Microscopy teaching July 2018

A quiet microscopy session this month, with summer holidays and hospital changeover coming up. I rather welcomed it since I’m a bit distracted with the release of my first novel . Don’t worry, I’ll stop going on about it, eventually, but I’m still at the excited stage!

It was lovely to have Nicole Carnt attending from UNSW Sydney. Nicole is a researcher with an interest in immunology of anterior ocular infections and last week hosted the 6th Acanthamoeba Keratitis Patient event at Moorfields Eye Hospital.

We started with a review of lid anatomy, paying particular attention to the location and significance of the meibomian gland and then covered cornea, anterior segment and (very briefly!) the posterior segment.

There was a bit more chat and a bit less in the way of case discussion this month since we got sidetracked into a conversation about Fuchs’ (or Fuchs’-like) dystrophy in dogs as well as discussion about macroscopic handling of specimens. Those of you attending my Moorfields Half Day Teaching session on 8 August will have a chance to see the latter – but no dogs!

Here are a few of the cases we talked about:

Case 1

Cornea (penetrating keratoplasty)

This diagnosis has cropped up a few times before on this blog, but it’s a fairly common condition.

Low power view of cornea

A low power view shows full thickness cornea with slight epithelial thickening over thinned stroma. Most noticeable in the posterior part of the specimen are two partly detached thin structures.

PAS of cornea

A higher power with a PAS stain highlights one of these structures and confirms it to be a scroll of Descemet’s membrane, supporting previous disruption.

High power view of Bowman’s layer

If we return to the anterior part of the cornea on higher power still, there is a break in Bowman’s layer (asterisked).

This is keratoconus, and the Descemet’s break reflects a previous episode of hydrops.

Case 2

Orbital mass

Another old favourite – remember, I don’t post very uncommon diagnoses on this blog. You have to attend the session in person to see those 🙂

Low power orbital mass

A low power view shows a pseudoencapsulated tumour nodule with a rim of lacrimal gland (on the right). Even at low power, the tumour appears to have mixed architecture with cystic and more solid areas as well as hypo- and hypercellularity.

Medium power orbital mass

This higher power image shows ductal structures and spindled cells, the latter in a myxoid (pale basophilic) stroma.

Medium power orbital mass

In this image, the stroma is more solid with spindle cells and a couple of squamous whorls. There is a single mitosis.

This is a pleomorphic adenoma.

Case 3

Orbital mass

In contrast, this is a less common orbital tumour.

Low power orbital mass

At low power, the overall architecture is quite uniform, especially compared to Case 2. Tumour cells form small nests and trabeculae with duct-like spaces.

Higher power of cribriform architecture

In areas, the architecture is cribriform, with solid tumour nests punctuated by multiple cystic spaces. This is often described as a “Swiss cheese” appearance.

Perineural infiltration

A higher power view shows tumour cells infiltrating a nerve (asterisked). This helps to explain the pain patients often experience with this tumour as well as a tendency for the tumour to spread.

This is adenoid cystic carcinoma.

There will be no microscopy session next month because of the Moorfields Half Day Teaching, but we should be back to our usual schedule in September.

Have a great summer!

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