Abstract
Neurocristic hamartomas (NCH) of cutaneous origin are especially rare congenital or acquired tumors that often arise via aberrant embryologic development of pluripotent neural crest cells. Clinically, they most often present as pigmented macules or papules occurring on the scalp in association with alopecia. NCHs are characterized histopathologically by dermal melanocytic, fibroblastic, and neurosustentacular components and correct identification of this etiology is critical due to potential for malignant transformation, particularly in acquired NCHs. Our patient was a 6-year-old female with confirmed XPC mutation followed in our dermatology clinic since the age of 3. She had a history of multiple actinic keratoses but no prior skin cancers. A 4mm homogenous pink papule on the left frontal scalp concerning for basal cell carcinoma was noted during routine skin exam. After a three-month course of three times weekly topical imiquimod, the lesion had grown to a 6mm diameter. Patient was then referred to plastic surgery for definitive excision. Histologically, the lesion showed a well circumscribed proliferation of spindle cells with a trabecular and nested growth pattern. Perivascular psuedorosettes were identified as were areas that resembled well differentiated neural tissue. The spindle cells diffusely expressed S100 and SOX10, with patchy areas of MelanA and HMB45. CD34 diffusely highlighted the stroma. P16 was retained and PRAME was negative. To our knowledge, this is the first documented case in the literature of a cutaneous neurocristic hamartoma arising in a patient with xeroderma pigmentosum.
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