PMC4272958_01
Clinical features of nevus sebaceus. (A) Well-demarcated slippery, skin-colored, orange-peel like, linear plaque on the patient's left parietal scalp and face. (B) Round plaque on the patient's occipital scalp, showing alopecia. (C) A limbal dermoid with a skin-colored pedunculated papule on the left eyelid.
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F1
The patient had a slippery, skin-colored, hairless, orange-peel-like linear plaque on her left parietal scalp and face (Fig. 1A) and a round plaque on her occipital scalp (Fig. 1B). Facial examination revealed a limbal dermoid with a skin-colored pedunculated papule on the left eyelid (Fig. 1C).
Pathology of nevus sebaceus showing proliferative changes of sebaceous glands and apocrine glands in the epidermis (H&E, x100).
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F2
A biopsy specimen taken from the plaque showed hyperkeratosis, acanthosis, numerous sebaceous glands, and malformed hair follicles (Fig. 2), consistent with nevus sebaceus.
The KRAS mutation (c.35G>A; p.Gly12Asp) was identified in genomic DNA isolated from the nevus sebaceus lesion (arrows), but not from adjacent normal skin tissue or peripheral blood leukocytes.
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F3
Subsequently, we analyzed them for the second most common mutation in nevus sebaceus, KRAS c.35G>A (p.Gly12Asp), and detected this mutation in nevus sebaceus tissue from the patient, but not in her normal skin tissue or peripheral blood, confirming somatic mosaicism (Fig. 3).