Reactive perforating collagenosis is a unique cutaneous disorder characterized clinically by recurrent, umbilicated, crusted papules arising in response to minor trauma. This disorder belongs to a group of dermatologic conditions that have been classified as "transepidermal elimination" syndrome.

We report a patient with acquired reactive perforating collagenosis without any associated disease and family history.

Xeroderma pigmentosum is a rare autosomal recessive disorder characterized by extreme photosensitivity and defect in repair of damage to DNA Lentigenes, freckles, telangiectasia and the hyperpigmented cutaneous macules in the sun-exposed area and early development of cutaneous malignancies are observed. In addition to cutaneous symptoms, ophthalmologic changes and neurologic abnormalities can be associated.

We report a case of xeroderma pigmentosum associated with squamous cell carcinoma in a 4-year-old girl. This case is thought to be more earlier development of malignancies than ever reported.