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Neuroanatomie (Subject) / Alles (Lesson)

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• Sphenoid sinusitis is of great clinical concern as it may Extend intracranially due to presence of valveless veins.
• Sinus mucous retention cyst versus mucocele Mucous retention cyst_ Obstructed mucous glands within mucosal lining. Usually round. 1 to several cm in diameter. Mucocele_ Entire sinus is obstructed. Expansion of sinus. Sinus wall bony thinning and remodeling. Mass may be present obstrucing draining ostium.
• Inverting Papilloma Neoplastic epithelium inverts and grows into underlying mucosa of lateral nasal wall. Surgically resected due to association with squamous cell carcinoma.
• Juvenile nasopharyngeal angiofibromas Male adolescents with epistaxis. Benign tumor but can be locally aggressive. Fills nasopharynx and bows posterior wall of maxillary sinus forward. Retromaxillary pterygopalatine fossa location is a hallmark feature. Avidly enhance.
• Malignancies of paranasal sinuses and nasal cavity. Squamous cell carcinoma. Lymphoma. Minor salivary tumors.
• Most common salivary malignancies include Adenoid cystic carcinoma. Adenocarcinoma. Mucoepidermoid carcinoma.
• Esthesioneuroblastoma Arises from neurosensory receptor cells of olfactory nerve and mucosa. Occurs anywhere from cribriform plate to turbinates. Often quite destructive by time of diagnosis. Usually found high within nasal vault.
• Three most common primary (mets by far more common) skull base malignant tumors Chordoma (destructive midline mass). Chondrosarcoma. Osteogenic sarcoma (from radiation or Pagets degeneration).
• Cholesteatoma Soft tissue mass (epidermoid cyst of desquamating stratified squamous epithelium) within middle ear cavity. Typically associated with bone erosion. Superior tympanic membrane (pars flaccida) is the most common site. CT images extent of disease.
• Opacified petrous apex differential Retained fluid secretions_ Dark T1, bright T2, no enhancement. Petrous apicitis_ Dark T1, bright T2, and ring enhancement. Nonaerated petrous apex_ Bone marrow, bright T1, dark T2, and no enhancement. Cholesterol granuloma_ Hemorrhagic component, bright T1 and T2.
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• Cholesterol granuloma Granulation tissue within partially obsructed petrous air cells. Have cholesterol and hemorrhagic component (high T1 and T2 signal).
• Deep anatomy of the head and neck is subdivided by layers of deep cervical fascia into the following spaces_ (1) Superficial mucosal. (2) Parapharyngeal. (3) Carotid. (4) Parotid. (5) Masticator. (6) Retropharyngeal. (7) Prevertebral.
• Mucosal head and neck compartment contents Squamous mucosa. Lymphoid tissue (adenoids, lingual tonsils). Minor salivary glands.
• Mucosal head and neck compartment pathology Nasopharyngeal carcinoma. Squamous cell carcinoma. Lymphoma. Minor salivary gland tumors. Juvenile angiofibroma. Rhabdomyosarcoma.
• Parapharyngeal head and neck compartment contents Fat. Trigeminal nerve (V3). Internal maxillary artery. Ascending pharyngeal artery.
• Parapharyngeal head and neck compartment pathology Minor salivary gland tumor. Lipoma. Cellulitis/abscess. Schwannoma.
• Parotid head and neck compartment contents Parotid gland. Intraparotid lymph nodes. Facial nerve (VII). External carotid artery. Retromandibular vein.
• Parotid head and neck compartment pathology Salivary gland tumors. Metastatic adenopathy. Lymphoma. Parotid cysts.
• Carotid head and neck compartment contents Cranial nerves IX–XII. Sympathetic nerves. Jugular chain nodes. Carotid artery. Jugular vein.
• Carotid head and neck compartment pathology Schwannoma. Neurofibroma. Paraganglionoma. Metastatic adenopathy. Lymphoma. Cellulitis/abscess. Meningioma.
• Masticator head and neck compartment contents Muscles of mastication. Ramus and body of mandible. Inferior alveolar nerve.
• Masticator head and neck compartment pathology Odontogenic abscess. Osteomyelitis. Direct spread of squamous cell carcinoma. Lymphoma. Minor salivary tumor. Sarcoma of muscle or bone.
• Retropharyngeal head and neck compartment contents Lymph nodes (lateral and medial retropharyngeal). Fat.
• Retropharyngeal head and neck compartment pathology Metastatic adenopathy. Lymphoma.
• Prevertebral head and neck compartment contents Cervical vertebrae. Prevertebral muscles. Paraspinal muscles. Phrenic nerve.
• Prevertebral head and neck compartment pathology Osseous metastases. Chordoma. Osteomyelitis. Cellulitis. Abscess.
• Tornwaldt cysts Benign midline nasopharynx lesion of high T2 signal. Believed to be remnant of notochordal tissue (benign).
• Most common minor salivary gland malignancy and has propensity for perineural spread Adenoid cystic carcinoma
• The parapharyngeal space is surrounded by what spaces the carotid space posteriorly, the parotid space laterally, the masticator space anteriorly, and the superficial mucosal space medially. Therefore, the parapharyngeal space will be compressed on its medial surface by masses originating from the mucosal surface, displaced anteriorly by carotid sheath masses, displaced medially by parotid masses, and displaced posteriorly and medially by masses within the masticator space.
• Triad of nasopharyngeal malignancy 1) Mucosal mass of lateral nasopharynx (fossa of Rosenmuller). (2) Lateral retropharyngeal nodes. (3) Mastoid opacification (eustachian tube dysfunction)
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• Head and neck paragangliomas Vascular tumors arising from neural crest cell derivatives. Names given according to location_ Carotid body tumor (at carotid bifurcation). Glomus vagale tumor (vagus nerve). Glomus jugulare tumor (jugular ganglion of vagus nerve). Glomus tympanicum tumor (Arnold and Jacobson nerves of middle ear).
• Salivary gland tumors Benign_ Pleomorphic adenoma. Warthin tumor. Malignant_ Adenocystic carcinoma. Adenocarcinoma. SCC. Mucoepidermoid carcinoma.
• Head and neck trans-spatial disease categories Lymphatic masses (lymphangioma). Neural masses (neurofibroma, schwannoma, perineural spread of tumor). Vascular masses (hemangioma).
• Head and neck diseases that demonstrate perineural spread Fungal infections. Squamous cell carcinoma. Adenoid cystic carcinoma.
• This lymph node chain serves as the final common afferent pathway for lymphatic drainage of the entire head and neck. Internal jugular nodal chain
• Pathologic size of head and neck lymph nodes Jugulodigastric and submandibular nodes may normally measure up to 1.5 cm. All other nodes up to 1.0 cm.
• Common optic nerve sheath complex tumors Optic nerve glioma. Optic sheath meningioma.
• Optic nerve glioma Low grade pilocytic astrocytoma. Most common tumor of optic nerve. Typically occurs during first decade of life. High association with neurofibromatosis type 1. Enlarged sheath complex may be tubular, fusiform, or eccentric with kinking. Rarely calcify.
• Arachnoidal hyperplasia or gliomatosis Thickening of perioptic meninges associated with optic nerve gliomas. Reflects peritumoral reactive meningeal change.
• Optic sheath meningiomas Grow in a linear fashion along optic nerve. Tram track pattern of linear enhancement. May invade through dura. May be extensively calcified.
• Orbital vascular lesions and age groups Capillary hemangiomas, infants (younger than 1 year). Diagnosed within first weeks of life. Lymphangiomas, older group of children (3 to 15 years). Propensity to bleed. Often contain blood degradation products. Cavernous hemangiomas, adults. Sharply circumscribed and round. Venous varix, generally in adults. Dilated vein. Changes with Valsalva maneuver.
• Superior ophthalmic vein pathology Thrombosis often occurs with cavernous sinus thrombosis. Loss of normal flow void. Enlargement occurs with cavernous carotid fistulas.
• Most common cause of intraorbital mass in an adult Idiopathic inflammatory pseudotumor. Inflammatory lymphocytic infiltrate. Involves tendinous attachments to the globe. Often rapidly develops presenting with painful proptosis, chemosis, and ophthalmoplegia.Lymphoma tends to present with painless proptosis.
• 3 common adult intraorbital masses Idiopathic inflammatory pseudotumor. Cavernous hemangioma. Lymphoma.
• Enlargement of extraocular muscles with sparing of tendinous attachments to the globe Thyroid ophthalmopathy (Graves disease). Causes unilateral or bilateral proptosis in adults. Muscles involved, in decreasing order_ IM SLow. Inferior rectus. Medial rectus. Superior rectus. Lateral retus.
• Lesions of the lacrimal gland Inflammatory_ Sarcoidosis. Sjogren syndrome. Neoplastic_ Salivary gland (mixed-cell tumor or adenoid cystic carcinoma). Lymphoma. Pseudotumor. Dermoid (fat-fluid level).
• Retinoblastoma features Most common primary ocular malignancy. Leukocoria. Calcified ocular mass.
• Thyroglossal duct Epithelium-lined tract along which primordial thyroid gland migrates. Extends from foramen cecum (tongue base) to anterior of thyrohyoid membrane and strap muscles to ends at thyroid isthmus. Normally involutes by 8 to 10 weeks of gestation. May give rise to cyst, sinus tract, or ectopic thyroid tissue.
• The usual clinical presentation is that of a painless neck mass along the anterior border of the sternocleidomastoid muscle, presenting during the first to third decade. Second branchial cleft cyst. Anterior to mid sternocleidomastoid muscle. Lateral to internal jugular vein at the level of carotid bifurcation.
• Lymphangiomas Congenital malformations of lymphatic channels. Benign and nonencapsulated. Classified as capillary, cavernous, or cystic. Most present at birth or during infancy.

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