Xeroderma pigmentosum and its relation to ophthalmic neoplasm.
Xeroderma pigmentosum (XP) is a rare genetic disorder characterized by sever hypersensitivity to ultraviolet (UV) light due to mutations in genes responsible for DNA repair, that are involved in nucleotide excision repair (NER). XP is caused by autosomal recessive mutations. In XP repair of UV-associated damage is impaired, UV leads to dipyrimidine nucleotide products, which are recognized by the NER pathways. Unrepaired products in XP during replication lead to errors resulting in the incorporation of a wrong nucleotide, resulting in characteristic C-to-T or CC-toTT mutations of UV damage[1,4]. Alterations in eight different genes have been associated with XP; XPA, XPC, and XPD are the most common. XP disorder lead to complete protein loss, and that the mutations may occur in many sites of different genes, so the immunohistochemistry represents an attractive technique to identify the possible aberrant gene in tissues from the patient. Overall the clinical manifestations of XP are commonly seen in sun-exposed areas such as skin, mucous membranes, and eyes, including the ones seen after a few minutes after a sun exposure (blisters), pigmented freckles, ocular abnormalities, and well known significant increased risk of developing neoplasia in these areas. Ocular manifestations in patients with XP include photophopia, conjunctivitis, ectropion, and neoplasia. The spectrum of neoplasia affecting the ocular surface of patients with XP has not been studied as cutaneous manifestations, but includes squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and malignant melanoma (MM).
Xeroderma pigmentosum is a rare, autosomal recessive disease caused by defect in DNA repair. Patients with xeroderma pigmentosum often have cutaneous and ocular sun sensitivity, pigmented freckles, multiple skin and eye cancers. XP predominatly affects the UV exposed ocular surface, resulting in eyelid atrophy, corneal dryness, and conjunctival tumors. In this study, we experienced the tumors involving the ocular surface from XP patient. Histo-pathological evaluation and immunohistochemistry was preformed using antibodies against the most common mutated genes in XP (XPA, XPC, and XPD). Sudanese male presented with neoplasms involving the ocular surface: squamous cell carcinoma(SCC), conjunctival abnormalities, including recurrent melanoma and nodular basal cell carcinoma(BCC) of the eyelid.