Keratoacanthoma in Xeroderma Pigmentosum: An Entity Beyond Guess

Radhika Varma

Abstract

Xeroderma pigmentosum is a progressive, degenerative genodermatosis. Clinical manifestations include sensitivity to ultraviolet radiation resulting in inflammation and neoplasia in sun-exposed areas of the skin, mucous membranes, ocular surfaces and occasionally neurologic degeneration.The basic defect lies in nucleotide excision repair, causing deficient repair of DNA damaged by UV radiation. XP patients have a greater than 1000-fold increase in the incidence of sunlightassociated skin cancer. Keratoacanthoma usually occurs on the sun-exposed areas in middle age and elderly individuals. It may be viewed as an aborted squamous cell carcinoma but rarely, may evolve into an overt malignancy. Case Report A 12 year old boy, clinically diagnosed as a case of XP was brought to our department with complaints of a slowly enlarging asymptomatic raised lesion on dorsum of nose since one month. He had an asymptomatic skin lesion over right leg below knee, which was excised and diagnosed as dermatofibroma by histopathology one year back. History of first degree consanguinity was present for his parents. No other family members had XP. On examination, freckled pigmentation was present over face, ears, chest and conjunctiva. He had a firm, hyperpigmented plaque of size 3 × 2 cm on dorsum of nose, the surface of which showed a central crater with erythema (Figure 1). The lesion had minimal crusting and peripheral scaling. His scholastic performance was poor compared to the peer group. Ophthalmology Keratoacanthoma in Xeroderma Pigmentosum: An Entity Beyond Guess Radhika Varma*, Priya Prathap Trivandrum Medical College Thrissur, Kerala, India Abstract Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder, characterized by photosensitivity, pigmentary changes, premature skin aging and increase in risk of developing malignant neoplasms of both skin and eyes. Keratoacanthoma (KA) is a rapidly growing benign skin tumor, occurring primarily in elderly light skinned individuals.