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 Dr Sampurna Roy MD

http://www.histopathology-india.net/dermpath.htm

Pilar sheath acanthoma is a rare, benign follicular hamartoma  described first in 1978 by Mehregan and Brownstein.

Clinical presentation: Clinically resembles a comedo and is characterized by a central pore- like opening plugged with keratin. Lesion is 5-10mm in diameter,

Site:  Solitary lesion occuring almost always on the upper lip. Cases have been reported on other areas of the head and face.

Microscopic features:  Central cystically dilated follicle containing keratinous material; follicle opening to surface;  buds of squamous epithelium radiate from the central pore; tumour lobules are composed of outer root sheath epithelium; abundant glycogen in some of the tumour cells ; epidermoid keratinisation ; lesion extends into the dermis or occasionally into the subcutaneous fat.
 
Differential diagnosis: -

1. Dilated pore (small finger-like projections extending into the dermis) ;

2.Trichofolliculoma (secondary hair follicles radiate from the wall of the primary follicle, an outer root sheath, inner root sheath and trichohyaline granules are noted in the secondary follicles) ; 

3. Poroma .
                       
      Image link(Dr Weems) ;   Case link

Abstract:

Pilar sheath acanthoma.Hautarzt. 1987;38(1):40-2.

Pilar sheath acanthoma--report of a case with review of the literature.Yonsei Med J. 1989 Dec;30(4):392-5.

Pilar sheath acanthoma - a benign follicular hamartoma. Dermatologica. 1983;167(6):335-8.

Pilar sheath acanthoma. A new benign follicular tumor.J Cutan Pathol. 1979 Oct;6(5):438-40.

Pilar Sheath Acanthoma. Arch Dermatol 1978 :114(10):1495-1497.

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