Koilocytes containing enlarged and irregular nuclei, perinuclear halos, and coarse keratohyalin
granules may be found in the granular and upper spinous layers.
The granular layer is composed of keratinocytes with an array of filaggrin-rich keratohyalin
granules and lamellar granules packed with lipid bilayers.
Electron microscopy reveals abnormal keratohyalin
granules with poorly formed intracellular lipid lamellae in the stratum coneum.1 Prenatal diagnosis with chorionic villus sampling (CVS) and amniotic fluid cells analysis is advised in women with previous affected baby.
Through the process of terminal differentiation, SG KCs produce two membrane-circumscribed granules, keratohyalin
granules and lamellar bodies.
While papillary structures with hyperkeratosis and hypergranulosis are intensely observed in laryngeal verruca vulgaris, there are no significant granular cells and keratohyalin
granules in verrucous carcinoma.
Similar to classic BD, pagetoid BD always shows full-level involvement of the epidermis, scattered multinucleated tumor giant cells, keratohyalin
granules, single-cell keratinization, and intercellular bridges visible between pagetoid cells, while EMPD lesion contains pagetoid cells well demarcated from nearby epidermal cells, flattened basal layer, stratum corneum involved, acinar structures, and no intercellular bridge.
In epidermis, moderate to severe acanthosis, mild to severe hyperkeratosis, hydropic degeneration of keratinocytes and many koilocytes with variably sized keratohyalin
granules were observed.
In 2006, Irvine and McLean (7) studied the histology of normal and atopic skin and demonstrated that the skin in AD has a defective barrier, with an absence of filaggrin-containing keratohyalin
granules in the epidermal granular layer.