An inverted follicular keratosis (IFK) is a rare, benign neoplasm that typically presents as a single asymptomatic, exophytic, smooth or verrucous papule on the face or neck of a middle-aged or elderly man. It most commonly presents in the seventh decade of life, with a male to female ratio of 2:1. Lesions can be present for anywhere from 6 weeks to 3 years in most cases. An IFK, while benign, can mimic cutaneous malignancies clinically, necessitating further evaluation. Although the etiology is not completely understood, the most widely accepted theory is that an IFK arises from the follicular infundibulum. Others believe that it is a variant of an irritated seborrheic keratosis.
Codes
ICD10CM: L82.1 – Other seborrheic keratosis
SNOMEDCT: 394728005 – Inverted keratosis
Look For
Subscription Required
Diagnostic Pearls
Subscription Required
Differential Diagnosis & Pitfalls
To perform a comparison, select diagnoses from the classic differential