September 2019 HSC Section 1 Congenital and Pediatric Problems

Yuhan et al

Fig. 1. Structural landmarks of the oral cavity and oropharynx.

for a thorough examination (if feasible). Each of the oral cavity subsites can be directly viewed and palpated, taking note of whether these sites are soft or firm and irregular and whether the mucosa appears moist and of normal color. Additionally, mobile structures, including the oral tongue, can be assessed to see whether there is any diminished movement (ie, the tongue is fixed). A tongue blade applying downward pressure on the oral tongue and base of tongue is usually necessary to complete a more thorough oropharyngeal examination. Beyond an oral evaluation, any lesions in the oral cavity warrant a further compre- hensive head and neck examination. Certain oral lesions, such as ranulas, can have an intraoral (floor of mouth) component extending into the neck, whereas other le- sions, such as malignancies and infectious processes, can be associated with cervical lymphadenopathy. Thus, a neck examination, including palpation for lymph nodes, is essential, and further characterization of any palpated nodes based on mobility, soft- ness/firmness, and tenderness is significant. A cranial nerve examination, including evaluation for paresthesias, may provide clues to pathologies. Detailed information is provided in the sections describing specific diagnoses. Never- theless, several clinical principles should be followed to avoid missing a diagnosis while also minimizing unnecessary testing. Plain film radiographs have some utility for odontogenic lesions but have a limited role in the diagnosis of other oral cavity le- sions. CT, however, is useful in delineating bony involvement of lesions. When used for soft tissue lesions, CT should be performed with intravenous contrast; this modality is invaluable in most straightforward entities (ie, benign nondestructive lesions), such as a ranula or dermoid cyst. 5 On the other hand, MRI is helpful in further characterization of extensive or malignant soft tissue lesions, including sarcoma, and also possesses value in evaluating perineural involvement. 5 For smaller isolated lesions, tissue sampling may be valuable when a specific diag- nosis is not obvious. Smaller soft tissue lesions, removal of which would not cause DIAGNOSTIC CONSIDERATIONS

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