ORBIT



Intraconal Lesion with Optic Nerve Involvement


1.   Optic nerve glioma


2.   Optic nerve sheath meningioma (10% of orbital neoplasm)


3.   Optic neuritis


4.   Inflammatory pseudotumor (may surround optic nerve)


5.   Sarcoidosis


6.   Intraorbital lymphoma (may surround optic nerve, older patient)


7.   Elevated intracranial pressure


→  distension of optic sheath


√  bilateral tortuous enlarged optic nerve-sheath complex


OPTIC NERVE TRAM-TRACK SIGN


1.   Optic nerve sheath meningioma


2.   Orbital pseudotumor


3.   Perioptic neuritis


4.   Perioptic hemorrhage


5.   Sarcoidosis


6.   Lymphoma / leukemia


7.   Metastasis


8.   Erdheim-Chester disease = systemic xanthogranulomatosis


Intraconal Lesion without Optic Nerve Involvement


1.   Cavernous hemangioma


2.   Orbital varix


3.   Carotid-cavernous fistula


4.   Arteriovenous malformation


least common of orbital vascular malformations (congenital, idiopathic, traumatic)


√  irregularly shaped intensely enhancing mass of enlarged vessels


√  associated with dilated superior / inferior ophthalmic v.


5.   Hematoma


6.   Lymphangioma


7.   Neurilemmoma


√  commonly adjacent to superior orbital fissure, inferior to optic nerve


√  local bone erosion


8.   Rhabdomyosarcoma (mostly extraconal)


Extraconal lesion


Extraconal-intraorbital Lesion


A.  BENIGN TUMOR


1.   Dermoid cyst


2.   Teratoma


<  1% of all pediatric orbital tumors


√  ± areas of fat, cartilage, bone


√  expansion of bony orbit ± bone defect


3.   Capillary hemangioma


4.   Lymphangioma


5.   Plexiform neurofibroma


6.   Inflammatory orbital pseudotumor


7.   Histiocytosis X


lesion usually arises from bone


B.  MALIGNANT TUMOR


1.   Lymphoma / leukemia


2.   Metastasis


3.   Rhabdomyosarcoma


mnemonic:   MOLD


Metastasis


Others (rhabdomyosarcoma, lymphangioma, sinus lesion)


Lymphoma, Lacrimal gland tumor


Dermoid


Extraconal-extraorbital Lesion


A.  FROM SINUS


maxillary / sphenoid sinuses are rare locations of origin


1.   Tumor:


squamous cell carcinoma (80%), lymphoma, adenocarcinoma, adenoid cystic carcinoma


2.   Mucocele


3.   Paranasal sinusitis:


◊  Most common cause of orbital infection!


Origin:   from ethmoid sinuses (in children), from frontal sinus (in adolescence)


√  preseptal / orbital edema / cellulitis


√  subperiosteal / orbital abscess


√  mucormycosis (in diabetics) destroys bone and extends into cavernous sinus
































Cx: (1) Epidural abscess
  (2) Subdural empyema
  (3) Cavernous sinus thrombosis
  (4) Meningitis
  (5) Cerebritis
  (6) Brain abscess

B.  FROM SKIN


1.   Orbital cellulitis


C.  FROM LACRIMAL GLAND


√  mass arising from superolateral aspect of orbit


Dilatation of Superior Ophthalmic Vein


1.   Carotid-cavernous sinus fistula


2.   Cavernous sinus thrombosis


3.   Venous varix


4.   Graves disease


5.   Normal variant


ORBITAL MASS


Orbital Mass in Adults


(a)  vasculogenic orbital mass


1.   Cavernous malformation


2.   Hemangiopericytoma


(b)  lymphoproliferative orbital lesion


1.   Typical / atypical lymphoid hyperplasia


2.   Lymphoma of orbit


(c)  lacrimal gland lesion (5–14% of biopsied orbital masses)


›  epithelial (largely neoplastic) lesion (40–50%)


1.   Pleomorphic adenoma


2.   Adenoid cystic carcinoma


›  nonepithelial lesion


1.   Dacryoadenitis


2.   Lacrimal gland lymphoma


(d)  optic nerve & meningeal lesions


1.   Optic pathway glioma


2.   Optic nerve sheath meningioma


(e)  peripheral nerve sheath lesions


1.   Schwannoma (rare)


2.   Neurofibroma


3.   Malignant peripheral nerve sheath tumor


(f)  Primary orbital melanoma


(g)  Metastasis to orbit


Orbital Mass in Childhood












































1. Dermoid cyst 46%
2. Inflammatory lesion 16%
3. Dermolipoma   7%
4. Capillary hemangioma   4%
5. Rhabdomyosarcoma   4%
6. Leukemia / lymphoma   2%
7. Optic nerve glioma   2%
8. Lymphangioma   2%
9. Cavernous hemangioma   1%

mnemonic:   LO VISHON


Leukemia, Lymphoma


Optic nerve glioma


Vascular malformation: hemangioma, lymphangioma


Inflammation


Sarcoma: ie, rhabdomyosarcoma


Histiocytosis


Orbital pseudotumor, Osteoma


Neuroblastoma


Osseous Orbital Lesion in Children


(a)  development of the osseous orbit


1.   Dermoid inclusion cyst


2.   Epidermoid inclusion cyst


(b)  primary bone lesions


1.   Fibrous dysplasia


2.   Juvenile ossifying fibroma


3.   Cementifying fibroma


4.   Langerhans cell histiocytosis


(c)  malignant tumors involving multiple sites


1.   Granulocytic sarcoma


2.   Hematogenous metastasis: neuroblastoma (most common primary tumor to involve orbit)


(d)  primary malignant bone tumor


1.   Osteosarcoma


Nonosseous Lesion of Extraocular Orbit in Children


1.   Rhabdomyosarcoma


2.   Infantile hemangioma


3.   Lymphangioma


4.   Infantile fibromatosis


Primary Malignant Orbital Tumors
























1. Retinoblastoma 86.0%
2. Rhabdomyosarcoma   8.1%
3. Uveal melanoma   2.3%
4. Sarcoma   1.7%

Only gold members can continue reading. Log In or Register to continue

Jun 29, 2017 | Posted by in GENERAL RADIOLOGY | Comments Off on ORBIT
Premium Wordpress Themes by UFO Themes