Uterine adenosarcoma: a case-based review of the diagnostic features

Uterine (Müllerian) adenosarcomas are rare malignancies which account for 5% of uterine sarcomas. Most presentations are postmenopausal, and with early stage disease. This report highlights these entities' diagnostic features, namely having a neoplastic benign or mildly atypical epithelial component, and sarcomatous (often low-grade) stromal component. Architecturally, they resemble phyllodes tumour. Stromal projections are lined by benign or mildly atypical Müllerian-type epithelia. Heterologous elements may be present, or there may be sex cord-like differentiation. The stroma typically displays increased periepithelial cellularity (the characteristic ‘cambium’ layer) and a mitotic activity of two or more mitotic figures/10 high power fields. Immunohistochemical profile shows the stroma to be oestrogen receptor, CD10 and Wilm's tumour-1 positive, with strong immunoreactivity for P53 and Ki67 seen in cases with sarcomatous overgrowth, where CD10 and ER positivity is often lost.