With degrees in Zoology and Psychology from the University of Wyoming, Dr. Seitz pursued and earned his Doctor of Medicine in 2007 at Oregon Health and Science University.

In 2011, he completed his specialty residency training at the University of Colorado, where he honed his skills in medical, surgical, and cosmetic dermatology, alongside dermatopathology and Mohs surgery.

Along with his commitment to his patients, Dr. Seitz has also worked as a teaching physician for the University of Wyoming Family Medicine Residency Program since 2011. Additionally, he is a member of the following esteemed medical associations:

• American Academy of Dermatology
• American Medical Association
• American Society for Dermatologic Surgery
• American Society for Mohs Surgery
• Colorado Dermatologic Society
• Laramie County Medical Society
• Wyoming Medical Association
• Wyoming Medical Society

A native of Cheyenne, Wyoming, Dr. Seitz’s roots run deep in the community where he was born and raised. Alongside his wife and three children, he embraces the Wyoming lifestyle, indulging in outdoor pursuits like fishing, camping, hiking, and skiing whenever possible.

Tamara Mason, DNP, FNP-C

Seeing patients at our Cheyenne location.

Bachelor of Science in Nursing from University of Wyoming • Doctor of Nursing Practice from University of Wyoming • Board-certified Family Nurse Practitioner by American Association of Nurse Practitioners • Member of Sigma Theta Tau • Member of American Association of Nurse Practitioners

Driven by a desire to provide high-quality, evidence-based care, Tamara (“Tami”) Mason earned her doctoral degree from the University of Wyoming and became a nurse practitioner. She brings more than two decades of nursing experience in both inpatient and outpatient settings to her practice here at Seitz.

A Wyoming native, Tami grew up on a ranch near Yoder, then settled in Cheyenne with her husband to raise their three daughters. Together with her family, Tami enjoys camping, hiking, and taking in all types of sporting events at the University of Wyoming. In her spare time, she also enjoys traveling, reading, and playing in two bell choirs at her church.

Colleen Basham, MSN, APRN, FNP-C

Seeing patients at our Timnath and Wellington locations.

Bachelor & Master of Science in Nursing from Regis University • Board-Certified Family Nurse Practitioner by American Academy of Nurse Practitioners • Member of American Association of Nurse Practitioners

Colleen Basham is a certified nurse practitioner, specializing in dermatology. After five years working in an all-natural spa, she was inspired to pursue a nursing degree at Regis University where she graduated with honors. She then went on to work in cardiology, internal medicine and public health before returning to Regis University for her nurse practitioner degree. With a range of medical experience under her belt, Colleen has found her way back to her original love – skincare. Having struggled with her own skin issues over the years, she is forever passionate about helping others feel truly confident in their skin.

As an Austin native (that’s right, y’all), she considers Colorado home after almost two decades in Northern Colorado. When not exploring all things skincare, Colleen loves to take advantage of everything Colorado has to offer, adventuring with friends and her loyal pup, Althea. She is honored to be part of the Seitz Dermatology team, excited to connect with the Wellington community and eager to start helping patients reach their skin health goals.

Shelley Johnson, FNP-C

Seeing patients at our Cheyenne location.

Bachelor of Science in Science and Minor Psychology from University of Wyoming • Bachelor of Science in Nursing from Creighton University • Master of Science in Nursing from Gonzaga University • Psychiatric-Mental Health Nurse Practitioner (PMHNP) Certification from University of Wisconsin Madison.

Shelley Johnson is a versatile nurse practitioner with 16 years of diverse experience in family practice. Driven by her genuine passion for skincare, she is dedicated to comprehensive patient wellness, and her clinical background enhances her specialized care in dermatology and medical weight loss management. 

Outside of work, Shelley enjoys hiking, snowboarding, yoga, traveling, and spending time on the family ranch. Her greatest joy is sharing outdoor adventures with her son and her trusty pup, Bronco.