Inverted follicular keratosis = التقران الجرابي المقلوب |
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INVERTED FOLLICULAR
KERATOSIS
Inverted follicular keratosis occurs most often in middle-aged and older men. Because of the wart-like morphology, it has been suggested that inverted follicular keratosis may represent a manifestation of human papillomavirus infection rather than a true follicular neoplasm. Inverted follicular keratosis presents as an asymptomatic, small (3 to 10 mm in diameter), solitary papule or nodule, most often on the face.Most lesions are located around the cheek and upper lip, but may occur on the eyelid. Histopathologic examination reveals an endophytic or exophytic-endophytic lesion consisting of several large epithelial lobules extending into the dermis. Four distinctive histopathologic patterns are recognized; namely, papillomatous, keratoacanthoma-like, solid, and cystic. The center of the epithelial lobules is composed of squamous cells focally arranged in a whorled pattern (squamous eddies). The periphery is sometimes occupied by basaloid cells. Additional features in some lesions include foci of trichilemmal differentiation, mucinous areas with spongiosis, and melanin pigmentation. A mild lymphohistiocytic inflammatory infiltrate often surrounds the lesion. Treatment is by surgical excision.
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