Intravascular papillary endothelial hyperplasia within the uterine myometrium: a case report and literature review.

Intravascular papillary endothelial hyperplasia (IPEH) is a rare vascular lesion that can histologically mimic malignant vascular tumors, particularly angiosarcoma, often leading to misdiagnosis and overtreatment. IPEH involving the uterine myometrium is a novel finding. We describe an 83-year-old postmenopausal woman presenting with a 6-day history of spontaneous vaginal bleeding. Pelvic examination revealed a patent vagina with minimal dark red blood and an enlarged, anteverted uterus. Pelvic magnetic resonance imaging showed a well-demarcated, heterogeneous intramural lesion (6.0 × 5.5 × 5.0 cm) in the right anterior uterine wall. Based on comprehensive imaging findings and clinical presentation, the preoperative differential diagnosis included possible sarcomatous transformation of a uterine leiomyoma versus endometrial carcinoma. The patient underwent total laparoscopic hysterectomy, bilateral salpingo-oophorectomy, and pelvic adhesiolysis. Gross examination revealed a well-circumscribed intramural cystic lesion. Histopathology demonstrated a collagenous cyst wall with residual smooth muscle, luminal organizing thrombus, and papillary structures lined by plump endothelial cells. Immunohistochemistry showed strong positivity for cluster of differentiation (CD)31 and ETS-related gene, focal positivity for CD34 and D2-40, negative hormone receptors (estrogen receptor/progesterone receptor), and a Ki-67 index of 20%. Histopathological examination confirmed a diagnosis of IPEH, a rare benign entity characterized by reactive endothelial proliferation. Complete surgical excision resulted in resolution of vaginal bleeding. At an 18-month telephone follow-up the patient was asymptomatic, and had received no adjuvant therapy, and pelvic ultrasonography demonstrated no evidence of recurrent disease. In conclusion, IPEH cannot be reliably distinguished from malignant vascular or uterine neoplasms based on preoperative clinical, imaging, or gross findings. Accurate diagnosis of this rare entity is contingent upon histopathological examination and immunohistochemical analysis. Awareness that IPEH can occur within the uterine corpus may facilitate its inclusion in preoperative differential diagnosis, thereby potentially improving diagnostic precision and alleviating patient anxiety associated with the suspicion of malignancy.