Scalp and calvarial masses - Pediatric Surgery

Scalp and calvarial masses - Pediatric Surgery Scalp and calvarial masses . Epidermoid and dermoid cysts . click the images for more details     Incidence. Tumor-like masses and tumors of the scalp and the calvaria occur frequently. Epidermoid and dermoid cysts belong to the most often observed masses in this region.  Clinical significance. 1. Deformity. 2. Infection. 3. Increase in size. 4. Intracranial extension (in some frontal and occipital dermoid cysts) and subsequent meningitis and abscess. 5. Carcinophobia of the parents.   Etiology.  Epidermoid and dermoid cysts are of developmental origin and derivations of the subsequent dermis.   Pathology, anatomical types .Illustration The cysts which lie under the skin and / or in the skull and rarely out- or inside the dura (categories 1 to 5). They have some favorite sites: lateral and less frequently medial periorbital and frontoparietal position as well as over the anterior fontanel. Frontonasal types lie between the nasion and the tip of the nose, occipital types beyond the posterior fontanel at the back of the head. show details Clinical presentation (history, findings, clinical skills) . Illustrations Dermoid cysts are observed by the parents, occasionally felt during hairdressing. The lateral periorbital epidermoid cyst characteristically lifts the lateral end of the brow as a firm mass fixed to the periosteum. As a rule, the skin over the cyst is adherent to it and may exhibit a fine opening without or with protruding hair. The findings are similar for the other locations. The fronto-parietal types with intraosseous site (category 3a) are mainly found by chance on a lateral skull x-ray performed for other reasons; the rounded or oval-shaped bony defects exhibit sharp edges with a sclerotic border. Frontonasal types lie between the nasion and the tip of the nose and occasionally at the anterior end of the nasal septum; occipital types lie over the closed posterior fontanel or beyond it. show details Natural history .   Epidermoid and dermoid cysts are masses which grow by the accumulation of dermal debris, slowly increasing in size. Malignant degeneration is unusual although spontaneous perforation may occur, which renders total excision difficult.  Differential diagnosis.Illustrations In general, all existing scalp and calvarial masses of childhood have to be considered. The specific differential diagnosis depends on the site of the mass; for instance, lateral or medial position: In the typical lateral periorbital or in the fronto-parietal intraosseous position with the described radiological characteristics, the diagnosis of an epidermal cyst is very likely. In the medial periorbital location, a mucocele caused by an obstruction of the lacrimal duct, or a dacryocystitis may be considered; in a frontonasal position, a nasal glioma or a nasal encephalocele.show details Work-up examinations.Illustration In case of a visible lateral dermoid cyst a lateral x-ray of the skull may be sufficient. In case of a mass over the midline, depending on the age, an ultrasound and/or a CT/MRI (with or without reconstruction) is necessary to exclude an intracranial extension, and if present, to identify its site. Additional examinations are also indicated if it seems unlikely that the underlying cause of the mass is a dermoid cyst; they depend on the diagnostic and therapeutic needs of the pathologies most likely to be expected. show details Therapy.  Except for periorbital lateral epidermoid cysts, surgery should not be performed under out-patient conditions. To avoid recurrences and infections, a total resection is necessary, and in case of intracranial extension, the revision should be performed by a pediatric neurosurgeon. In every case a histological work-up is indicated for the final diagnosis.   Prognosis.  Permanent cure on total excision.