A Cross-sectional Study of Mast Cell Distributions in Uterine Leiomyoma and its Adjacent Myometrium.

Abstract

Introduction: Mast cells, discovered by Paul Ehrlich, drive inflammation, angiogenesis, wound healing, fibrosis, and benign/malignant lesion development. Tumour-associated mast cells at peri- and intratumoral sites secrete histamine, tryptase, VEGF, TNF-α, TGF-β, and interleukins, exerting protumorigenic or antitumorigenic effects. In uterine pathology, they localise to myometrium and smooth muscle tumours, associating with smooth muscle cells, fibroblasts, and collagen. Their role in leiomyoma pathogenesis is debated, with conflicting protumorigenic versus suppressive evidence.

Materials and Methods: This prospective comparative study at ACS Medical College and Hospital, Chennai (Jan–Dec 2025), analysed 40 hysterectomy specimens. Paraffin sections were stained with H&E and toluidine blue; mast cells were counted per 10 high-power fields (40×) in leiomyoma versus adjacent myometrium.

Results: Seventy percent of cases occurred in the age group 41–50 years. Leiomyoma mast cell density (23.35 ± 17.84/10 hpf) was significantly lower than myometrium (41.13 ± 23.74/10 hpf; p < 0.001). Among 14 degenerated cases, 13 had hyaline (myometrial mean: 35/10 hpf) and 1 myxoid (20/10 hpf) degeneration.

Conclusion: Higher adjacent myometrial mast cells suggest they promote leiomyoma growth via the tumour microenvironment, aiding benign versus malignant distinction and identifying therapeutic/diagnostic targets.