For Physicians. By Physicians.™

FREE weekly ObG Insider NewsletterClick here

Endometrial Hyperplasia – Current Nomenclature and Treatment


Endometrial intraepithelial neoplasia (EIN) is the precursor of type I endometrioid adenocarcinoma. Distinguishing between hyperplasia and a precancerous lesion is important in optimizing management. 

Disease Categories  

  • Benign endometrial hyperplasia (benign), a diffuse condition due to prolonged estrogen effect 
    • Treatment is hormonal therapy 
  • Endometrial intraepithelial neoplasia (EIN) 
    • Premalignant 
    • Focal abnormality progressing to diffuse involvement  
    • Treatment can be hormonal therapy or surgery 
  • Endometrial adenocarcinoma, endometrioid type, well differentiated (malignant), a focal abnormality progressing to diffuse 
    • Treatment is surgical 

Note: the above is the system developed by the International Endometrial Collaborative Group | Other classification systems exist and ACOG does not endorse a particular EIN classification system

Criteria Used for diagnosing EIN 

  • Architectural change with area of glands greater than stroma 
  • Cytologic abnormality in area of architectural change 
  • Size of abnormal area  
  • Not a polyp, area of repair, secretory endometrium (excludes mimics) 
  • Not carcinoma (excludes cancer) 

Detecting Concurrent Carcinoma  

  • Risk of endometrial cancer in hysterectomy specimens is 30% to 50%   
  • Methods for Detecting Concurrent Carcinoma  
    • Hysteroscopic-guided uterine sampling is recommended for diagnosis  
    • In-office suction endometrial sampling may miss pathology  
  • Avoid methods yielding crushed or cauterized samples  

Surgical Management of EIN  

  • Hysterectomy is the definitive treatment   
  • Supracervical hysterectomy is not advised   

Considerations for Oophorectomy  

  • Oophorectomy decision should be patient-centered, weighing risks and benefits  
  • Intraoperative assessment for occult carcinoma may guide surgical decisions  

Intraoperative Assessment  

  • Assess uterine specimens for occult carcinoma   
  • Assessment should be directed by qualified pathologists and experienced surgeons  
  • Consultation with a gynecologic oncologist depending on clinical scenario and availability   

Morcellation – Proceed with Caution 

  • If morcellation is required, use a contained environment such as a bag   
  • Note that morcellation can affect pathology evaluation   

Endometrial Ablation  

  • Not recommended   
  • High persistence | Increased recurrence rates | May complicate evaluation of future bleeding episodes  

Nonsurgical Management of EIN 

Progestational Agents 

  • Recommend progestational agents for patients not suitable for hysterectomy  
  • LNG-IUD vs Oral Progestins  
    • Data on the superiority of administration methods are limited  
    • LNG-IUD may have a higher regression rate compared to oral progestins alone  
    • Combined intrauterine and oral progestins may be more effective  
  • Oral Progestin Formulations  
    • No evidence favors one oral progestin formulation over another  
    • Megestrol acetate or medroxyprogesterone acetate are commonly used  
  • Follow-up  
    • Repeat histologic assessment within 3 to 6 months for treatment response  
    • Long-Term Maintenance Therapy  
    • Consider long-term progestational agent maintenance for high-risk patients  
    • Consider risk factors (e.g., age, late menopause, and obesity)  
    • Optimal duration of maintenance therapy remains uncertain  

Future Fertility  

  • Fertility-sparing therapy may be an option with assisted reproductive technology  
  • Pregnancy rates range from 26.3% to 41.0% with progestational agents  
  • Active management for achieving pregnancy should be discussed  

Counseling on Lifestyle Modifications  

  • Weight Loss and Glycemic Control  
  • Obesity is a significant risk factor   
  • Lifestyle modification with weight loss and glycemic control improves overall health  
  • Bariatric surgery can be an appropriate intervention among selected patients  
  • Weight loss can enhance the response to progestin treatment  
  • Telemedicine and Text-Based Interventions  


  • The EIN system appears to increase reproducibility and reduce subjective, descriptive interpretation of pathology 
  • Hysteroscopy with directed biopsy of any discrete lesions is the best way to confirm a premalignant endometrial lesion and to exclude endometrial carcinoma 
  • Both suction curettage and dilation and curettage have significant sampling limitations 
  • Hysterectomy is the definitive therapy for EIN: Abdominal, vaginal or minimally invasive, with or without removal of fallopian tubes and ovaries 
    • Supracervical hysterectomy is contraindicated 
    • Endometrial ablation should not be performed due to high recurrence rates and difficulty evaluating bleeding etiologies 
  • Medical treatment, using progestins, can be offered to patients who wish to retain fertility, desire uterine retention, or have multiple medical comorbidities 
    • Medroxyprogesterone acetate and megestrol acetate are most commonly used 
    • The 52 mg levonorgestrel containing IUD provides another option 
    • Regression rates approach 90% with any of the above 
  • Discussion of lifestyle changes particularly in the setting of obesity can be a part of management with shared decision making  
  • Telemedicine and text-based interventions can assist patients with weight loss  

Learn More – Primary Sources 

Management of Endometrial Intraepithelial Neoplasia or Atypical Endometrial Hyperplasia | ACOG