Abstract

Calcinosis cutis is benign entity, that is characterized by calcium deposition in subcutaneous tissues, with metastatic, dystrophic, calciphylactic, iatrogenic and idiopathic types. SCN is a variant of idiopathic calcinosis of unknown etiology that most commonly occurs in the head and neck of children and adolescents that presents as a single, small, painless and yellow-white nodule. Definitive diagnosis requires microscopic examination. Here, we present a case in association with NF1. A 13-year-old boy with NF1 diagnosed at 3 years of age developed a firm 0.3 cm white papule on the right lower eyelid. Concurrently, he developed left distal forearm neurofibroma. Microscopic examination of right arm mass showed malignant cells with up to 6 mitotic figures per high power field that was positive for SOX10 and S100 protein, and negative for desmin and myogenin indicating a malignant peripheral neural sheath tumor (MPNST). Microscopic examination of the eyelid lesion showed hyperkeratotic epidermis, papillomatosis, and elongated rete ridges, with a radial arrangement at the periphery of the lesion. Superficial dermis was studded with numerous amorphous accumulations dystrophic calcifications, sharply delineated at the base of the lesion. SCN can clinically mimic various entities such as verrucous papilloma, xanthoma, molluscum contagiosum and milia. Microscopic differential diagnosis are eruptive xanthoma, gout, and oxalosis. To our knowledge, no known association with systemic disease exists in the English literature. In this case, the patient was diagnosed with NF1 years before SCN and continuously developed neurofibromas, suggesting incidental diagnosis of SCN. Although, parathyroid gland hyperplasia and adenoma, bone lesions, and calcium metabolism disorders have been recognized in NF1. No electrolytes disorders, parathyroid hyperplasia or adenoma, or bone lesions were present. Nonetheless, this case is the first SCN in association with a syndromic disorder, NF1.

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