of the follicular infundibulum (TFI) is a simple follicular
acanthoma with characteristic histopathologic features.
(1) solitary tumours,
(2) eruptive tumours,
(3) TFI - associated with
other lesions of Cowden's disease,
(4) TFI- associated with a single
tumour such as nevus sebaceus, and
(5) TFI-like epidermal changes.
Clinically presents as
a small asymptomatic, smooth or slightly keratotic papule or plaque.
Sites: Head and
neck or upper chest.
Symmetrical tumour with plate-like growth
pattern of the squamous cell (similar to isthmic or outer root
sheath epithelium) parallel to the surface epithelium ;
attachments to the epidermis ;
Basal cell palisade ;
epithelium eosinophilic and pale staining than the overlying epidermis ;
Small ducts and microcavities with keratin in the lesion; PAS- positive
Inverted follicular keratoses ;
Plaque-like seborrheic keratosis
Superficial basal cell carcinoma;
tumors of the head and neck.