Study of Mast Cell Distributionin Uterine Smooth Muscle Tumours

Abstract

Uterine smooth muscle tumors (SMTs) constitute a heterogeneous group of neoplasms ranging from benign leiomyomas to malignant leiomyosarcomas, with smooth muscle tumors of uncertain malignant potential (STUMP) representing an intermediate and diagnostically challenging category. Although traditional histopathological parameters such as cytological atypia, mitotic index, and tumor cell necrosis remain central to classification, increasing evidence highlights the critical role of the tumor microenvironment in influencing tumorbehavior. Among immune components of the stromal milieu, mast cells have emerged as key modulators of inflammation, angiogenesis, extracellular matrix remodeling, and immune regulation.

This narrative review synthesizes evidence from eleven published studies between 2015 and 2025 to evaluate mast cell distribution, density, detection methods, and pathological significance across uterine leiomyoma, STUMP, and leiomyosarcoma. The reviewed literature consistently demonstrates increased mast cell infiltration in leiomyomas, often localized around blood vessels and fibrous stroma, suggesting a role in tumor growth and angiogenesis. In contrast, STUMP exhibits variable and heterogeneous mast cell distribution, reflecting its uncertain biological behavior. Leiomyosarcomas generally show reduced mast cell density compared to benign counterparts, correlating with poor differentiation and aggressive clinical course.

Collectively, these findings indicate that mast cell distribution patterns differ significantly across the spectrum of uterine smooth muscle tumors and may serve as supportive indicators of tumor differentiation and biological potential. Understanding the interaction between mast cells and neoplastic smooth muscle cells enhances insight into tumor biology and underscores the importance of the tumor microenvironment in gynecologic pathology. Further standardized, large-scale studies integrating immunohistochemistry and molecular analysis are warranted to clarify the diagnostic and prognostic relevance of mast cells in uterine smooth muscle tumors.