Epidermal inclusion and dermoid cyst are slow-growing nonmalignant painless lesions Cysts or congenital lesions that are superinfected are often treated with incision and drainage followed by antibiotic therapy Complete excision may be performed when the acute infection has resolved Epidermal Inclusion Cyst Among the most common postpubescent skin lesions is the epidermal inclusion cyst (EIC) These have also been termed epithelial, sebaceous (incorrectly named), and pilar cysts EICs are acquired lesions and result from occlusion of pilosebaceous follicles, although some stem from inoculation of epidermal cells into the dermis via needlestick or other trauma A few may arise from epidermal cells that become trapped along embryonic lines of closure Lesions consist of firm, slow-growing round nodules that can range in size from a few millimeters to centimeters Most are solitary lesions found about the scalp and face, although they also may be located on the trunk, neck, and scrotum Histologically, these dermal and subcutaneous nodules consist of epidermally lined keratin-filled cysts Presentation is that of a slow-growing painless lump that may provoke concerns of malignancy A central punctum is frequently present, but not required for the diagnosis Diagnosis is made clinically At times, these cysts become acutely infected, and the patient complains of pain, erythema, and sudden increase in size Infected cysts should be incised and drained, as well as treated with oral antibiotics before elective excision Noninflamed cysts can be referred for elective excision that must include the entire sac to prevent recurrence In the rare case of children with multiple large EICs, Gardner syndrome should be suspected This autosomal dominant disorder is characterized by multiple EICs, intestinal polyposis, desmoid tumors, and osseous lesions Early diagnosis is especially important because of a 50% risk of malignant transformation of the intestinal polyps Referral to a gastroenterologist and geneticist should be considered in these patients Dermoid Cyst Dermoid cysts are congenital, subcutaneous nodules derived from ectoderm and mesoderm They occur with a male predominance Like EIC’s, dermoids are lined with epithelium However, they can be distinguished by their younger age distribution, location and histologically by the possible presence of hair, glands, teeth, bone, and neural tissue, as well as keratin The cysts usually present as solitary, round, firm nodules with a rubbery or doughy consistency on palpation, a smooth surface, and normal overlying skin Lesions are usually present at birth (but may not be appreciated until inflamed or infected) and tend to grow slowly Malignant transformation may occur but is rare Whereas some dermoids may be mobile, many are fixed to overlying skin or underlying periosteum Because these cysts form along areas of embryonic fusion, common sites include the nasal bridge, midline neck, or scalp; the lateral brow ( Fig 120.5 ); anterior margin of the sternocleidomastoid; and midline scrotum or sacrum An external ostium may or may not be visible A small percentage of patients with dermoid cysts may have other craniofacial abnormalities Occasionally, dermoids may have sinus tracts with deeper attachments extending intracranially or intraspinally Because the sinus tract can serve as a conduit for spread of secondary infection, midline lesions should have appropriate imaging (computed tomography [CT] and/or magnetic resonance imaging [MRI]) followed by elective excision Nasal Bridge Lesions Midline nasal masses in infants and children may be acquired (e.g., EIC) or congenital, the latter stemming from improper embryologic development (e.g., dermoid cyst, encephalocele, glioma) ED evaluation should focus on identifying lesions that require urgent subspecialist evaluation including encephalocele FIGURE 120.5 Dermoid cyst abscess (Reprinted with permission from Fleisher GR, Ludwig W, Baskin MN Atlas of Pediatric Emergency Medicine Philadelphia, PA: Lippincott Williams & Wilkins; 2004.) Dermoids are the most common embryologically derived midline nasal lesions (see previous discussion) Clinically, a firm, round, subcutaneous mass is seen in the midline over the dorsum of the nose Some have an overlying dimple, which may have an extruding hair ( Fig 120.6 ) Its attachment may extend only to the nasal septum or may go deeper through the cribriform plate into the calvarium Because of their proximity to the nasopharynx, these dermoids are particularly prone to secondary infection and fistula formation Hence, prompt excision by a specialist trained in their management is indicated after careful MRI or CT FIGURE 120.6 Preauricular surface pit (Courtesy of David Tunkel, eds MD In: Chung EK, Atkinson-McEvoy LR, Lai NL, et al., eds Visual Diagnosis and Treatment in Pediatrics 3rd ed Philadelphia, PA: Wolters Kluwer Health; 2014 With permission.) Gliomas are benign growths composed of ectopic neural tissue derived from embryonic glial tissue Lesions usually consist of a firm, gray, or red-gray nodule, ranging in size from to cm and can be mistaken for a hemangioma Most are extranasal (60%), occurring on the bridge of the nose The remainders are either solely intranasal masses (30%) or have both intranasal and extranasal elements (10%) By definition, they not have intracranial communication and have no neoplastic potential They are composed of neural and fibrous tissue, covered by nasal mucosa There is a male predominance To prevent possible distortion of ... cyst abscess (Reprinted with permission from Fleisher GR, Ludwig W, Baskin MN Atlas of Pediatric Emergency Medicine Philadelphia, PA: Lippincott Williams & Wilkins; 2004.) Dermoids are the most... eds MD In: Chung EK, Atkinson-McEvoy LR, Lai NL, et al., eds Visual Diagnosis and Treatment in Pediatrics 3rd ed Philadelphia, PA: Wolters Kluwer Health; 2014 With permission.) Gliomas are benign