**Question:** Decidual casts bleeding per vaginum suggestive of:

A. Endometrial cancer
B. Endometrial hyperplasia
C. Endometrial polyp
D. Endometrial infection

**Core Concept:**
Decidual casts are structures formed during pregnancy when decidual cells, derived from the endometrial stromal cells, detach from the endometrial wall and are secreted into the uterine cavity. These structures are commonly observed in pregnancy and can be detected during routine pelvic examination or through Papanicolaou (Pap) smear. If decidual casts are present in a non-pregnant woman, it may indicate an underlying pathology.

**Why the Correct Answer is Right:**
Decidual casts in a non-pregnant woman are indicative of endometrial hyperplasia. Hyperplasia refers to an abnormal increase in the number of endometrial cells, which can be due to hormonal imbalances or other factors leading to uncontrolled cell proliferation. When decidual casts are present in conjunction with endometrial hyperplasia, it suggests the presence of endometrial hyperplasia with atypia or even malignancy, such as endometrial cancer.

**Why Each Wrong Option is Incorrect:**

A. Endometrial cancer: While decidual casts can be present in endometrial cancer, they are not specific to cancer. Decidual casts can be seen in hyperplasia as well, making cancer the less likely option.

B. Endometrial hyperplasia: Although decidual casts can be present in endometrial hyperplasia, the presence of atypia or malignancy (as in endometrial cancer) is a more severe condition. Decidual casts in hyperplasia are less concerning compared to endometrial cancer.

C. Endometrial polyp: Decidual casts can be present in endometrial polyp, but they are typically associated with a solid mass, not as cast-like structures. Polyp formation is not linked to decidualization process.

D. Endometrial infection: Decidual casts are not associated with infections, as they are a result of decidualization, which occurs during pregnancy. Infections typically present with clinical symptoms like fever, pain, and discharge, and are usually accompanied by leukocytosis.

**Clinical Pearl:**

Decidual casts in the absence of pregnancy or in a non-pregnant woman can indicate potential endometrial hyperplasia or cancer, as described above. It is crucial for clinicians to consider these conditions when evaluating a patient presenting with vaginal bleeding, especially when no other obvious cause is found.

Additionally, the presence of atypia or malignancy in the context of decidual casts should prompt further evaluation, including endometrial biopsy and possibly imaging studies, to confirm the diagnosis, determine the stage of disease, and guide treatment planning.