Related Experiment Video
Updated: Mar 7, 2026

Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model
Published on: September 7, 2013
Reasons for rarity of anal melanocytic naevi
Eman Aljufairi1, Fayek Alhilli2
1Department of Pathology, Salmaniya Medical Complex, Manama, Kingdom of Bahrain.
Abstract:
In the last 16 years only seven definite cases of anal melanocytic naevi have been reported in the literature. We describe three new cases, none of which were suspected clinically and were incidentally diagnosed on histological examination of haemorrhoidectomy specimens. The infrequency of these special site flexural melanocytic lesions may be related to changes in the involutionary mechanisms of the anal melanocyte proliferation. However, other factors related to the low detection rates by clinicians and pathologists need also to be considered.
Related Concept Videos
Skin Cancer
Basal Cell Carcinoma (BCC): BCC is the most common type of skin cancer, accounting for about 80% of cases. It typically develops in...
Pigmentation
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Changes in Skin Color: Clinical Perspectives
Albinism
Albinism is a genetic disorder that affects (completely or partially) the coloring of skin, hair, and eyes. The defect is primarily...
Epistasis
Assessment of the Rectum and Anus
Rectal Inspection
Begin by inspecting the perianal and anal areas for color, texture, rashes,...

