Distribution of Mast Cells in Uterine Leiomyoma: A Hospital-Based Observational Study

Introduction Mast cells are immune cells of the myeloid lineage present in connective tissues that regulate various physiological processes. The human uterus is relatively rich in mast cells. Uterine fibroids are the most common benign tumors, originating in the myometrium. However, there is no consensus regarding the prognostic role of mast cells in the uterus. Hence, further study is necessary for clarifying the relationship between the distribution of mast cells and various conditions of the myometrium. Aims and objectives The objective of this study was to quantify mast cell density in uterine leiomyomas compared with adjacent myometrium and to evaluate its association with tumor location, patient age, and degenerative changes. Materials and methods This was a retrospective and observational study conducted from January 2019 to December 2021 in the Department of Pathology, Jawaharlal Nehru Medical College, KAHER, Belagavi. Tissue blocks of hysterectomy patients operated for uterine leiomyoma, a total of 100 cases, formed the source of data. Two sections each were taken from the leiomyoma and its adjacent myometrium, processed routinely, and stained with hematoxylin and eosin and 1% toluidine blue. The mast cells were counted under 40× magnification for 10 consecutive fields in each slide. Results Leiomyomas showed a perimenopausal age preponderance, and 59% were intramural in origin. A statistically significant inverse association was observed between mast cell density and advancing age in leiomyomas. Compared to the adjacent myometrium, uterine leiomyomas demonstrated an approximately twofold increase in mast cell counts. Additionally, leiomyomas with degeneration were associated with lower mast cell counts. Conclusions Progressively decreasing mast cell counts were observed as we moved from the uterine leiomyoma to the adjacent normal myometrium. Leiomyomas with degeneration were characterized by a significantly lower mast cell density.