Question

Which one of the following endometrial histopathological findings is suggestive of an ectopic pregnancy?

• A. Decidual reaction
• B. Chorionic villi
• C. Proliferative endometrium
• D. Secretory endometrium

Hint:

Look for decidua without any villi, that gap is the clue.

Answer 1

The Correct Option is A

Step 1: Recall what happens to the endometrium in a normal early pregnancy.
In an intrauterine pregnancy, rising progesterone converts the endometrium into decidua, and chorionic villi from the implanted embryo are found within that decidua on biopsy. Finding villi confirms that the pregnancy has implanted inside the uterine cavity.

Step 2: Think about what happens when the pregnancy is ectopic.
In an ectopic pregnancy, the embryo implants outside the uterus, so no chorionic villi are present in an endometrial sample. But the pregnancy hormones, beta hCG and progesterone, still act on the uterine lining through the bloodstream, so the endometrium still turns into decidua.

Step 3: Name this pattern.
Decidual change without any chorionic villi in the sample, sometimes with the Arias Stella reaction (glands showing hypersecretory, bizarre looking cells), is the classic histological clue that points toward a pregnancy growing outside the uterus.

Step 4: Rule out the other options.
Chorionic villi in the sample would confirm an intrauterine pregnancy, the opposite of what we are looking for. Proliferative endometrium reflects the estrogen driven phase before ovulation and is not linked to any pregnancy state. Secretory endometrium reflects the normal post ovulatory, progesterone driven phase and does not by itself point to pregnancy of any location.

Final Answer:
Decidual change in the endometrium, with no chorionic villi seen, is the finding that raises suspicion for ectopic pregnancy.
\[ \boxed{\text{Decidual reaction}} \]