ABO Oculoplastic & Orbit 2 — Questions and Answers
Question 1: Which extraocular muscle is most commonly enlarged in thyroid eye disease?
- Lateral rectus
- Superior oblique
- Inferior rectus (Correct answer)
- Superior rectus
Correct answer: Inferior rectus
The inferior rectus is most frequently involved, followed by the medial, superior, and lateral recti.
Question 2: On orbital CT, enlargement of an extraocular muscle that includes the tendon insertion is most characteristic of which condition?
- Idiopathic orbital myositis (Correct answer)
- Thyroid eye disease
- Carotid-cavernous fistula
- Acromegaly
Correct answer: Idiopathic orbital myositis
Orbital myositis typically involves the tendon, whereas thyroid eye disease classically spares it.
Question 3: What is the most common benign orbital mass in adults?
- Schwannoma
- Cavernous venous malformation (cavernous hemangioma) (Correct answer)
- Solitary fibrous tumor
- Lymphangioma
Correct answer: Cavernous venous malformation (cavernous hemangioma)
Cavernous venous malformation is the most common benign orbital lesion in adults, typically a well-circumscribed intraconal mass in middle-aged women.
Question 4: A 7-year-old presents with rapidly progressive unilateral proptosis and superior orbital mass over 2 weeks. What is the most likely primary orbital malignancy?
- Neuroblastoma
- Retinoblastoma
- Langerhans cell histiocytosis
- Rhabdomyosarcoma (Correct answer)
Correct answer: Rhabdomyosarcoma
Rhabdomyosarcoma is the most common primary orbital malignancy of childhood and often presents with rapid proptosis, frequently superonasally.
Question 5: What is the current first-line systemic treatment for a periocular infantile hemangioma causing amblyopia risk?
- Oral propranolol (Correct answer)
- Oral prednisolone
- Intralesional triamcinolone
- Interferon alfa
Correct answer: Oral propranolol
Oral propranolol has replaced corticosteroids as first-line systemic therapy for vision-threatening infantile hemangiomas.
Question 6: An S-shaped upper eyelid deformity with a 'bag of worms' palpable texture is most characteristic of which lesion?
- Lymphatic malformation
- Capillary hemangioma
- Plexiform neurofibroma (Correct answer)
- Orbital varix
Correct answer: Plexiform neurofibroma
Plexiform neurofibroma, pathognomonic of neurofibromatosis type 1, produces an S-shaped lid and a 'bag of worms' feel.
Question 7: A 'tram-track' pattern of calcification along the optic nerve on CT is most suggestive of which diagnosis?
- Optic nerve glioma
- Optic nerve sheath meningioma (Correct answer)
- Optic neuritis
- Orbital lymphoma
Correct answer: Optic nerve sheath meningioma
Optic nerve sheath meningioma shows tubular enhancement or calcification of the sheath around a spared nerve, producing the tram-track sign.
ABO Oculoplastic & Orbit 2
Which extraocular muscle is most commonly enlarged in thyroid eye disease?