Clinicopathological Characteristics of Ovarian Sclerosing Stromal Tumor with an Emphasis on TFE3 Overexpression

Histopathological and immunohistochemical findings for ovarian sclerosing stromal tumors. A: At scanning power, the tumor consists of several relatively well-circumscribed nodules that are randomly embedded in the edematous or fibrous stroma, resulting in a pseudolobulated appearance. B: At low power, two hypercellular nodules (upper one-third and right lower corner, respectively) are separated by fibrous stroma. C: Variable-sized, irregular-shaped blood vessels are located within and adjacent to the hypercellular nodules and exhibit a staghorn-branching (hemangiopericytoma-like) vascular pattern. D: At medium power, the tumor tissue consists mainly of 2 cellular components: bland-looking, round, or polygonal cells and spindle-shaped cells. E: Several lutein cells (yellow circles) possess abundant eosinophilic or granular cytoplasm and small nuclei. Neither moderate-to-severe cytologic atypia nor atypical mitotic figures were identified. F: The hypocellular areas show fibrous stroma, that often undergoes hyaline degeneration, edema, and myxoid changes. G: The lutein cells display cytoplasmic inhibin-α immunoreactivity. H: TFE3 is localized within the nuclei of round or polygonal cells. I: CD31 immunostaining highlights the vascular endothelial cells. Original magnification: A, ×12.5, B-C, ×40; D, ×100; E, ×200, F, ×40, G-H, ×100, I, ×200.