Case Number : Case 4109 - 20 Oct 2022 Posted By: Saleem Taibjee

Looks concerning for SCC

I think this is a Onychopapilloma (OP) associated with subepidermal onycholemmal cysts. The calcifications can be seen in these cysts and they are not uncommon in OP

Not so many responses this time, perhaps reflecting how we all struggle with nail specimens.

So well done to Igor....

I was very grateful to Prof Eckhart Haneke for his expert opinion on this case, as follows:

"In my special onychopathology practice, this is not so uncommon. I have no doubt that it is an onychopapilloma with some secondary infection explaining the neutrophils in the distal keratotic tip of the lesion. The epithelial buds and cyst formation with a tendency to calcification are very characteristic. Some nuclear atypia is normal for onychopapillomas, particularly binucleate cells and an occasional apoptotic cell.

This is essentially a benign lesion. I would treat it as such. However, as two consulting histopathologists are not sure about the benignity I would recommend to just follow the patient once yearly. Recurrences are relatively common and not necessarily a sign of a malignant lesion."

McKee’s textbook also states: Pathology indicates papillomatous acanthosis of the distal matrix spreading to the nail bed, longitudinal canaliform dystrophy of the ventral nail plate, matrix-like metaplasia of the nail bed and distal subungual hyperkeratosis.

BW
Saleem

Sorry, I'm late. Very interesting case, especially for a general pathologist like me. I'm learning, in this case, beacause my thought was an early SCC. Thanks, Saleem.