Introduction: Why imaging matters for neck masses in newborns

Finding a neck mass or neck lump in your infant or child can be alarming, but not all lumps are the same. Among them, a small proportion may be serious and interfere with vital functions such as breathing or feeding. One of the rare but significant cases is a cervical teratoma, a tumour composed of multiple tissue types, including cystic (fluid-filled), solid, fatty, and sometimes calcified structures.

These masses can resemble other neck masses; thus, medical imaging plays a vital role in reaching the correct diagnosis. This article will guide you through:

1. What do cervical teratomas typically look like on scans?
2. How do their features compare with other neck masses?
3. Why is early and accurate radiological identification important for safe treatment planning and newborn survival?

How do cervical teratomas look on images?

Cervical teratomas are usually heterogeneous masses. This means that instead of being uniform, they have a mixed appearance on scans, showing:

• Cystic spaces (fluid-filled cavities)
• Solid portions (tissue-like growth)
• Fat content, which appears as low-density areas on computed tomography (CT) images
• Calcifications, sometimes resembling bone or tooth-like structures

The combination of fat plus calcification in a single lesion is highly suggestive of a teratoma and is rarely seen in other congenital neck conditions.^1,2

Ultrasound findings in cervical teratomas

Ultrasound is often the first test used in both newborns and prenatal screening. On ultrasound, cervical teratomas usually appear as large, irregular, multiloculated masses. They often display both fluid-filled and solid parts, giving a mixed picture.³

While ultrasound is helpful to detect the presence and approximate size of the tumour, it has limitations. Fat and calcifications are not always clearly visible, and purely cystic teratomas may look similar to lymphangiomas (cystic hygromas). This is why ultrasound is useful for detection, but not always sufficient for a confident diagnosis.^3,4

CT scan features: spotting fat and calcification

CT scans are invaluable because they can demonstrate tissue densities in greater detail than ultrasounds. Cervical teratomas on CT usually appear as complex, heterogeneous masses that contain:

• Areas of fat density (lighter grey/black regions)
• Calcifications scattered within the tumour
• A mixture of cystic and solid tissue elements

This combination is unusual for other neck masses, which tend to be either purely cystic (such as branchial cysts) or purely solid (such as thyroid lesions). Thus, the presence of fat with calcification is one of the strongest radiological clues that a neck mass is a teratoma.^1,5

MRI findings: understanding tissue and airway involvement

Magnetic resonance imaging (MRI) is an excellent tool for assessing the full extent of the tumour and its impact on surrounding structures. Unlike CT, MRI does not involve ionising/ harmful radiation, making it safer for infants.

On MRI images, cervical teratomas typically show mixed signal intensities on both T1- and T2-weighted images, reflecting their diverse tissue content. MRI is particularly valuable for:

• Assessing airway compression, which can be life-threatening
• Understanding how close the mass is to vital structures, such as blood vessels and the trachea
• Guiding surgeons in planning safe removal^2,5

Why early and accurate diagnosis matters

Large cervical teratomas can cause complications even before birth. They may lead to polyhydramnios (excess fluid in the womb) and underdeveloped lungs because of pressure on the fetal airway.^4,6 Early diagnosis through prenatal ultrasound and MRI allows healthcare teams to plan specialised deliveries. In some cases, an EXIT procedure (ex utero intrapartum treatment) may be performed, where the baby’s airway is secured before the umbilical cord is cut. This highlights the life-saving role of imaging.⁵

How cervical teratomas compare with other common neck masses

FAQs

Can cervical teratomas be detected before birth?

Yes. Many are found on prenatal ultrasound, and MRI can provide additional information about size and airway involvement.^2,4

Are cervical teratomas usually cancerous?

Most are benign, but their location can make them dangerous because they may obstruct the airway.^3,6

Why do doctors use more than one imaging test?

Each scan offers different strengths: ultrasound for detection, CT for tissue details, and MRI for airway and surgical planning.^1,5

What treatment is needed after diagnosis?

Surgery is the main treatment, often soon after birth. Imaging ensures surgeons know exactly how the mass relates to critical structures before operating.²

Summary

• Cervical teratomas are rare, but can be life-threatening when compromising the airway
• Their hallmark radiological feature is a mixed appearance with fat and calcification, which distinguishes them from other congenital neck masses
• Ultrasound is helpful for detection, CT is best for identifying fat/calcification, and MRI provides crucial details for surgical planning
• Early diagnosis allows for better outcomes, especially when airway management is needed at birth