Cornoid Lamella is indicative of DSAP

Here I found (on another website) some information that relates to diagnosing DSAP (a form of porokeratosis). I am uncertain if this lab test differentiates DSAP from Actinic Keratosis. I assume that it does. Any help on this topic would be helpful. 

Histologic Findings: The cornoid lamella is the histopathologic hallmark of all forms of porokeratosis. It is essential that the specimen be taken from the peripheral, raised, hyperkeratotic ridge to demonstrate this finding. The cornoid lamella consists of a thin column of tightly packed parakeratotic cells within a keratin-filled epidermal invagination. The parakeratotic column extends at an angle away from the center of the lesion and develops from interfollicular epidermis but may involve the ostia of hair follicles or sweat ducts. Within the parakeratotic column the horny cells appear homogeneous and possess deeply basophilic pyknotic nuclei. In the epidermis beneath the parakeratotic column the keratinocytes are irregularly arranged and have pyknotic nuclei with perinuclear edema. No granular layer is seen within the parakeratotic column, while the keratin-filled invagination of the epidermis has a well-developed granular layer. The papillary dermis beneath the cornoid lamella contains a moderately dense lymphocytic
infiltrate and dilated capillaries.  

Note that DSAP can and may be diagnosed without doing this lab test. A good doctor will be able to positively identify DSAP visually.

LINKS

The 5 layers of the epidermis - Skin basics.