Moorfields HDT – December 2016

Yesterday’s teaching included a tour of the department, where participants got to try their hand at embedding tissue and picking up sections from the waterbath, followed by a microscopy session with some interesting cases from the last month.

Here are a few highlights.

Case 1
Slow growing lid lesion in an elderly male.

Skin biopsy
Skin biopsy

This is skin including a basaloid epithelial tumour with central necrosis. There is palisading of the tumour cells, especially close to the epidermis (on the left). This is a typical nodular basal cell carcinoma.


Case 2
Conjunctival cyst in a middle aged male.

Conjunctival cyst low power
Conjunctival cyst low power

This conjunctival specimen shows prominent cyst formation, accounting for the clinical appearance.

Conjunctival cyst higher power
Conjunctival cyst higher power

On higher power, there are nests of naevus cells. Conjunctival naevi often have cysts associated with the stromal component. In this case, the cysts are particularly prominent.


Case 3
Orbital mass in a child.

Orbital tumour
Orbital tumour

This is fibrofatty tissue, with fat cells visible on the right. The specimen is infiltrated by a “small round blue cell tumour” with no particular architecture. There differential diagnosis is wide, and immunohistochemistry is required.

Immunohistochemistry for MyoD1
Immunohistochemistry for MyoD1

In this case, MyoD1 immunohistochemistry is strongly positive, confirming a diagnosis of rhabdomyosarcoma.


Case 4
Perforated cornea

Cornea
Cornea

The epithelium (top) is unhealthy and discohesive. Even on haematoxylin and eosin stain, numerous rounded structures can be seen within the stroma. In the deeper stroma there is apoptotic debris and inflammatory cells.

Acanthamoeba immunohistochemistry
Acanthamoeba immunohistochemistry

Acanthamoeba immunohistochemistry confirms the presence of large numbers of cysts. This is a particularly striking case of Acanthamoeba keratitis.

We also reiterated the requirement to submit histology specimens in formalin (don’t try to get clever!) and also the usefulness of providing relevant clinical information on the request form. Unfortunately this doesn’t always happen!

I hope the teaching was useful, and I’ll be running another microscopy session in January.

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