O'Brien and Ryan, LLP - Attorneys at Law
Mary Kay Plyter-Eigner
Email: mplyter-eigner@obrlaw.com
Main: (610) 834-6223
Fax: (610) 834-1749
Assistant: Shannon Keen
Email: skeen@obrlaw.com
Main: (610) 834-6247

Mary Kay concentrates her practice in complex medical malpractice litigation, representing healthcare providers including hospitals, nursing homes, physicians, physician assistants, advanced practice nurses, registered nurses and healthcare support staff.  She draws upon her prior experience as a clinical nurse in various settings, including long term care, rehabilitation nursing, telemetry, and critical care, to dissect the underlying medical issues and strengthen the defense of her peers. 

Mary Kay also serves as an arbitrator in the Philadelphia Court of Common Pleas. 

Practice Areas:

Recent Representative Matters:

Named to Pennsylvania Super Lawyers:

  • 2013 (Rising Stars)
  • 2014 (Rising Stars)
  • 2015 (Rising Stars)
  • 2016 (Rising Stars)

Bar Admissions:

  • Pennsylvania, 2006
  • New Jersey, 2006


  • Widener University School of Law, Wilmington, Delaware, 2005, J.D.
    • Cum Laude
  • Excelsior University, Albany, New York, 1996, B.S.N.
  • Frankford Hospital School of Nursing, 1995, Diploma in Nursing

Professional Associations and Memberships:

  • The American Association of Nurse Attorneys
  • Philadelphia Area Society for Healthcare Risk Management
  • Philadelphia Bar Association
  • Montgomery County Bar Association

Hickory Pointe
2250 Hickory Rd, Suite 300
Plymouth Meeting, PA 19462
Phone: (610) 834-8800
Fax: (610) 834-1749