Microscopy November 2018

November’s teaching was quite early in the month, so I hadn’t accumulated many interesting cases. Given the focus on corneas in October, this time round I picked some lid tumours from the archives as well as a few recent cases. Here are a few of them.

Case 1

This is a rapidly growing lid skin lesion in an elderly patient.

Lid skin, medium power

Medium power shows sheets of small blue cells within the dermis with no particular architecture.

Lid skin, high power

Higher power shows easily visible mitoses and a rather smudged appearance to the tumour cells.

Skin tumour, AE1/AE3 immunohistochemistry

AE1/AE3 (a mix of antibodies against various cytokeratins) is positive. In contrast to the uniform highlighting of the (normal) surface epithelium, the immunoreactivity in tumour cells is paranuclear and dot-like.

Skin tumour – synaptophysin immunohistochemistry

Synaptophysin (a neuroendocrine marker) is diffusely positive.

This is Merkel cell carcinoma.

We see very few of these in ophthalmic pathology, and I make no claims to be up to date on the disease. Here are a couple of open access recent review articles:

Becker gives a comprehensive review of both pathogenesis and clinical aspects.

Pulitzer’s review article is more aimed towards diagnostic pathologists.

It’s interesting that immunotherapy is becoming more promising as a treatment option.

Case 2

This is an evisceration specimen

Evisceration – annotated anterior segment

Low power of the anterior segment shows a number of abnormal features

A = subepithelial fibrosis and vascularisation
B = basophilic stippling of Bowman’s layer – calcific band keratopathy
C = stromal scarring with a few inflammatory cells
D = thickened Descemet’s membrane. The detachment is probably perioperative artefact
E = iris is atrophic and scarred with a little inflammation

PAS from evisceration specimen

PAS shows thickened and laminated Descemet’s membrane.

Evisceration specimen – retina

The retina has well preserved photoreceptors. Adherent melanin pigment from RPE suggests this is artefactual (perioperative) rather than true retinal detachment. However, the inner nuclear layer is thinned, and the ganglion cell nuclei absent.

This is congenital glaucoma.

Case 3

Eyelid lump – submitted in two pieces

Eyelid tumour

This piece is obliquely orientated, so some of the apparent epithelial proliferation is artefactual. The dermis has a basaloid tumour with peripheral palisading consistent with nodular basal cell carcinoma.

Eyelid tumour

This other portion is skin is quite inflamed.

Higher power of inflamed dermis

Given the inflammation, proliferating strands within the dermis might run the risk of being mistaken for blood vessels in granulation tissue.

Skin tumour – BerEP4 immunohistochemistry

However, BerEP4 immunohistochemistry is positive. This is basal cell carcinoma with an infiltrative pattern.

Here’s an open access review article by Sunjaya about the use of BerEP4 immunohistochemistry in basal cell carcinoma.

And thinking of wider aspects of lid tumours, here’s an open access review article by Silverman and Shinder on management of eyelid tumours. Be aware it refers to the TNM7 classification rather than current TNM8.

Next month’s session will be on 5 December. Time for some mince pies!

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