We report a novel KRAS mutation in a patient with a large nevus sebaceous and an SLN who subsequently developed a vaginal botryoid rhabdomyosarcoma, an association not previously reported in the literature.
Our findings define a distinct clinical and molecular subgroup of SN, beside HRAS or KRAS-related SN, and expand the spectrum of mosaic skin conditions associated with receptor tyrosine kinase mutations.
Therefore, CUSP appears to be present, unmutated, and yet frequently undetectable by immunofluorescence in cutaneous lesions in both humans and mice that are associated with SHH pathway dysregulation (BCCs, BCNS, and nevus sebaceous).
Additional investigation by reverse transcription-polymerase chain reaction in four basal cell carcinomas and two nevus sebaceous tumors also showed the expression of Gli-1, another target gene in the patched-hedgehog signaling pathway, in all the basal cell carcinomas samples but not in any of the nevus sebaceous tumors examined.