Surface tumours, uveal metastases and benign mimics
Key Takeaways
OSSN ranges from epithelial dysplasia to invasive carcinoma, so depth and margins matter.
Clinical conjunctival pigmentation labels do not substitute for histological grading.
Choroidal metastases may be multifocal or bilateral and can reveal previously unrecognized systemic cancer.
Benign hamartomas, choristomas and vascular lesions can still cause major visual complications.
Describe growth, location and tissue involvement
An ocular mass may be epithelial, melanocytic, vascular, lymphoid, metastatic or developmental. Document its site, dimensions, pigmentation, vascularity, surface change and growth using examination and photographs. A pigmented lesion is not automatically melanoma, and an amelanotic lesion is not automatically benign. New nodularity, fixation, feeder vessels or corneal involvement can change the diagnostic priority.
Evert lids and examine fornices when assessing conjunctival disease. A visible bulbar lesion may be only part of the process. Anterior-segment optical coherence tomography can help define epithelial thickening, but it cannot reliably replace histology for all questions of invasion or tumour type. Plan sampling and treatment with an ocular oncology service when malignancy is suspected.
Ocular surface squamous neoplasia
Ocular surface squamous neoplasia (OSSN) encompasses epithelial dysplasia, in situ carcinoma and invasive squamous carcinoma. A limbal gelatinous, papilliform or leukoplakic lesion with corneal epithelial extension is suggestive, but pterygium, papilloma and other lesions can resemble it. Ultraviolet exposure and immune compromise are relevant risk factors without establishing the diagnosis in an individual.
Treatment can include a planned excision with margin assessment and selected cryotherapy, topical therapy or a combined approach. Topical agents include 5-fluorouracil, mitomycin C and interferon-based treatment where available and appropriate. Choice follows extent, suspected invasion, prior treatment and tolerance. Surface toxicity, punctal injury and limbal damage matter; do not present these agents as harmless drops or assume one regimen is universally available across Europe.
Visible regression does not remove the need for surveillance. A deep or atypical lesion may require tissue diagnosis even if an imaging pattern suggests epithelial disease. Recurrent disease and poor response should prompt reassessment of extent and diagnosis rather than indefinite repetition of the same course.
Conjunctival melanocytic lesions
A naevus often presents earlier in life and may contain cysts, commonly on bulbar conjunctiva. Acquired flat pigmentation has several causes, including melanocytic intraepithelial lesions with variable atypia. Clinical labels such as primary acquired melanosis do not by themselves specify the histological grade. Current pathology terminology and the report distinguish low- and high-grade intraepithelial disease and invasive melanoma.
Conjunctival melanoma can arise in different settings and can spread through lymphatic as well as haematogenous routes. Map extent, examine regional nodes and assess deeper involvement. A planned oncological excision differs from casually shaving a lesion at the slit lamp. Adjunctive treatment and surveillance depend on histology, margins, site and stage. Amelanotic melanoma remains in the differential of a suspicious fleshy mass.
| Lesion category | Key distinction | Management implication |
|---|---|---|
| Epithelial atypia | In situ versus stromal invasion | Depth and margin assessment |
| Melanocytic pigmentation | Benign lesion versus graded atypia or invasion | Histological classification and mapping |
| Salmon-coloured infiltrate | Reactive or lymphoid neoplasia | Planned biopsy and systemic staging |
| Vascular fleshy mass | Reactive granuloma or vascular tumour | Clinical context and selective sampling |
Uveal metastases and amelanotic lesions
Choroidal metastases often appear creamy or yellow and can be multifocal, bilateral or associated with subretinal fluid. Breast and lung malignancies are important primary sources, but an ocular lesion may precede recognition of the systemic tumour. Coordinate systemic investigation and oncology care. Do not assume that every solitary amelanotic choroidal lesion is a melanoma.
Ultrasound, OCT and selected angiography help characterize size, internal appearance and associated fluid. Differential diagnoses include melanoma, haemangioma, osteoma and inflammatory granuloma. Biopsy is selected when it will resolve an important uncertainty or guide care. Treatment may involve systemic cancer therapy, ocular radiotherapy or other local measures, chosen according to symptoms, visual potential and systemic prognosis.
Hamartomas, choristomas and vascular lesions
A hamartoma is disorganized overgrowth of tissue native to the site; a choristoma contains tissue not normally found there. A limbal dermoid is a choristomatous lesion and may affect refraction and cause amblyopia. Retinal astrocytic hamartomas can be associated with tuberous sclerosis but also occur in other settings. Retinal capillary haemangioblastomas raise consideration of von Hippel–Lindau disease according to age, number and systemic context.
Circumscribed choroidal haemangioma can cause exudation and visual loss, whereas diffuse choroidal haemangioma may occur with Sturge–Weber syndrome. Observation or treatment follows symptoms and anatomy. Benign histology does not mean a lesion cannot cause serious visual morbidity through exudation, glaucoma or refractive distortion.
Case response
A growing limbal leukoplakic mass needs OSSN assessment and a plan for invasion and margins. A new pigmented nodule requires a melanocytic differential with mapping. Bilateral creamy choroidal lesions require metastatic consideration and systemic coordination. State the tissue category, the uncertain feature and the investigation that changes treatment.
Sources: RCPath conjunctival melanoma dataset and primary OSSN treatment comparison.
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