Head and Neck Masses Part 3
Part 3 review of head and neck masses including anatomy of the head and neck for radiology board review.
Also, as discussed in this episode, check out the rapidly growing community of residents, fellows, and radiology faculty recently started on Discord to help R3s and R4s get ready for radiology board exams during a time where people can't get together to study in person. Visit the link below for the group's missions/values and welcome page.
Show Notes/Study Guide:
What are some of the contents of the parotid space?
Parotid gland, portions of facial nerve (lateral to retromandibular vein), intraparotid lymph nodes.
What are some of the contents of the carotid space?
Carotid artery, jugular vein, cranial nerves 9-11, lymph nodes.
What are some of the contents of the masticator space?
Muscles: masticator, temporalis, medial and lateral pterygoids. Mandibular angle and ramus. Inferior alveolar nerve. Note that this space extends through the length of the temporalis muscle upwards through the lateral skull which is a potential avenue of spread of infection or malignancy.
What is the most common cause of a masticator space mass?
Abscess from odontogenic infection.
Infections in the masticator space may classically for board exam purposes spread to which other structures?
Cavernous sinus and/or orbital apex via the pterygopalatine fossa.
What types of sarcomas can classically involve the temporomandibular joint?
Rhabdomyosarcoma and chondrosarcoma may have a TMJ location.
What is the retropharyngeal space “danger space”?
Potential space seen at midline behind the alar fascia that extends all the way from the skull base to approximately T3 level.
What is the significance of the retropharyngeal/danger space?
Potential space that can facilitate spread of infection or malignancy from the neck into the mediastinum. A classic scenario is spread of tonsillar abscess/infection into the mediastinum.
What are differential considerations if you see necrotic lateral retropharyngeal lymph nodes?
Top considerations for necrotic lateral retropharyngeal nodes include squamous cell carcinoma metastases and papillary thyroid cancer nodal metastases. Enlarged lateral retropharyngeal nodes without necrosis raises the likelihood of lymphoma.
What is Grisel syndrome?
Grisel syndrome occurs when a retropharyngeal abscess causes torticollis and subluxation of the atlantoaxial joint, typically in children. If a question presents you with fever and new torticollis you need to think of this.
What is Lemierre syndrome?
Jugular vein thrombosis and septic emboli from a neck/upper respiratory tract infection. Recent ENT surgery would be common in a question stem. Classic association with fusobacterium necrophorum.
What are some of the contents of the parapharyngeal space?
Branches of the trigeminal nerve, pterygoid veins, and fat.
What is the significance on board exams of the parapharyngeal space?
Classic questions on board exams involve the significance of displacement of the parapharyngeal space because how the parapharyngeal space is displaced can guide to you the source of a mass/infection.
Describe the significance of parapharyngeal space displacement in terms of the surrounding anatomic compartments:
Medial displacement of parapharyngeal space: parotid space process
Anterior displacement: carotid space process
Posteromedial displacement: masticator space process
Lateral displacement: superficial mucosal space
(Another way of remembering this is that there are 4 spaces surrounding the parapharyngeal space. Masticator space is anterior, parotid space is lateral, carotid space is posterior, and superficial mucosal space is medial).
What anatomic structure separates level 1A from level 1B nodes?
Anterior belly of the digastric separates level 1A from level 1B nodes
What anatomic structure separates level 1B nodes from level 2A nodes?
Stylohyoid muscle
What anatomic structure separates level 2A from 2B nodes?
Internal jugular vein
What is the anatomic structure that constitutes the vertical border of Level 2 and Level 3 nodes?
Lower hyoid
What is the anatomic structure that constitutes the vertical border of level 3 and level 4 nodes?
Lower cricoid
Level 5 lymph nodes are defined as being posterior to what structure?
Sternocleidomastoid muscle
Which cancer is classic for a fossa of Rosenmuller mass in a young adult person of Asian descent?
Nasopharyngeal squamous cell carcinoma. Note that invasion of the parapharyngeal fat is a very bad prognostic sign. The most common location of nasopharyngeal squamous cell carcinoma is the fossa of Rosenmuller, and the earliest sign of this entity is often effacement of the fossa of Rosenmuller fat.
Where is the fossa of Rosenmuller?
Posterior and superior to the eustachian tube opening, posterior to the torus tubarius. Hence, nasopharyngeal squamous cell carcinoma can present with a unilateral mastoid effusion. You should particularly consider nasopharyngeal squamous cell carcinoma if you see a unilateral mastoid effusion with enlarged retropharyngeal nodes.
What are the three types of laryngeal squamous cell carcinoma by location? Which of these typically has the best prognosis?
Supraglottic, glottic and infraglottic. Glottic laryngeal squamous cell carcinoma typically has the best prognosis because it becomes symptomatic earlier (and therefore at lower stage) than the other subtypes and is also the most common of the subtypes. Subglottic is often clinically silent and presents with local adenopathy. Transglottic SCC means the tumor is aggressive.
What is the most accurate sign for cricoid invasion on imaging?
If you see tumor on both sides of the cricoid you can suspect cricoid invasion. Cricoid can have normal irregularity so that alone does not confirm invasion. Invasion of the cricoid is a key differentiator between whether the vocal cords may be spared at surgery—invasion means they typically cannot be spared.
