Cysts of Pneumocystis jiroveci (formerly carinii) in bronchoalveolar lavage, Grocott’s methenamine silver stain.

In this induced argentaffin reaction, chromic acid oxidation forms aldehydes from fungal cell wall polysaccharide components. The reaction is similar to the Periodic acid Schiff reaction, but since the chromic acid is a much stronger oxidizer, background staining by collagen and basement membrane is suppressed (they are oxidized past the aldehyde stage).  The aldehyde groups then react with the silver nitrate, reducing it to a metallic silver, thus blackening the site.

It can be a bit tricky to time since different organisms take up stain at different rates. Pneumocystis can be missed if you understain, but other organisms will come out a black blob (thus making it impossible to see the internal structure) if you overstain.

Onion bulb structures, toluidine blue stain.

Hypertrophic changes with onion-bulb formation occur most commonly as a result of recurrent segmental demyelination and are most often seen in hereditary neuropathies (such as the fairly common Charcot-Marie-Tooth disease). The schwann cell doesn’t wrap around the axon properly and as a result, you get these strange involutions in the histological section.

Cystadenoma of the ovary, Masson Trichrome. 

This cyst is an ingrowth on the ovary surface, the capsule tissue that normally surrounds the ovary is seen at right (light blue). As an adenoma it consists of epithelial cells derived from glandular ovarian tissue. The cavities of the glands fill with mucous produced by the epithelial cells. 

The other day, a coworker grossed one that was a 5kg beast. Cutting into it was interesting to say the least.

Fetal vertebra, combined Alcian Blue and Periodic Acid Schiff stain.

Basal cell carcinoma, false colored section. Cells within the tumour are purple and have an abnormal arrangement. The skin surface is at top (red).

When I made my visit to a very good Mohs clinic in town (not as a patient), there was an elderly gentleman with a horn on his head. By which I mean he had a grey-black tumor the size of a very large egg on the top of his head which was actually shaped like a broken horn. He had spent years hiding it under a hat and had no family and friends to push him to see a doctor about it until that day.

When the doctor cut into it, the massive amount of necrotic tissue underneath stunk so badly, it knocked out the nurse in the room. It was… well, it was something else.

Uterine fibroid, H&E stain.

I try to avoid fresh tissues on this blog; it’s just a thing. In any case, for a lot of greenhorns (and not so greenhorns) in healthcare, the question of “how did the patient let it get so bad?” seems to come up a lot. Actually, I’m pretty sure this will never go away no matter how old I get, considering I don’t normally get the liberty of asking.

Case in point (one of many to come, I promise), not too long ago, I opened up a bucket in histo grossing and there was a fibroid sized just smaller than a basketball that was taken out of someone’s abdomen. 

Collagenous colitis in a section of large intestine, Masson’s Trichrome stain using aniline blue as the counter(/collagen) stain. 

Hyaline cartilage, H&E stain.

Though the photo’s not part of the trachea, the first time I saw this was in a section of trachea. I immediately had one of those trainwreck moments. “Euuuugh, it’s like thousands of eyes staring back at me this is so gross thisistheworstpartofhistoever!” but never managed to look away. I got over it quickly enough. There are worse things in histo, like 4AM shifts (I can do mornings, just not that kind of morning). Plus you don’t even really use your microanatomy in the end. 

Movat’s pentachrome stain. We don’t use it in our region, but it’s nice to look at once in a while because all the pinks and purples in routine hematoxylin and eosin are not very exciting.