Angiosarcoma of the Auricle in a Patient with Xeroderma Pigmentosum Variant

Xeroderma pigmentosum (XP) is an inherited autosomal recessive disorder characterized by photosensitivity and an increased risk of developing multiple skin neoplasms at sites exposed to the sun. We report a 73-year-old Japanese man with angiosarcoma of the auricle and an XP-variant, which is a very rare condition. In this case, long-term physical stimulation due to auricular deformation after surgery may have been the cause. Angiosarcoma associated with XP has a better prognosis than common angiosarcoma, perhaps because of the smaller tumor size. As XP patients are at high risk of skin neoplasms, they consult dermatologists regularly, and therefore skin tumors are likely to be detected early.

Novel variants in POLH and TREM2 genes associated with a complex phenotype of xeroderma pigmentosum variant type and early-onset dementia

BACKGROUND

Xeroderma pigmentosum (XP) is a rare, genetically heterogeneous, autosomal recessive disorder caused by defects in the genes involved in repairing DNA damaged by ultraviolet radiation. These defects lead to a propensity to develop skin cancer at early ages as a hallmark, and progressive neurological degeneration can be observed in around 25% of patients. Eight clinically heterogeneous groups have been identified so far (XPA to XPG and XPV). Xeroderma pigmentosum variant type (XPV) is associated with pathogenic variants in POLH on chromosome 6, and no neurological dysfunction has been seen in these cases. However, on the same chromosome, it has been shown that TREM2 is associated with some types of dementia, particularly in patients with a behavioral variant frontotemporal phenotype.

METHODS

Gene mutational analysis was performed by whole-exome sequencing.

RESULTS

We report a case of a Caucasian woman with XP that developed behavioral and cognitive impairment at age 37. Whole-exome sequencing identified novel homozygous variants in POLH c.638C>G (p.Ser213*) and TREM2 c.154C>T (p.Arg52Cys), classifying the patient as XPV and suggesting that her frontotemporal dementia phenotype could be related to the variant in TREM2.

CONCLUSION

This paper describes a rare case of a patient with two novel variants in the same chromosome associated with XPV and early-onset dementia.