Multimodal ultrasound imaging in the diagnosis of primary vaginal malignant melanoma: A case report

Rationale: Primary vaginal malignant melanoma (PVMM) is an extremely rare and aggressive gynecological malignancy with a poor prognosis. Early and accurate diagnosis is challenging, and conventional imaging modalities have limitations. This case report highlights the application value of a multimodal ultrasonographic approach for the preoperative assessment of PVMM. Patient concerns: A 48-year-old postmenopausal female with a long-term history of systemic sclerosis presented with a two-month history of vaginal bleeding and discharge. She reported a recent increase in discharge volume. Diagnoses: Gynecological examination revealed a firm, ulcerated mass on the posterior vaginal wall. Transrectal high-frequency ultrasonography, combined with multimodal techniques including three-dimensional ultrasound, superb microvascular imaging, shear-wave elastography, and contrast-enhanced ultrasound, characterized a hypoechoic mass with rich peripheral vascularity, specific stiffness patterns, and a “fast-in and fast-out” enhancement pattern. These findings were highly suggestive of malignancy, which was subsequently confirmed by biopsy and immunohistochemistry. Interventions: This report focuses on the diagnostic intervention, namely the comprehensive ultrasonographic evaluation using the aforementioned multimodal techniques. The patient underwent a biopsy of the vaginal mass for pathological diagnosis. Outcomes: The integrated multimodal ultrasound examination provided detailed structural, vascular, and functional information about the lesion, leading to a strong suspicion of malignancy that was pathologically confirmed as PVMM. Lessons: Multimodal ultrasonography, incorporating high-resolution imaging, microvascular assessment, elastography, and contrast enhancement, offers significant value in the diagnostic evaluation of PVMM. It can provide high-resolution anatomical details and quantitative functional data, potentially improving preoperative assessment and diagnosis of this rare tumor.