Clinical Features:

• Benign tumor occurring on the head and neck of adults
• Presents as a small skin-colored nodule with a central keratin plug and multiple vellus hairs

Histologic Features:

• Dilated primary hair follicle lined by infundibular or isthmic-type epithelium with an opening onto the epidermal surface
• Multiple smaller secondary hair follicles bud off the primary follicle, with the formation of germinative epithelium or mature hairs.
• The dermal collagen in and around the lesion is densely collagenized in parallel layers, with a sharp demarcation with the surrounding dermis.
• A variety of cell types are present within the hair follicle structures: isthmic, clear cells with nuclear palisading, basaloid matrical cells.
• Foci of sebaceous differentiation are sometimes seen.  When large sebaceous follicles connect to the central cavity of the primary follicle, the term sebaceous trichofolliculoma may be used.

Cases associated with this book:

Trichofolliculoma
Author: Artur Zembowicz M.D. Ph.D.

Conference: DermatopathologyConsultations.com Teaching Collection

Trichofolliculoma with sebaceous elements
Author: Artur Zembowicz M.D. Ph.D.