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Salivary Gland Diseases in Children and Adolescents 259
Complications of parotidectomy occasional calcified foci at CT. The high-grade type is more solid and
An immediate complication of parotidectomy is bleeding. Delayed com- homogenous at both CT and MRI.
plications include haematoma, infection, transient facial nerve paralysis, The cut surface may contain cystic or solid areas, or both. Cystic
facial nerve paralysis, Frey’s syndrome, salivary fistula, and recurrence. areas contain viscous or mucoid materials. Microscopically, this
Warthin’s Tumour tumour contains two types of cells—mucous and epidermoid cells; the
The second most common benign salivary gland neoplasm in chil- proportion determines the grade of the tumour. The low-grade tumour
dren is Warthin’s tumour (papillary cystadenoma lymphomatosum, or is characterised by prominent cystic structures and mature cellular
adenolymphoma). This occurs mainly in the parotid gland. It is a slow- elements; the intermediate-grade tumour has fewer and smaller cystic
growing, painless swelling, usually unilateral with multiple masses in structures and occasional solid islands of epidermoid cells; and the
the gland. Developmentally, there is incorporation of the lymphatic high-grade tumour is a hypercellular solid tumour with cellular atypia
element, salivary gland tissue, and the paraparotid lymph nodes. and high mitotic figures.
CT and MRI demonstrate a well-circumscribed, homogenous cystic The treatment of mucoepidermoid carcinoma is surgery, depending
or solid lesion in the parotid gland. on the grade, location, and tumour extent. Wide local excision is adequate
Grossly, the tumour appears as multiple cysts of varying diameters for low-grade tumours. Block composite excision with radical neck
containing viscous fluid with solid areas of lymphoid follicles. dissection is appropriate for the intermediate- and high-grade varieties.
Microscopically, the tumour comprises tall eosinophilic columnar This may involve excision of the gland and facial nerve; petrosectomy;
cells with papillary projections into cystic spaces in a background of mastoidectomy; or resection of the ramus of the mandible, zygomatic
lymphoid stroma. arch, and the overlying skin, with subsequent nerve grafting and facial
Treatment is surgical excision (parotidectomy) of the tumour with reconstruction. In the palate, palatoalveolectomy, maxillectomy with
preservation of the facial nerve. or without radiotherapy, and chemotherapy are used postoperatively.
Radiation should be used with caution in children due to the long-term
Carcinomas effects. Tumour grading and subtype have a tremendous predictive
Acinic Cell Carcinoma effect on the prognosis.
Acinic cell carcinoma (also known as acinic cell adenocarcinoma or Rhabdomyosarcoma
acinous cell carcinoma) is a malignant epithelial neoplasm of salivary Rhabdomyosarcoma is the most common childhood soft tissue sar-
glands demonstrating serous acinar cell differentiation. It is second in coma, usually of the embryonic subtype. About 40% of all rhabdo-
occurrence to mucoepidermoid carcinoma in the paediatric population. myosarcomas arise in the head and neck region, and the parotid and
It is of varying malignancy, accounting for 6–37% of the total malig- the adjacent structures are usually involved by direct invasion. It is
nancies in children. It is more common in girls than boys, and 4% of common between 1 and 13 years of age, with most patients dying a few
the patients are younger than 20 years of age. months after initial diagnosis. Prognosis is usually poor because of late
The majority occur in the parotid gland. It typically presents as presentation (Figure 39.9).
a painless, slow-growing, enlarging solitary mass in the parotid, CT demonstrates heterogeneous attenuation of the tumour, and
occasionally multinodular and fixed to the skin and underlying tissues. MRI shows a poorly defined, heterogeneous mass. The treatment is
It is occasionally painful, with associated facial nerve paralysis. wide surgical excision of the tumour and adjacent structures with
The treatment modality is parotidectomy (superficial or deep) with reconstruction of the lost tissues. For advanced inoperable tumours, as
preservation of the facial nerve. Nodal and distance metastasis with is commonly seen in the African population, palliative chemotherapy
recurrence may occur. is recommended.
Mucoepidermoid Carcinoma Neurofibroma
Most studies agree that mucoepidermoid carcinoma (mixed epidermoid Neurofibroma is a benign nerve sheath tumour that may arise from the
and mucus-secreting carcinoma) is the most common salivary gland facial nerve within the parotid gland. It is rarely in the submandibular
malignancy in children. The majority are in the major salivary glands, gland. It may be solitary with gross facial disfigurement (Figure 39.10)
with about 45% in the parotid. The most frequent intraoral sites are the or have multiple lesions, as seen in von Recklinghausen’s disease.
palate and the buccal mucosa. It has a female predilection, and occurs Clinically, it feels like a bag of worms. CT demonstrates it as well-demar-
in the 5- to 15-year-old age group, peaking between 12 and 14 years cated, homogenous, and isoattenuated relative to muscle. It shows mod-
of age. erate enhancement following injection of contrast media. Occasionally, it
The clinical features depend on the grade of the tumour. They are may push the larynx or the trachea, causing respiratory difficulty (Figure
classified as low, intermediate, or high grade. In children, the majority 39.11). MRI may show low to intermediate signal intensity.
are of the low-grade variety with a very good prognosis. The low-grade Histologically, neurofibroma consists of loose collagen fibre with
presentation may simulate a benign tumour. Otherwise, it typically long, thin processes of nerve fibre and darkly stained elongated nuclei.
presents as a rapidly growing swelling with perineural and soft tissue The treatment is surgical excision. Recurrence occurs because of
invasion. High-grade tumours are usually found in children younger inadequate excision.
than 5 years of age.
Diagnosis is based on clinical, radiological, and pathological Evidence-Based Research
findings. The low-grade type shows smooth “benign appearing” Table 39.2 presents a study of surgical procedures on tumours of the
margins at US, CT, and MRI, containing cystic low attenuation and salivary glands in children and adolescents.