Case Number : Case 1620 - 9 September Posted By: Guest

The full-thickness p53-positivity with a ki67 increased expression, also in upper epidermis, fit well with a mild keratinocytic atypia and diskeratosis morphologically observed. The acrothrychium and acrosyringyum are spared with an abrupt border, and the basal layer is hyperpigmented,without significative increased number of melanocytes. These findings seem consistent with "bowenoid actinic keratosis", pigmented variant.

Hmm!   Seems this case was a little spoilt.  I was hoping you would have had a chance to give opinions on the H&E's without the IHC.  You should note the lack of maturation of the cells (even at low power the epithelium looks a little to mauve due to high nuclear cytoplasmic ratio). A higher magnification one can appreciate the subtle lack of maturation, occasional prematurely keratinising cells and no doubt you will find mitoses at all levels if you search carefully. The sudden and very abruptly orthokeratinisation near the surface without parakeratosis evident might fool you into no considering actinic keratosis here.  So please be aware of this particularly subtle type of bowenoid dysplasia.  It is morphologically similar to cases that can be seen in genital sites and also very easily missed. 

My diagnosis: Pigmented atrophic pattern of subtle bowenoid actinic keratosis!