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Cutaneous malignant neoplasms encompass a large spectrum of tumors that may arise from any of the component cells in skin or its underlying structures. This chapter separates pediatric tumors from those that predominantly affect adults; it further separates nonmelanoma skin cancer from melanoma.
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Many lesions are present at birth or shortly thereafter. Some have the potential for malignant transformation later in life; other lesions may be mistaken for a malignant growth.
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Dermoid cysts may be seen at birth as smooth, cystic tumors that may have both solid and cystic components. The cysts are usually attached to periosteum, are lined with keratinizing epidermis, and may contain hair and fat in addition to keratinous debris. Clinical examination most often shows tumors located in the lateral periocular or nasal areas. Because of tumor fixation to the underlying periosteum, the tumor may feel immobile when palpated. Treatment is simple excision, which may be delayed until later in childhood.
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Pilomatrixoma is usually a benign subcutaneous tumor that originates from the hair matrix and may show calcification. Clinical examination usually shows the tumors as stony-hard, slow-growing, deep subcutaneous masses that develop in early childhood. Rarely, invasive malignant variants with metastases have been reported. Treatment is simple excision.
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Sebaceous nevi are noted at birth as linear, raised, and tan- to yellow-colored patches on the scalp, face, or neck. The nevi may be several centimeters in size or much larger. Regression of the nevi is common until puberty, when growth of the nevi accelerates and lesions become multinodular and darker. Benign syringocystadenoma papilliferum, as well as various types of malignant neoplasms including basal cell carcinoma, squamous cell carcinoma, and adnexal tumors, may arise in adulthood. To provide optimum cosmesis and to minimize the risk of these malignant growths, patients should be treated in preadolescence with simple excision of the nevi.
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Neurofibroma may appear singly or may be multiple in von Recklinghausen disease or NF-1 (ie, neurofibromatosis with von Recklinghausen disease) and present as soft, skin-colored nodules composed of nerve cells, mast cells, and oval- to spindle-shaped nuclei in a wavy collagen matrix. The neurofibromatous nodules are usually unencapsulated and may infiltrate fat. Café au lait spots are associated with multiple neurofibromatous lesions and are usually excised for cosmetic or functional reasons. Neurofibrosarcoma may rarely develop in syndromic patients.
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Infantile Myofibromatosis
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In infantile myofibromatosis, single or multiple fibrous, firm nodules composed of fibroblasts and smooth muscle cells are present at birth or in early childhood. The nodules are palpable, firm, and either cutaneous or subcutaneous. Lytic lesions of the cranium may occur in as many as one-third of children, and visceral nodules are associated with the multicentric form. Visceral nodules may be confused with a malignant ...