Lumps arising in the head and neck constitute an important diagnostic category in children. As malignancy in this age group is relatively rare, lumps that are not due to inflammatory or infectious causes often prove to be cysts. Because of the varied types and locations of these cysts, patients may present to a wide variety of practitioners, including primary care physicians, pediatric surgeons, otolaryngologists, plastic surgeons, ophthalmologists, and neurosurgeons, all of whom need to be aware of the diagnostic techniques and treatment options.
The purpose of this study was to review the characteristics of the most common cysts appearing in the head region in pediatric patients. Ninety cases of cysts presenting in the head of children treated with surgical excision during 12-year period were subjected to retrospective analysis. A review of the clinical and pathological diagnoses in these cases revealed that 95% of the cysts fell into one of the 4 following categories: dermoid cyst, pilomatrixoma, epidermal cyst, and preauricular branchial remnants.
A Dermoid cyst is a benign unusual neoplasm that is derived from both the ectoderm and the mesoderm (Fig 1). A keratinizing squamous epithelium is typically present together with dermal derivatives such as hair follicles, smooth muscle, sweat and sebaceous glands, and fibroadipose tissue. Although these neoplasms may be seen at birth, the age at presentation can vary widely, and sudden changes in size can make diagnosis more difficult. Approximately 7% of all dermoid cysts occur in the head, with the most commonly reported locations being periorbital, nasal, submental, and along the cranial sutures.[1–6,7] Histologically, a dermoid cyst must contain 2 germ cell layers, and a pathologic confirmation is required to establish the diagnosis. Dermoid cysts are excised to establish a pathologic diagnosis, prevent subsequent infection, and ameliorate a cosmetically deforming lesion. Imaging studies are indicated when intracranial or intraorbital extensions are suspected.
Pilomatrixoma, also known as calcifying epithelioma of Malherbe, is a benign skin neoplasm that arises from hair follicle matrix cells (Fig 2). Clinically, it presents as a superficial hard mass with bluish discoloration of the overlying skin, which may become attenuated or ulcerated. Pilomatrixomas occur on the head, neck, and upper extremities and less frequently on the trunk and lower extremities. Surgical removal is generally curative, recurrence after complete excision is rare, and malignancy has rarely been reported. Pilomatrixomas are common and account for 1 of every 500 specimens submitted by surgeons. Despite their frequent occurrence, pilomatrixomas are often confused with other skin conditions. Pilomatrixomas can be distinguished from epidermoid and dermoid cysts by the presence of irregular nodules, which slide freely under the overlying skin. The overlying skin might have a red or blue hue.
Epidermoid cysts are firm, round, and mobile with normal overlying skin. In addition, epidermoid cysts often present among older patients (adolescents and adults).
Histologically, pilomatrixomas are sharply demarcated and contain basaltic cells and eosinophilic keratinized (shadow) cells. The proportions of these cellular components vary but the basaloid cells generally constitute the smaller component; in some cases, no basophilic cells are noted. These basaloid cells are fairly uniform in size, with round nuclei, small nucleoli, and delicate nuclear membranes. The shadow cells have distinctive cell borders and contain central unstained areas corresponding to the lost nuclei that are characteristic of pilomatrixomas. Mineralization in keratinized cells is a common feature. Another common finding for pilomatrixomas is granulomatous inflammation in areas of keratinization.
Branchial derivatives may take the form of cysts, sinuses, or cartilaginous remnants, and it is possible to identify the relevant branchial arch from the anatomic position. Strangely, although most remnants have usually been present since birth, branchial cysts most commonly present in adolescence or adulthood.
Preauricular and First Branchial Remnants
Small sinuses and cartilage remnants just in front of the ear are the commonest finding. Such preauricular pits may be blind but occasionally lead to a racemose collection of small cysts or to the cartilage of the helixn (Fig 3); otherwise, inconspicuous pits may present as an infection or an abscess in front of the ear. A true sinus or fistula from the first branchial arch is rare and has an opening just below the angle of the jaw along the uppermost border of the sternocleidomastoid. A communication with the external meatus may be identified during dissection.
The most common location for dermoid cysts was periorbital (92%), followed by the nasal bridge (4.76%) and the midforehead (4.76%). In this series, none of the dermoid cysts had intracranial or intraorbital extension.
The most common location of pilomatrixomas in the head was the cheek (45.5%) and the eyebrows (45.5%).
Eighty of branchial remnant cysts were located in the preauricular area.
All children with dermoid cysts presented with a palpable mass. Other presentations included a change in the size of the mass, a fixed position, firm consistency, or cystic consistency. Only 1 patient (1.8%) had a history of local infection.
The most common presentation of pilomatrixomas was a hard, subcutaneous, slowly growing mass. No patients had a history of local infection.
The typical presentation of preauricular branchial cysts was a slowly growing mass in front of the tragus.
In this series, only one patient complained of pain in the area of the cyst.
Fourteen patients had preoperative imaging: CT in 12 patients and US in 3 patients (1 patient had both CT and U/S).
Treatment of all cysts was direct excision. For the preauricular branchial cysts, a window of helical cartilage was excised together and in continuity with the mass. The operative wounds were carefully closed in layers.
ePlasty. 2010;10:e37 © 2010 Open Science Company
Cite this: Occurrence and Characteristics of Head Cysts in Children - Medscape - May 27, 2010.