Kids, while adorable, can be a real pain in the neck (at least for their parents).  Of course, occasionally, they will have pains in their own necks.  We have addressed several potential causes of the neck pain previously (ex, Torticollis, Strep Pharyngitis, Peritonsillar Abscess, Retropharyngeal Abscess, Lymphadenopathy, Lemierre’s Syndrome), but let us take a minute to review other causes of a Pediatric Neck Mass.

Neck Mass

• History and physical exam (along with a vigilant mind) are the primary tools required to evaluate and diagnose a pediatric neck mass! [Gov-Ari, 2014]

• Most often the mass is benign. [Shengwei, 2015]
• Most pediatric neck masses can be categorized as being:
  • Infectious / Inflammatory
    • Most common group!
    • Most apt to lead to emergent airway issue (ex, acutely expanding abscess)
    • May be superficial (ex, cat scratch disease) or deep (ex, retropharyngeal abscess)
  • Congenital
    • Rare, but not all neck masses are abscesses!
    • Often become apparent in late infancy.
    • Most common cystic neck masses (think way back to embryology class):

      • Thyroglossal Duct Cyst

        • Most common congenital neck cyst
        • Due to incomplete degradation of the thryoglossbal duct.
        • Often painless, rounded, neck mass.
        • Located within 2cm of midline.
        • Located anywhere between the base of tongue to the superior mediastinum.
        • Infrahyoid region is most common position.

      • Branchial Cleft Cyst

        • Remnant of one of the 6 branchial arches.
        • May form a cyst, a sinus, or a fistula.
        • Often present after upper respiratory tract infection.
        • Painful, enlarging mass or fluid draining area.
        • Cysts related to 2nd branchial arch are the most common.
        • Located – lateral to midline, anterior to sternocleidomastoid muscle, and posterior to the submandibular gland (ones derived from other arches have locations dependent upon the specific arch)

      • Lymphatic Malformation

        • Also referred to as lymphangiomas.
        • Located in the posterior and lateral neck regions.
        • May also be located on lower face.
        • Soft mass with red/blue discoloration.
        • Macrocystic lymphatic malformation = cystic hygroma
        • Microcystic lymphatic malformation may mimic solid masses.
    • All may become super-infected.
  • Neoplastic
    • Extremely rare (fortunately) – definitely more of an issue for adults
    • Often distinguished by being firm, fixed, and painless.
    • May have associated constitutional symptoms (fevers, night sweats, fatigue, and/or weight loss).
    • Lipomas – often in posterior triangle of neck, benign
    • Teratomas – typically large, heterogenous mass, in anterior or lateral neck
    • Malignancies –
      • Lymphoma, rhabdomyosarcoma, neuroblastoma and nasopharyngeal carcinoma
      • May have additional lymphadenopathy (always check for this)

Neck Mass Imaging

• Naturally, selecting imaging modality must take account for several considerations:
  • Pre-test probability of the condition
  • Risk of the condition (and potential associated complications)
  • Sensitivity and Specificity of the imaging modality
  • Risk of the imaging modality (ex, medical radiation)
• For Infectious Concerns:
  • If Deep Space infection is the concern, (ex, Retropharyngeal Abscess), CT is the best overall modality. [Ho, 2016; Lee, 2014]
    • Rapidly performed
    • Gives information about airway, blood vessels (and possible thrombosis, etc), and all deep space compartments.
    • Can differentiate retropharyngeal abscess from non-drainable edema.
      • Abscesses are typically rim-enhancing and have rounded contour. [Ho, 2016]
      • If rapidly developing, abscess may not have rim-enhancement.
  • For Superficial Structures, Ultrasound is a reasonable alternative. [Ho, 2016]
    • Can differentiate differentiate lymph node from other superficial structure.
    • For long-standing or complicated lymphadenitis, contrast enhanced CT may be beneficial to help evaluate possible vascular complications. [Ho, 2016]

• For Congenital Cystic Structures, Ultrasound is preferred initial modality. [Ho, 2016]
  • Can differentiate cystic, solid, and vascular structures.
  • Useful for differentiating lymph node from other superficial mass (ex, branchial cleft cyst).
  • For evaluation of congenital anomalies, U/S is helpful to determine the cystic characteristics, to describe the thyroid gland anatomy, and describe vascular structures. [Gov-Ari, 2014]
  • Interestingly, one study suggests that using CT to evaluate clinically apparent conditions, like thryoglossbal duct, can confound the diagnosis rather than clarify it. [Gov-Ari, 2014]
  • May require MRI, later, to help with surgical planning.

Moral of the Morsel

• Not every Neck Mass in a kid is either a lymph node or an abscess. There are other considerations.
• History and Physical exam are the most important tools to help make the diagnosis!
• Location matters! Midline or lateral? Anterior or posterior?
• U/S is a very useful (some would say the primary) imaging tool for most pediatric neck masses.
• If your clinical suspicion is high for deep space infection, skip the U/S and order the contrast enhanced CT scan.

References