# Endometrial Adenocarcinoma After a Benign Biopsy Without Atypia: A Case Report

## TL;DR

A patient with a benign endometrial biopsy was later diagnosed with endometrial adenocarcinoma after a hysterectomy, highlighting the rare but significant risk of missing cancer in initial tests.

## Contribution

This case report highlights the rare occurrence of endometrial adenocarcinoma diagnosed post-hysterectomy despite a pre-operative benign biopsy.

## Key findings

- A pre-operative endometrial biopsy showed hyperplasia without atypia, but post-operative pathology revealed grade 2 invasive adenocarcinoma.
- The patient had a 36 mm endometrial stripe and hyperplastic appearance on imaging, yet cancer was not detected pre-operatively.
- Incidental diagnosis of endometrial adenocarcinoma after a benign biopsy is rare and has important clinical implications.

## Abstract

Endometrial biopsy is a highly effective screening procedure used to determine endometrial cancer and its precursors. This is often used to rule out endometrial cancer, the most common gynecologic cancer in the United States, before a total hysterectomy. This is a case of a benign endometrial biopsy that was ultimately malignant in the post-operative pathology report. A 37-year-old female presents with a six-month history of dysmenorrhea, passage of large clots, and pelvic pain, seeking definitive treatment with a hysterectomy. The pre-operative assessment included ultrasound, hysteroscopic exam, and endometrial biopsy. The ultrasound demonstrated evidence of adenomyosis due to the heterogeneous appearance of the myometrium and an endometrial stripe of 36 mm. Endometrial biopsy using pipelle was performed alongside an in-office hysteroscopic exam, which had a hyperplastic appearance of the endometrium. The biopsy resulted in hyperplasia without atypia and scant polypoid endometrial tissue. The patient underwent a total laparoscopic hysterectomy and bilateral salpingectomy without complications. The post-operative pathology report indicated a grade 2 invasive endometrial adenocarcinoma extending through 75% of the myometrium. Incidental diagnosis of endometrial adenocarcinoma following total hysterectomy is rare and poses significant medical implications. Endometrial hyperplasia without atypia has a low risk of progressing to endometrial carcinoma over time.