• What features are present in this specimen?


Answer
The histology shows a lesion with: 
acanthosis (thickening of the epidermis)
horn cyst (presence of keratin within the cyst)
pseudohorn cyst (cyst containing keratin that 
communicate with the epidermis)
The base of the lesion is flat and shows no dermal 

invasion. It is level with the normal epidermis on the right.

a
• What is the diagnosis?
a
Answer
Seborrheic keratitis.

 
• What is the risk of malignant transformation?
a
Answer
Very rarely
 
• Is this condition related to sun-exposure?
a
Answer
No. The cause is unknown. They typically appear on the skin of people over the age of 40.
 
• What is Leser-Trelat's sign?
a
Answer
Sudden onset of  seborrheic keratosis related
to internal malignancy such as gastrointestinal adenocarcinoma.