Purpose or Case Report: Identify the most common diagnoses of superficial head and neck lesions in children under 4 years of age, and correlate imaging and pathologic findings.
Methods & Materials: A HIPPA compliant, IRB approved, 5-year retrospective review was performed at a tertiary care pediatric hospital. Patients up to 4 years of age, with head and neck sonogram (US), and imaging indication that included “lump”, “bump”, or “mass” were included, with or without imaging follow up with US, radiography (XR), computed tomography (CT), or magnetic resonance (MR) within next 180 days. EMR, radiology reports, and pathology reports were reviewed. Patients with no palpable lump, known malignancy, lost to follow-up, or unavailable imaging information were excluded.

Imaging diagnoses were categorized as; N: negative, AS: anatomic structure, C: cystic, S: solid, O: other. Pathology reports were classified as; I: inflammatory/infectious, neoplasm (BN: benign, MN: malignant), CL: congenital, NOS: nonspecific. Percentage of most common imaging and pathologic diagnoses were calculated and tabulated. A Radiologic-pathologic correlation for the most common benign and malignant lesions was performed.
Results: A total of 915 patients of 0-4 years (mean: 1.4y; 50% M, 50% F), with head and neck US, from 5/2014 to 5/2019 were evaluated. 75.7% (693) had a single US, and 24.2% (222) had follow up imaging within 6 months (US:126, XR:7, CT:41, MR:47, PET/CT:1). Lesion diagnosis was 77% (710) by imaging (91% US, 4.3% US/MR, 3% US/CT, 0.7% US/XR) of likely benign lesions (S: 44%, C: 27% AS: 14%, O: 2.5%. N: 10%). 22% (205) of lesions had pathologic confirmation, BN: 51% ([105] C: 82%, S: 16%, O: 2%), CL: 27% ([56] C: 84%, S: 7%, O: 4%, N: 6%), I: 18% ([38] S:55%, C: 42%, O: 3%), MN: 2.4% ([5] S:100%), NOS: 0.5% ([1] C: 100%).

Of 693 patients with single US, 18% (128) were excised and benign. Of 222 lesions with additional imaging, 34% (77) were excised. Only 1 malignant and 15 benign lesions had incorrect imaging diagnosis. Common imaging diagnoses were solid (lymph nodes, infantile hemangioma, fibromatosis colli). Common pathologies were cystic and solid (dermoid cyst, thyroglossal duct cyst, lymphadenitis). Malignant lesions were uncommon, >3cm, solid, and heterogeneous.
Conclusions: Ultrasonography is highly accurate for evaluation of head and neck lesions in infants and young children. Benign lesions are common, cystic and solid. Malignant lesions are uncommon, larger, solid, heterogeneous, and require further imaging evaluation.