PMC10302693_01
A vaginal mass is typically a soft, edematous, polypoid botryoid mass (A). Polypoid fronds of the botryoid form are typically seen on histological imaging (B). The cambium layer (subepithelial condensation of stroma) is present (C, HE x 200). The strap-shaped rhabdomyoblasts have eosinophilic cytoplasm with cross-striations (D, HE x 400) and positive nuclear staining for myoD1 (E) and myogenin (F). A giant mass (arrow) occupied the whole vaginal cavity and extended downwards to the vulva (arrowhead). The mass is mainly displayed as an isointense signal on both T
1WI (G) and T
2WI (H). The tiny small cysts were seen within the lesion. The tumor did show a restricted signal on DWI (I) and ADC map (J). The sagittal (K) and coronal (L) T
2WI more clearly showed the contour of the mass. On post-contrast images (M), the tumor enhanced similarly to the normal uterus. The final pathology was RMS in a 15-year-old girl. ADC, apparent diffusion coefficient; DWI, diffusion-weighted imaging; RMS, rhabdomyosarcomas.
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F10
Immunoreactivity of desmin and more specifically, skeletal muscle markers (myoglobin, myogenin, myoD1) facilitate the diagnosis (Figure 10A-F).
Low-power view shows sheets of large malignant melanocytic cells underneath the epidermis (A, HE x 40). Pleomorphic epithelioid melanocytic cells, irregular nuclear contour, conspicuous nucleoli, and mitotic figures are more commonly observed on the high-power view of the slide. Cytoplasmic melanin was focally present (B, HE x 400). Lentiginous in situ malignant melanoma with pagetoid spread component involves basal layers of the vaginal squamous mucosa (C, HE x 400). Melanocytic cells show positive stains for both HMB45 (D) and Melan-A staining (E, HE x 200). A giant mass (arrow) occupied the whole vaginal and vulvar area with a homogeneous isointense signal on both T
1WI (F) and T
2WI (G). The enlarged nodes (arrowhead) were seen on both the bilateral pelvic wall (G) and piriformis space (H). The mass showed moderate enhancement (I-J) after contrast injection. The final histological diagnosis was vulvar melanoma in a 54-year-old female.
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F11
Heterogeneous enhancement is often observed on MRI of RMS (Figure 11G-M), in which hemorrhage or calcification are not common signs.    Immunoreactivity of S100, SOX10, HMB45, and Melan-A (MART1) facilitates the diagnosis (Figure 11). Amelanotic melanoma of the vagina may be mistaken for other primary vaginal malignancies (Figure 11F-I, Supplementary Fig.5).