Ch 41. Subepithelial neoplasms of the conjunctiva.

Question 1

Where are dermoid tumors usually located?

Answer 1

Inferotemporal limbus

Question 3

How can you make the clinical distinction between a dermolipoma and its main Dxdx?

_{(prolapsed orbital fat, prolapse of the palpebral lobe of the lacrimal gland, and lymphoma)}

Answer 3

The former is firmly attached to the underlying sclera, the latter are all freely mobile.

Question 4

What types of choristomas can be found in the conjunctiva?

Answer 4

• dermoid
• dermolipomas
• ectopic lacrymal glands (simple or complex, the latter including cartilage, smooth muscle, nerve elements, sweat glands or pilosebaceous units)
• Epibulbar osseous choristoma.
• Neuroglial choristomas.

Question 5

In the evaluation of a patient with possible hemorrhagic lymphangiectasia, why is it important to define the previous state (lymphangiectasia that has filled with blood vs an actual telangectasia)?

Answer 5

Lymphangiectasia are mostly congenital (acquired in cases of trauma or chronic inflammation), treatment is straightforward by excision or diathermy. They have no significant associations.

Telangiectasias, on the other hand, are associated with systemic syndromes: ataxia-telangiectasia (Louis-Bar syndrome), Bloom syndrome, and hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease) in which there are epibulbar and interpalpebral telangiectasias of the arteries without an associated lymphatic component_.

• _{The conjunctival lesions of the Louis-Bar syndrome are a marker for associated cerebellar abnormalities and immunologic derangements (e.g. hypogammaglobulinemia), which are conducive to sinopulmonary infection and lymphoreticular proliferations, particularly T-cell leukemias.}
• _{Bloom syndrome is an autosomal recessive condition caused by a mutation of the BLM gene on chromosome 15 (15q26.1). Most common in Ashkenazi Jews, it is associated with increased susceptibility to cancer and infections, photosensitivity, and growth retardation.}
• _{Patients with hereditary hemorrhagic telangiectasia, or Rendu-Osler-Weber disease, have dilated vessels due to abnormalities in vascular wall repair which increases susceptibility to bleeding from the skin and mucous membranes, CNS, lungs, and other vital organs. It is an autosomal dominant disorder produced by an abnormality in one of two genes (chromosomes 9q33–34 and 12q13) involved in vessel wall repair. In these conditions, the epibulbar vascular lesions do not acquire a tumefactive character (hamartia) because they are simple telangiectasias that grow with the patient and the eyeball. Episodic events such as hemorrhage or swelling also are not encountered}

Question 6

Can molluscum contagious affect the conjunctiva?

Answer 6

Direct infection is rare (it usually presents secondary keratoconjunctivitis associated with palpebral infection) But has been reported in immunosuppressed patients.

Question 7

Biochemically, how can amyloid be divided?

Answer 7

• Amyloid B: Composed of immunoglobulins, present in primary amyloidosis and plasma cell dyscrasias.
• Amyloid A: unknown composition, present in all the other forms.

Question 8

Is conjunctival amyloidosis associated with systemic diseases?

Answer 8

No, it is almost always isolated, associated with trauma or local inflammation.

Question 9

Can a conjunctival hemorrhage simulate melanoma?

Answer 9

Yes, particularly in the rare cases in which a hematic cyst is formed, it may not reabsorb and turn into a brown lesion that may require surgical excision for cosmesis and definitive diagnosis if the previous state is unknown.

Question 10

Which is the most frequent orbital mesenchymal tumor?

Answer 10

Fibrous histiocytoma.

although rare, it may also arise in the conjunctiva, episclera, and sclera.

Question 11

Given that this lesions are freely mobile, what is your most likely diagnosis?

Answer 11

subconjunctival limphoma.

_{Subconjunctival lymphoma. (A and B) Both of these patients presented with asymptomatic, sharply demarcated, salmon-colored, subconjunctival masses. A fine vascularity is associated with these lesions and contributes to their color. These lesions are freely mobile over the underlying sclera. The salmon-colored nature of these lesions is often best demonstrated using natural sunlight, as the intensity of ophthalmic slit lamps often washes out the color of these lesions. (C) A similar lesion that involves both the inferior bulbar and fornicial conjunctiva. (D) This lesion involves the inferior palpebral and fornicial conjunctiva. Clinically, it appears to be composed of clusters or follicles.}