Pediatric neck masses are a common reason for a child to visit a pediatrician’s office or emergency department. They are often categorized as congenital, inflammatory, traumatic, neoplastic or idiopathic. The vast majority of neck masses are inflammatory with up to 40% of infants and 55% of children having palpable benign cervical lymph nodes.
History As with the workup of any new patient, an accurate history can lead to a correct diagnosis most of the time. The age of onset of the mass, symptom duration, associated symptoms, and progression in size are all pertinent pieces of the history. Determining the age of onset helps delineate a congenital mass from an acquired mass. Associated symptoms such as pain would point to an inflammatory lesion. The presence of any degree of airway obstruction would warrant prompt treatment. A mass that progresses in size over the course of days is consistent with an inflammatory process, whereas rapid growth over weeks may be concerning for a malignancy. Recent travel is important to know especially in the case of scrofula (cervical tuberculosis). Environmental exposures to cats or contaminated water, for example, may lead to a diagnosis of cat-scratch disease or atypical mycobacterium, respectively. Finally, the presence of constitutional symptoms such as fever, weight loss, night sweats, or vomiting may favor a malignancy.
Physical Exam Critical elements of the physical exam include location in the neck, presence of skin changes, mobility of the mass, presence of tenderness, and size. Location is probably the most crucial part of the exam that can narrow down a diagnosis. Midline neck lesions in children are most commonly thyroglossal duct cysts, dermoid cysts, or benign lymph nodes. Antero-lateral masses may be consistent with branchial cleft cysts, lymphangiomas, or metastatic thyroid lymphadenopathy. Supraclavicular and posterior triangle masses may be worrisome for malignancy. Finally, lymphadenitis and lymphangiomas can cross all boundaries in the neck. Fluctuance or erythema of the skin is present mostly in inflammatory lesions and mobile lesions tend to be benign. Lesions less than one centimeter are consistent with benign lymph nodes and tenderness can denote an inflammatory process. Other head and neck findings are important to note as well. For example, tonsillar enlargement with exudates in the presence of cervical lymphadenopathy may be consistent with infectious mononucleosis.
Laboratory Tests While exhaustive laboratory testing is not recommended, certain tests can point to certain diagnoses. If an inflammatory/infectious process is suspected, CBC with differential and a CRP value can help determine the severity of inflammation. A PPD is often recommended as well to rule out tuberculosis or even atypical mycobacterium. Bartonella titers can be drawn from patient serum to diagnosis cat-scratch disease.
Imaging The three most common imaging modalities used in evaluation of head and neck masses are ultrasound, CT scan, and MRI. Neck ultrasound is a great initial screening tool because it is minimally invasive, lacks radiation exposure, does not require sedation, and is low in cost. Ultrasounds are able to distinguish cystic from solid lesions, approximate size of the lesion, and accurately evaluate the thyroid gland. In addition, it is a critical tool to assess the presence of normal thyroid tissue in its normal location during the workup of a thyroglossal duct cyst. Serial ultrasounds may also be used to follow the size of a benign appearing lymph node or nodes in neck if observation is the chosen treatment plan. Despite the many advantages of ultrasound imaging, there are several limitations. Accuracy of the exam is dependent upon the experience of the technician performing and interpreting the scan. Additionally, resolution and detail are inferior to CT or MRI and one is limited by the air-soft tissue interface and by bone. Nevertheless, ultrasound imaging tends to be underused as an initial imaging tool because of the availability of the CT scan. CT imaging can clearly delineate vital structures in the neck (neurovascular bundle) in relation to the lesion. A CT scan is the most common modality used to evaluate deep space neck infections and can be critical for surgical planning in any head and neck procedure. CT scan imaging is also most preferred when optimal bony resolution is required. However, radiation exposure is a concern with CT scan imaging so judicious use is important. MRI imaging is preferred for soft tissue lesions and neurovascular structures while delineating soft tissue planes where bone involvement is not a concern, such as in lymphangiomas or vascular malformations. MRI is no better than CT in detecting cellulitis or neck abscesses. In summary, ultrasound is a great initial screening that is often underutilized to evaluate cystic lesions, the thyroid gland, and lymphadenopathy. CT scan imaging is important for surgical planning, but premature use should be avoided due to cost and radiation exposure.
Fine Needle Aspiration and Biopsy Fine needle aspiration (FNA) can be used to potentially diagnose thyroid malignancies, lymphomas, or rhabdomyosarcomas with cervical involvement. However, this test is under utilized in children primarily due to non-compliance. Except in possibly the adolescent population, sedation would often be required to successfully complete FNAs in children. Additionally, the role of FNA in thyroid nodule evaluation in children is under investigation and may have a limited role since pediatric thyroid nodules have a higher incidence of malignancy compared to adults and would often require lobectomy or thyroidectomy. Finally, ultrasound-guide FNA can be therapeutic when used to aspirate deep neck abscesses or fluid collections.
Excisional open biopsy is indicated to rule out malignancy in cases of supraclavicular adenopathy, fixed lesions, rapidly growing masses in the absence of inflammation, or a persistent mass in the presence of constitutional symptoms.