Microscopy January 2018

For this month’s microscopy session we had a mixture of attendees: Moorfields trainees, paediatric pathologists, veterinary pathologists and researchers from the Institute of Ophthalmology. Part of the challenge (and fun) about eye pathology is that it lies at the junction of so many different specialist areas. In fact, in some countries, ophthalmic pathology is performed by ophthalmologists rather than histopathologists.

Before I move on to highlighted cases, here are a couple of reminders of other events coming up.

On Wednesday 7 February, Mr John Mould from Eye Veterinary Clinic will be giving a talk titled “Could you make it in veterinary ophthalmology?” You can find further details here

The British Association for Ophthalmic Pathology 2018 meeting will be held in London on 12-13 April. Early bird discount runs until 1 February, and you can find details here.

Case 1

This is a lacrimal gland biopsy from a patient with an orbital mass.

Orbital mass (low power)

On low power, this is a tumour with a rim of lacrimal gland (LG) at the top right. The tumour is biphasic, meaning that it has epithelial and stromal elements.

Lacrimal gland tumour

The epithelial elements include ductal structures (D, containing pink proteinaceous material) and squamous epithelial cysts (KC, containing keratin). Note with the keratin cysts that there is a basal layer at the outer part of the cysts, and flattening of the squamous epithelial cells in the inner part of the cyst where they shed as anucleate keratin flakes. The stroma (S) in this field is myxoid, with loosely distributed spindled and stellate cells.

Chondroid stroma

In this field, the stroma is more cartilage-like (chondroid) with rather glassy stroma and the cell nuclei being present in lacunae (with some clearing around them).
This is a pleomorphic adenoma, a benign tumour. While the term “pleomorphism” might suggest malignancy in a different context (such as nuclear pleomorphism), in this tumour it refers to the varied architecture, which is a reassuring feature.

Case 2

Skin tumour

This is a skin tumour. Nests of tumour extend from the epidermis and infiltrate extensively into the underlying dermis.

On higher power, the cells have copious eosinophilic (pink) cytoplasm and form squamous eddies (SE). The appearance is quite typical of squamous differentiation.

Skin tumour, high power

On this high power view, ,there is focal keratinisation (K), but it is nothing like the keratin flakes in Case 1’s keratin cysts.
This is cutaneous squamous cell carcinoma.

Case 3

This is an enucleation specimen.

Anterior part of enucleation specimen

On low power, the cornea is rather collapsed with flattening of the anterior chamber. This is probably artefactual, as an attempt was made to aspirate tumour from the eye following surgery. Both iris leaflets have a subtle cellular infiltrate which extends into the angle, trabecular meshwork and anterior part of the ciliary body.

Trabecular meshwork is clogged with tumour cells

On higher power, the clogging of the trabecular meshwork (TM) can be seen.

Iris and pupillary margin

This high power view of the pupillary margin shows ectropion uveae, with pigmented epithelium on the anterior surface. There is probable tumour-associated iris rubeosis.
This is ring melanoma of the iris.

There will be no projection microscopy session in February, since I’m giving a Half Day Teaching session at Moorfields (hopefully with a quiz!). The next projection session will be on 13 March. Sign up details will be available nearer the time.

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