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  • Orbits

    • Structural/Congenital

      • Staphyloma

        • Outward bulging of the posterior globe on the temporal side of optic nerve

      • Coloboma

        • Congenital defect in any ocular structure

      • Astrocytic glial hamartomas

        • Can be seen in TS, NF, and vHL

        • Calcifications on retina

        • DiffDx: retinoblastoma

    • Ocular infection

      • Toxocara canis

    • Ocular lesions

      • Retinoblastoma

        • Calcifications in the posterior portion of the globe with extension into vitreous

        • Moderately bright on T1WI and dark on T2WI

      • Persistent hyperplastic primary vitreous

        • Funneled shaped mass (Cloquet canal) between back of the lens and head of optic nerve

        • Microphthalmia

        • Does not calcify

      • Coats disease

        • Telangiectatic vessels leaking serum and protein into retina and subretinal space

        • High density of the vitreous due to exudate

        • Bright on T1WI and bright on T2WI

        • DiffDx: retinoblastoma (dark on T2WI)

      • Toxocara canis

      • Retrolental fibroplasia => result of prolonged oxygen therapy in premature infants

        • Increased density of posteior portion of the globe

      • Melanoma

        • Hyperdense

        • Bright on T1WI, dark on T2WI

      • Choroidal hemangioma

      • Medulloepithelioma

      • Metastases

      • Choroidal osteoma

    • Intraconal

      • Optic nerve lesions

        • Glioma, meningioma, schwannoma, hemangioblastoma, neuritis, sarcoid

        • Devic disease => optic neuritis associated with transverse myelitis

      • Tolosa-Hunt syndrome => painful ophthalmoplegia caused by nonspecific inflammation of the cavernous sinus or superior orbital fissure.

      • Optic nerve glioma

        • Radiographically, can not be separated from the nerve

        • Arachnoidal granulamatosis (perineural glial proliferation) => a feature of optic gliomas in neurofibromatosis

      • Optic nerve sheath meningioma

        • Nerve may be visualized

      • Cavernous/capillary hemangioma

      • Orbital venous anomalies

        • Orbital varix

        • Lymphangioma

      • Carotid-cavernous fistula

      • Dural vascular malformation

    • Conal

      • Thyroid ophthalmopathy

        • Inferior and medial rectus are most commonly affected

        • Most common single pattern is enlargement of all muscles

      • Orbital pseudotumor (Tolosa-Hunt syndrome)

      • Sarcoidosis

      • Wegener's granulomatosis

        • Homogenously enhancing mass with associated sinus disease and bone destruction

      • Kimura disease

        • Similar to orbital pseudotumor but with skin findings in young Asian males

      • Orbital lymphoma

        • Molds around the orbit

        • DiffDx: pseudotumor

      • Posttransplantation lymphoproliferative disorder

        • Can destroy bone

    • Extraconal lesions

      • Infection

      • Lacrimal sac lesions

        • Dacryocystitis

        • Papilloma - has malignant degeneration potential

      • Lacrimal gland lesions

        • Mikulitz syndrome => non-specific swelling of lacrimal and salivary glands associated with sarcoid, TB and leukemia.

        • Sjogren's syndrome => lymphocytic infiltration of lacrimal and salivary glands associated with connective tissue disorders

        • Lymphoid tumors (usually does not produce bony erosion)

        • Epithelial tumors (generally involve bone)

          • Pleomorphic adenomas

          • Malignant adenoid cystic carcinoma

        • Transitional cell carcinoma

      • Dermoids

      • Orbital rhabdomyosarcoma

      • Lymphangioma

      • Fibrous histiocytoma

      • Metastasis

        • Scirrhous breast carcinoma => infiltrative retrobulbar mass with enophthalmos from desmoplastic reaction

      • Sphenoid wing meningioma

        • DiffDx: fibrosseous lesions such as ossifying fibroma, osteoma, sclerotic metastases such as prostate metastases, fibrous dysplasia

      • Bone lesions

        • Fibrous dysplasia

        • Paget's

        • EG

        • Fibroosseous lesions

          • Osteoma

          • Ossifying fibroma

          • Osteoblastoma

          • Osteosarcoma

          • Osteoclastoma

          • Brown tumor of hyperparathyoidism

          • ABC

          • Giant cell reparative granuloma

            • Probably a reaction to intraosseous hemorrhage

            • May contain fluid levels

  • Nasal region

    • Prenasal mass

      • Dermoid/epidermoid cyst

      • Encephalocele

      • Hemangioma

      • Glial heterotopia

  • Mandible

    • Cystic masses

      • Odontogenic cysts

        • Radicular cyst

        • Dentigerous cyst

          • Formed by excessive accumulation of fluid between enamel and dental capsule

          • Well corticated pericoronal radiolucency

        • Odontogenic keratocyst

          • Aggressive cystic jaw lesion

            • Perforation of bone cortex

            • Scalloped corticated border

            • Large size

          • Associated with basal nevus syndrome

        • Botryoid cyst => developmental lateral periodontal cyst

      • Non-odontogenic cyst

        • Solitary simple hemorrhagic bone cyst

        • Static bone cavity => Stafne cyst

    • Benign tumors

      • Ameloblastoma

      • Odontoma

      • Fibromyxoma

      • Cementoma

    • Malignant tumors

      • Odontogenic

        • Odontogenic carcinoma

        • Odontogenic sarcoma

      • Non-odontogenic

        • Osteosarcoma

        • Chondrosarcoma

        • Ewing's sarcoma

        • Multiple myeloma

      • Metastases

        • Carcinoma (breast, lung, renal)

        • Sarcoma

  • Ear/Temporal Bone

    • Middle Ear
      • Anatomy
        • Malleus
          • Manubrium
          • Neck
          • Anterior process
          • Head
        • Incus
          • Body
          • Long process
          • Lenticular process
          • Short process
        • Stapes
          • Head
          • Neck
          • Anterior crus
          • Posterior crus
          • Footplate
      • Developmental
        • Bony bars
        • Oval window atresia
        • Fenestral otospongiosis
      • Inflammatory
        • Cholesteatoma
          • Acquired from perforation of tympanic membrane
          • Congenital from epidermoid formation
        • Tympanosclerosis
        • Resorptive osteitis
      • Masses
        • Benign
          • Hemangioma - most common benign mass in pediatric patients
          • Facial nerve neuroma
          • Paraganglioma - most common benign mass in adult patients
          • Cholesterol granuloma
        • Malignant
          • Squamous cell carcinoma
      • Trauma
        • Fractures
        • Dislocations
          • Incus is most common
    • CPA

      • Schwannoma

      • Arachnoid cyst

      • Meningioma

      • Epidermoid

    • Petrous Apex

      • Mucocele

      • Cholesterol granuloma

      • Multiple myeloma

      • Metastasis

      • Schwannoma

      • Enchondroma/Chondrosarcoma

      • Apical petrositis

      • Xanthoma