Article Contributors: 
    Sean Klepper M.D.
    Artur Zembowicz M.D....

    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.

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    Cases associated with this book:

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

    Conference: Teaching Collection
  • Trichofolliculoma with sebaceous elements
    Author: Artur Zembowicz M.D. Ph.D.