A) Cornoid lamella is a
histopathologic reaction pattern caused by abnormal keratinization.
The important features are:
1) Columns of parakeratotic cells.
2) Granular layer is absent. compare with
3) showing prominent granular layer.
B) It is the key histologic
feature of porokeratosis and its clinical variants.
The most important clinical
type of porokeratosis is porokeratosis of Mibelli.
It is an incidental finding in
a range of inflammatory, hyperplastic and neoplastic lesions.
Example : Seborrheic keratosis,
verruca vulgaris, actinic keratosis, squamous-cell carcinoma in situ (Bowen's
disease), basal-cell carcinoma, squamous cell carcinoma and scar.