Malignant Tumors of Conjunctiva

Malignant Conjunctival Tumors - Eye's Bad Actors

• Scope: Malignancies arising from conjunctival epithelium or melanocytes.
• Risk Factors: UV exposure (esp. UVB), HPV (types 16, 18 for SCC), fair skin, xeroderma pigmentosum, HIV.
• Major Types:
  • Conjunctival Squamous Cell Carcinoma (SCC): Most common. Often arises from CIN. Locally invasive.
  • Conjunctival Melanoma: Arises from PAM (75%), nevus (20%), or de novo (5%). High metastatic potential.

    ⭐ Most conjunctival melanomas arise from Primary Acquired Melanosis (PAM) with atypia.

  • Conjunctival Lymphoma: Usually MALT type, salmon-pink patches, often bilateral in systemic lymphoma.

Conjunctival Squamous Neoplasia - Scaly Invaders

Ocular Surface Squamous Neoplasia (OSSN) encompasses a spectrum from Conjunctival Intraepithelial Neoplasia (CIN) to invasive Squamous Cell Carcinoma (SCC).

• Risk Factors: UV-B exposure (key), Human Papillomavirus (HPV types 16, 18), HIV, smoking.
• Clinical Features:
  • Location: Limbus (most common, interpalpebral area).
  • Appearance: Leukoplakic (white patch), gelatinous, or papillomatous mass.
  • Feeder vessels often prominent.
  • Stains with Rose Bengal dye.
• Diagnosis: Excisional biopsy (gold standard for histopathology), impression cytology.

• Management Options:
  • Surgical: Excision with 4 mm margins + cryotherapy (adjunctive, "no-touch" technique).
  • Topical Chemotherapy: Mitomycin C (MMC), 5-Fluorouracil (5-FU), Interferon α2b (IFN α2b).
  • Radiotherapy (e.g., plaque brachytherapy for recurrences/extensive disease).

⭐ Most OSSN lesions arise at the limbus, the junction of cornea and sclera, typically within the sun-exposed interpalpebral fissure. This location highlights UV radiation as a major etiological factor.

Conjunctival Melanoma - Pigment Perils

• Most lethal conjunctival tumor, from melanocytes.
• Origins:
  • Primary Acquired Melanosis (PAM) with atypia: 50-75% (most common)
  • Pre-existing nevus: 20-30%
  • De novo: ~20%
• PAM with atypia: Unilateral, flat, brown patches. Biopsy if suspicious.
  • Progression risk with atypia: ~13%.
• Clinical Features:
  • Pigmented (common) or amelanotic nodule.
  • Irregular borders, feeder vessels.
  • Location: Limbus > fornix > tarsal conjunctiva.
• Prognosis: Breslow thickness key. Mortality ~25% (10yr).
• Treatment: Wide excision, cryotherapy, topical chemo (MMC, IFN α-2b). SLNB if >2mm thick.

⭐ PAM with atypia is the most common precursor, accounting for up to 75% of conjunctival melanomas.

Conjunctival Lymphoma & Others - Cellular Crowds

• Conjunctival Lymphoma
  • Most common orbital adnexal lymphoma; typically Non-Hodgkin B-cell (MALT type ~80%).
  • Presentation: Painless, salmon-pink, fleshy ("fish-flesh") infiltrative mass.
  • Site: Superior fornix common. Bilateral in 20%.
  • Diagnosis: Biopsy (Immunohistochemistry: CD20+, CD43+, CD5-, CD10-).
  • Treatment:
    • Localized disease: External Beam Radiotherapy (EBRT) - gold standard.
    • Other options: Rituximab (intralesional/systemic), cryotherapy, chemotherapy (for systemic disease).

    ⭐ Conjunctival MALT lymphoma has an excellent prognosis with localized radiotherapy; systemic workup is crucial.

• Kaposi Sarcoma
  • Vascular tumor (HHV-8); common in AIDS (CD4 < 200/μL).
  • Appearance: Cherry-red to violaceous, flat or nodular lesion.
  • Treatment: HAART; Local options: radiotherapy, cryotherapy, excision, intralesional vinblastine.
• Other Rare Tumors
  • Metastatic carcinoma (e.g., from breast, lung): Rare, poor prognosis.

High‑Yield Points - ⚡ Biggest Takeaways

• Conjunctival SCC, most common, arises from CIN; UV exposure & HPV are key risks.
• SCC often appears as a limbal, gelatinous, or leukoplakic mass in the interpalpebral fissure.
• Treatment: Excisional biopsy, cryotherapy, topical chemotherapy (Mitomycin C, Interferon).
• Conjunctival Melanoma is rare but aggressive; can arise from PAM with atypia or de novo.
• Melanoma prognosis depends on tumor thickness, ulceration, and location (non-limbal worse).
• Kaposi's Sarcoma: bright red vascular lesion, common in AIDS patients.