Heck Yeah Cytology!

A fine assortment of interesting, perplexing, and down right awesome things from the world of veterinary hematology and cytology...

Rib mass from a 6 year-old, male-castrated Golden Retriever.  The owner felt a relatively firm mass along one of the patient’s ribs while petting the dog.  On evaluation the mass was about 2.0 x 2.0cm in size and firmly adhered to the rib.  Additionally the mass appeared non-painful on manipulation and was not warm to the touch.  Here is what we got on needle aspirates!

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Alright, your eyes are immediately drawn to the gorgeous magenta material!  The slides were just loaded with this beautiful material - which likely represents matrix made by all those spindle-shaped cells.  The matrix could be chondroid from cartilage, bone, or even a mucous-like material (termed myxoid).  My vote was for chondroid.  The spindle cells are easiest to see on the last image - and they did have some criteria for malignancy (variable sizes, rare binucleated cells, etc.)

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Cytologic diagnosis: Sarcoma.  With follow-up histology we confirmed this bad-boy to be a chondrosarcoma.  Chondrosarcomas arise from chondrocytes, the cells responsible for building cartilage.  Chondrosarcomas are some the most gorgeous appearing tumors cytologically!  Mostly because of all the pink-magenta substance they produce.  Fortunately chrondrosarcomas in dogs rarely spread throughout the body, so surgical excision of the primary tumor is usually curative.  This patient had the tumor (and a whole section of his body wall!) removed and is currently disease free.

Draining cutaneous lesion from a 10 year-old, male-castrated, Domestic Medium Hair.  The patient is an indoor/outdoor cat that ‘disappears’ for days at a time from his house.  The owner noticed the cat limping after returning from a ‘disappearance’ and on close examination found a pus-draining wound on his left hindlimb.  The patient’s primary care veterinarian took some samples of the discharge and sent it our way.

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As you may expect, the discharge was simply loaded with inflammatory cells.  Most of these inflammatory cells were neutrophils with few really activated macrophages found (the big foamy cells in the top picture!)  Any time you see inflammation, you should start hunting for bacteria.  In one little cluster I thought I saw very thin, filament like bacteria (black arrows)…  

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…I know, you are probably calling BS, but I swear they are bacteria.  And using an acid fast stain (designed to highlight certain kinds of bacteria), you can see how many organisms there really are!  The bacteria are highlighted in red-pink in the bottom image - and they were EVERYWHERE!  They just did not stain well with our routine cytology stain.

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Cytologic diagnosis:  Marked pyogranulomatous inflammation with intralesional filamentous bacteria.  This type of inflammation - along with these kinds of bacteria - are often associated with plant foreign material.  Animals can get all kinds of plant material buried in their skin - I’ve pulled out thorns, grass-awns, whole branches, cactus spines, etc.  Prognosis is great with antibiotics and removal of the foreign material (presuming it’s there!)

Three skin masses present on a 15 year-old, female-spayed, Domestic Short Hair.  The kitty cat’s owner recently felt 3 small, firm masses on the patient’s left forelimb.  The masses were about 1cm apart and non-painful on manipulation.  Aspirates from all three lesions showed…

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Copious amounts of these round cells!  Most of these bad boys contain discrete, purple (or metachromatic!) granules.  Any idea what these cells are…..?  These are mast cells!  Making this a mast cell tumor, sometimes called a mastocytoma.  These cells will often ‘pop’ when cytology slides are made, releasing the granules into the background (see all the free granules in the bottom picture?)

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Cytologic diagnosis:  Mast cell tumor.  Feline mast cell tumors are typically low-grade in behavior - meaning they grow locally but rarely spread to other parts of the body.  In this case, the patient could be facing a more high grade tumor as she has multiple skin tumors simultaneously.  The presence of multiple cutaneous mast cell tumors in a cat is no bueno - many of these cats actually have disseminated disease.  In cats, disseminated mast cell disease will often shore up in the spleen.  No word yet on this patient’s next move, although I suspect these masses will be removed and a hunt will begin for internal tumors.  

Inappropriate Cell of the Week!!!!
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We found this big ugly in thoracic fluid from a dog with diffuse chest cancer (carcinomatosis to be exact).  Let me state this plainly…a cell like THIS should NEVER be found in the body normally.  Not ever!  This cancer cell is unholy on so many different levels…

Cervical mass in a 11 year-old, male-castrated, black Labrador Retriever.  For the past two weeks the patient has been intermittently coughing, especially after voraciously eating his  kibbles.  He is described as healthy otherwise.  On physical examination his primary care veterinarian palpated a very large, 10cm firm mass in his ventral neck.  We got the aspirate samples of the mass and found….

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…and found numerous apparently cohesive clusters of these mononuclear cells.  Their cohesive nature is typical of an epithelial population.  The cells look relatively bland - that is, they all appear very similar to their neighbor.  Such monomorphism suggests a more benign process…but we’ll come back to that interpretation!  Additionally, few clusters were associated with this brilliant magenta extracellular material - could be matrix, secretory product, or colloid.  What tumor type do think this is?!

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Cytologic diagnosis: Neuroendocrine epithelial tumor.  Based upon the mass location, this is consistent with a Thyroid tumor.  Although the population looks relatively benign cytologically, canine thyroid tumors are usually aggressive adenocarcinomas.  Conversely, kitty thyroid tumors are usually benign and equine tumors a 50-50 shot on benign versus malignant.  No word yet on what therapy the owner has elected to pursue - but the prognosis is sadly grave :-(

On an aside, other neuroendocrine origin tumors (like insulin secreting pancreatic tumors or some adrenal tumors) have a very similar cytologic appearance. 

Cutaneous mass on a 5 year-old, Nigerian Dwarf Goat doe.  The owner noticed a small mass growing on the patient’s flank over the past few weeks.  The mass appeared firm and non-painful on palpation.  However, the mass eventually begin leaking small amounts of pus - which prompted the owner to immediately contact her veterinarian!

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So we saw these bad boys on cytology!!!  Any guess what this organism is……..

Those little structures are yeast…and their big ‘halo’ capsule means these are cryptococcal yeast.  We like to term them yeasty beasties!  There were hundreds of these yeast structures throughout the needle aspirates we received - along with many inflammatory cells (like the big vacuolated macrophage in the top picture).  The patient’s lesion ended up being excised and submitted for histology.  The bottom image is the histology of the mass….and it makes a gorgeous mosaic of yeast, inflammatory cells, red cells, and fibrin!  Notice how different the Crypto yeast looks between cyto and histo?!

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Cytologic diagnosis:  Pyogranulomatous inflammation with intralesional cryptococcal yeast.  AKA Cryptococcosis.  This disease is caused by organisms from the genus Cryptococcus.  There are two main species of this yeast, C. neoformans and C. gattii.  C. gattii is considered much more a primary pathogen, while C. neoformans is typically an opportunistic pathogen.  In our area of the world, C. gattii dominates :-S  Cryptococcosis in goats is exceedingly rare, with most reported cases having either mammary or respiratory tissue involvement.  Either way, this organism makes GORGEOUS cytology images!

Aspirate of an intermandibular swelling from a 5 year-old, male-castrated, Domestic Shorthair.  The patient present for evaluation of acute onset respiratory distress.  According to the owner the cat was fine the day before, but in the morning was reluctant to eat and then appeared to have breathing difficulties by the afternoon.  On examination a very large swelling was found underneath the tongue and extending into soft tissue region between the mandibles. 

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Cytology revealed COPIOUS amounts of bacteria along with inflammatory cells.  Almost every type of bacteria under the sun was present…small rods, filamentous rods, cocci, coccobacilli, and (one of my favorites!) spirochetes.  The spirochetes are a bit hard to pick out initially - but once you see one (denoted by the arrow) your eyes will begin to pickout all of them in the background.  All the streaming blue debris is from ruptured neutrophils - there are a few intact neuts dead center in the top picture.

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Cytologic diagnosis: Marked, septic, suppurative cellulitis.  AKA an abscess.  Given the location, this abscess could have resulted from a bite wound or foreign body.  Many of the bacteria likely originated from the oral cavity.  In particular the mouth has many kinds of spirochete bacteria that can contribute to oral gingivitis and perioral abscesses.  In people, severe gingivitis associated with spirochete infection is termed Trench Mouth.  We see it in pigs too!

So very sorry for my protracted absence from the Tumblr community.  Life has been crazy lately…but things are finally settling down. So let the cytology awesomeness begin again!

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Lymph node aspirate from a 10 year-old, male-castrated, German Shepherd Dog.  The patient had a recent onset of lethargy and anorexia.  On examination the patient had significantly enlarged peripheral lymph nodes.  In addition, spleen and liver enlargement were suspected on abdominal palpation.  Aspirates of the lymph node were acquired and this is what we say…

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The samples were wall-to-wall lymphoblasts.  In a normal lymph node you should have 90%+ small mature lymphocytes…in this case I only found about a dozen on the entire slide.  Interestingly enough the lymphoblasts also contained these angular, white inclusions.  Any guess what these could be???  Based upon some special stains, we suspect they are accumulations of antibody!  Crazy to see them this angular though!

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Cytologic diagnosis: Lymphosarcoma.  We even went a little further with this case and found it is a B-lymphocyte tumor.  Which completely fits with the antibody inclusions.  Recall that normal B-cells have the potential to become plasma cells, which make the antibody that so preciously protect us from microbes!  We also found these nasty blasties in the spleen, liver, and circulating in blood.  Thankfully the patient has responded well to chemotherapy thus far.

Aspirate from an oral lesion from a 9 year-old, male-castrated Domestic Shorthair.  So no really pathology was evident in this sample….but it did show something super cool!!  Do you notice all those roly polies?!?!?!  Well of course they are not actual roly polies, but instead are stacks of an organism called Simonsiella.  This little bacteria is normal ‘flora’ of the mouth – we all have a TON of it – and likes to live in little colonies resembling our roly poly friends.  In rare cases, they are documented to exacerbate oral ulcers in dogs….in super rare cases…

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Also, I sincerely apologize for the recent gap in my posts!  I was away last week and SADLY will be away this coming week as well.  However, I will do my best to get some tasty cytos for you from a distance!

Lung tissue from a mature Barn Owl.  The history on this animal is pretty minimal: the bird was found dead one morning at someones property.  The fish and wildlife service was called, and upon examining the owl found no gross abnormalities (besides being dead!)  The animal was sent our way for a necropsy - the animal equivalent of an autopsy.  The owl’s lungs were found to be very dense on palpation….which is never a good things as they should full of air!  Specimens were collected for histologic evaluation…
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….and the lungs were found to be completely colonized by fungus!  Hence the firmness.  The above picture shows numerous blue-purple hyphae (easy to see on the bottom left) along with these very large, fruiting body structures!  The fruiting bodies look like the Starship Enterprise :-P These structures are actually termed conidiophores, which are comprised of conidia (the tiny dots).  Conidia are variants of spores.
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Diagnosis:  Aspergillosis (presumed).  Many avian species are susceptible to primary and secondary fungal infections….and one of their biggest nemeses are Aspergillus species.  The organism has been responsible for large die-offs of water fowl throughout the Pacific Northwest over the past decade….and was no doubt the cause of this owl’s death.