Fig. 2

T2-weighted imaging (T2W1) displays slightly hyperintense signals within the mass, with multiple punctate and patchy areas of increased signal intensity observed (red arrow, A). Tumor is focally encased by fibrous pseudocapsules (B). In non-myxoid areas, tumor cells exhibit either an epithelial-like or spindle-shaped morphology, with biphasic cytoplasm, moderate cellular pleomorphism, prominent nucleoli, and a diffuse, sheet-like arrangement (C, D). In myxoid areas, epithelioid or spindle-shaped tumor cells proliferate in a loosely cohesive reticular or clustered manner (E, F). The tumor cells show diffuse positivity for MUC1 (G) and ER (H) but are negative for Keratin (I) and CD34 (J). SMARCB1 expression remains absent in all tumor cells (K, vascular reactivity used as an internal positive control). The Ki-67 proliferation index is approximately 15% (L)