inverted follicular keratosis

Definition : Benign tumor of the follicular infundibulum.

Images

 Inverted follicular keratosis

• https://twitter.com/STEVENKOLKERMD/status/1575029425590050816
• https://twitter.com/sortizreina/status/1117868031584026624
• https://twitter.com/ArjunRamaiya1/status/1479920346862174214

Synopsis

 Patterns :

• verrucous pattern : wart-like variant
• crateriform pattern , crateriform pattern : keratoacanthoma-like pattern
• solid nodular pattern / compact pattern

 well-circumscribed endophytic growth of squamous cells with lobular extension into the dermis
 exophytic lesions with a keratoacanthoma-like appearance
 variable number of squamous eddies
 may be increased secondary to irritation
 possible peripheral basaloid cells with occasional mitotic activfty

Digital cases

 JRC:10550 : Inverted follicular keratosis.
 JRC:10551 : Inverted follicular keratosis.
 JRC:10552 : Inverted follicular keratosis.

Differential diagnosis

 irritated seborrheic keratosis
 squamous cell carcinoma
 tricholemmoma
 verruca vulgaris

See also

  cutaneous anomalies

• solitary cutaneous nodule

 keratoses / keratotic anomalies