Related Experiment Video
Updated: Aug 10, 2026
Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model
Published on: September 7, 2013
Malignant melanoma in xeroderma pigmentosum: search for a precursor lesion
J B Stern1, G L Peck, H M Haupt
1Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD.
Background:
Malignant melanomas occur with increased frequency and at an early age in patients with xeroderma pigmentosum (XP).
Objective:
The purpose of this study was to describe the histologic features of malignant melanomas in patients with XP and to search for a possible precursor lesion.
Methods:
Clinical records and hematoxylin-eosin-stained sections of 19 malignant melanomas from seven patients with XP were examined. A search was conducted for malignant melanoma precursor lesions (melanocytic nevi and solar lentigines lateral to and contiguous with the malignant melanomas). Basal cell carcinomas removed from the same patients were used as controls.
Results:
Malignant melanomas were characteristically found in biopsy specimens of small elevations and/or changed color foci arising in large, flat, darkly pigmented, gradually enlarging macules. Histologically, solar lentigo was lateral to and contiguous with malignant melanoma in 88% of the malignant melanomas. Transitional areas were present. A significantly lower number (22%) of contiguous solar lentigines, without transitional areas, were observed in the basal cell carcinoma controls. Most of the invasive malignant melanomas were spindle cell malignant melanomas.
Conclusion:
We propose that solar lentigo is the most common precursor lesion of malignant melanoma in patients with XP.
Related Concept Videos
02:23Abnormal Proliferation
01:38Nucleotide Excision Repair
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
01:19Pigmentation
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...
01:30Skin Cancer
Basal Cell Carcinoma (BCC): BCC is the most common type of skin cancer, accounting for about 80% of cases. It typically develops in...