Track: Clinical Studies

Abstract:

Introduction: Morphea is an autoimmune fibrosing disorder characterized by localized thickening of skin and subcutaneous tissue due to excessive collagen deposition. While previous studies have demonstrated reduced/absent CD34 staining in the dermis, data on other immunohistochemical (IHC) markers and special stains remain limited. Objective: To characterize the IHC and special stain profile in morphea lesions and compare them with matched healthy controls. Methods: Skin biopsy blocks from three patients clinically and histologically diagnosed with morphea were selected. Each was matched by age, sex, and biopsy site to healthy controls in 1:1 ratio. Control samples were obtained from uninvolved margins of unrelated skin surgeries. IHC and special staining was performed for CD34, CD123, Factor XIIIA, smooth muscle actin (SMA), and Verhoeff-Van Gieson (VVG) and staining patterns were analysed. Results: In morphea samples, IHC studies showed near complete absence of dermal and subcutaneous interstitial staining with CD34, increased CD123-positive plasmacytoid dendritic cells within the deep dermis, increased Factor XIIIA-positive cells within the superficial dermis and increased dermal staining with SMA. VVG showed retained but compressed elastic fibers with a parallel arrangement within the dermis. In contrast, normal skin showed diffuse dermal CD34 staining, largely negative CD123, Factor XIIIA highlighted scattered dendritic cells within the dermis, and SMA highlighted dermal smooth muscles and vessel walls. VVG showed normal elastic fibers. Conclusion: Morphea lesions show characteristic IHC changes, including increased myofibroblasts (SMA+) and Factor XIIIA-positive dendritic cells. These findings deepen understanding of the pathogenesis of morphea and may aid future diagnostic and therapeutic strategies.

Setu Mittal

Affiliation

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(557) Update on immunohistochemical and special stain profile in morphea