Case

This lesion was an incidental finding in hemorrhoids.  What was the likely gender of the patient?

Answer: Female

Comment: This is an example of hidradenoma papilliferum, a lesion that typically arises in the perinea area of woman.  It has estrogen receptors and is completely benign but can be mistaken for gynecologic adenocarcinomas. It is characterized by two cell layers, which can be seen in the high magnification images. This type of tumor also has characteristic mutations but of course it is not necessary to test for them.

Refs:

Liau JY, Lan J, Hong JB, et al. Frequent PIK3CA-activating mutations in hidradenoma papilliferums. Hum Pathol. 2016;55:57-62. doi:10.1016/j.humpath.2016.04.014

Pfarr N, Stenzinger A. Mutations of cancer-related genes in benign tumors: the example of hidradenoma papilliferum. Hum Pathol. 2017;62:246-247. doi:10.1016/j.humpath.2016.09.034