| There
is no universally accepted classification of hair follicle tumours.
[ Further reading:
Hair follicle tumors of the skin. A
review. Am J Pathol 1976;85:480-505.
Hair follicle tumors of skin. J
Cutan Pathol 1985;12:189-195.
A review and proposed new
classification of benign acquired neoplasms with hair follicle
differentiation. Am J Dermatopathology 1990;12:496-516. ]
It is often possible
to identify the predominant type of follicular differentiation: eg
outer root sheath, hair germ, infundibular etc. The tumours can be
classifed depending on which part of the hair follicle the lesion
differentiates toward or most closely resembles.
HAIR FOLLICLE
DIFFERENTIATION:
Hair follicle infundibulum-
Keratinous cystic structures
Outer root sheath- Clear
cells, peripheral palisading and hyaline basement membrane.
Follicular germ with mesenchyme-
Papillary mesenchymal bodies
Follicular bulb - Cells
of hair matrix included.
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