Ectopic decidua of pelvic lymph nodes: a potential diagnostic pitfall

Area of Science:

• Gynecologic Pathology
• Surgical Pathology
• Obstetrics

Background:

• Ectopic decidua, a benign lymph node inclusion, is increasingly reported, particularly in pregnant women.
• It is often found incidentally during postmortem examinations or in cases of cervical squamous cell carcinoma.
• Accurate identification is critical due to its potential for misdiagnosis as metastatic carcinoma.

Observation:

• This case involves a pregnant woman with cervical squamous cell carcinoma undergoing lymphadenectomy and hysterectomy.
• An intraoperative frozen section of a pelvic lymph node showed ectopic decidual change.
• This was mistakenly identified as metastatic carcinoma, highlighting a diagnostic pitfall.

Findings:

• Ectopic decidua in lymph nodes can histologically resemble metastatic carcinoma.
• Its location within subcapsular sinuses can contribute to diagnostic confusion.
• The rarity of this finding in routine practice increases the risk of misinterpretation.

Implications:

• Misdiagnosis of ectopic decidua as metastatic carcinoma can lead to unnecessary and potentially harmful treatment alterations.
• Distinguishing ectopic decidua from malignancy is essential for appropriate patient management.
• This case underscores the importance of thorough histological evaluation and awareness of benign mimics in lymph node pathology.