Intravascular Endometrium Mimicking Vascular Invasion

Intravascular endometrium (IEM) is a rare finding that can pose a significant diagnostic dilemma, especially in cases of known carcinoma where the possibility of vascular invasion must be entertained. The distinction between IEM and intravascular invasion of malignancy can be made based on histologic findings and immunohistochemical profile. We report a case of IEM in a hysterectomy specimen removed from a 38 year old patient with invasive cervical adenocarcinoma and adenomyosis. Histologically, the lumen and intima of large muscular vessels contained well-developed glands with high nuclear to cytoplasmic ratio and endometrial stroma with spindled nuclei associated with hemorrhage and hemosiderin-laden macrophages. By immunohistochemistry, the benign glands within vascular spaces were positive for vimentin, ER and PR, but only rare cells were positive for p16. The stroma surrounding the intravascular glands was positive for CD10. These results confirmed the presence of IEM. The presence of IEM may be confused with vascular invasion which may affect staging and treatment of the patient.