The cytopathology of musculoskeletal and neurologic disease Flashcards
Normal synovial fluid
- consistency, contents
- how to collect and sample
- cells
- Viscous, high mucopolysaccharide content
- Aspirate fluid slowly, prepare slides slowly!
> fluid is thick and slow moving
> just make one slide - Cell count <3x109/L, protein <30 g/L
Suppurative inflammation of joint
- most likely dx in small animals? large animals?
- Predominance of neutrophils = most likely immune- mediated polyarthritis in small animals
- Predominance of neutrophils - likely septic cause in large animals, even if the organism is not apparent
Non-suppurative inflammation of the joint
- when we see this?
- what do we see?
- Degenerative joint diseases manifest mostly with mild increases in mononuclear cells (lymphocytes & macrophages)
- Occasional osteoclasts if erosive joint disease
canine osteoarthritis - progression of synovial membrane, joint space, cartilage as joint degenerates
Normal:
- synovial membrane: mobile and flexible
- joint space: thick and elastic synovial fluid
- healthy cartilage
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Beginning of destruction:
- synovial membrane: mobile and flexible
- joint space: narrowing, thin synovial fluid
- thinning cartilage due to wear and tear and destructive enzymes
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More progressed osteoarthritis:
- synovial membrane: fibrosed and rigid
- joint space: narrowed, bone on bone, thin and watery synovial fluid
- loss of cartilage
infectious synovitis - is it always bacteria?
no it can also be fungal
what can we find in joint fluid in a case of gout?
uric acid crystals in joint fluid
Osteosarcoma
- who gets it?
- what bones?
- behaviour?
- dx? considerations?
- Tumor of large breed, middle-age dogs
> cometimes in young - Long bones, flat bones, mandible, maxilla, ribs…
- Especially: Metaphysis, distal radius & proximal humerus (“away from the elbow”)
- Mandibular OSA better prognosis?
- Different histologic subtypes – all behave similar = malignant
- Metastasis common
- Metastasis early and subclinical (= not radiographically detectable)
- Amenable to cytologic diagnosis, but need to select site for aspiration carefully
where to aspirate for in osteosarcoma
Aspirate from the center of the lesion!
Chondrosarcoma
- predilection sites
- breed
- behaviour
- more common on flat bones
- most common nasal cavity?
- Golden Retrievers predisposed?
- slow to metastasize > there is time to decide on next steps / tx
Unusual bone tumors:
a. Multilobular tumor of bone (osteochondrosarcoma)
* arise on the skull
* discrete masses with bony proliferation
* better prognosis than osteosarcoma
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b. Hemangiosarcoma, osteoma, fibrosarcoma, multiple cartilagenous exostosis
Soft tissue sarcomas
- older terms?
- why are they lumped together
Older terms:
* Hemangiopericytoma (vascular wall tumor)
* nerve sheath tumor
* fibrosarcoma
* synovial cell sarcoma
* liposarcoma
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Lumped together since have similar grading criteria and prognosis.
Most tumors of the musculo-skeletal system are amenable to cytologic diagnosis if care is taken to:
- to acquire a good sample, and
- to prepare good smears > one layer of cells, not clotted
Histiocytic diseases
- cell lineages from stem cell
bone marrow stem cell:
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1. blood monocyte > macrophage > Hemophagocytic histiocytic sarcoma
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2. Interstitial dendritic cell > Histiocytic sarcoma
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3. Langerhans cell (in the skin) > Histiocytoma
Cutaneous histiocytoma appearance, sugnalment, prognosis
- Small, non-haired lump
- Typically young dog
- 90% go away by themselves, if not we can cut if off
Histiocytic sarcoma
- sites?
- behaviour?
- typically around the stifle, also other sites
- aggressive neoplasm
- very inflammatory
Histiocytic diseases
* Malignant histiocytic neoplasms sites
* hallmarks of these cancers
* hematology
- Malignant histiocytic neoplasms can occur at any site, although the spleen, bone marrow, lung and stifle are predisposed.
- The hallmarks of these malignant cancers are multinucleation and variable inflammatory infiltrates.
- Anemia +/- thrombocytopenia are invariably present if the tumor involves the spleen or bone marrow, and arises from phagocytic macrophages.
Breed predisposition to Histiocytic Sarcoma
- flat coated retriever, burnese mountain dog
Neoplastic diseases of the musculo-skeletal system - cats
- what are common and uncommon? unique?
- Vaccine-site associated sarcomas are the most common tumor of the musculo-skeletal system
- Osteosarcomas are uncommon
- Squamous cell carcinomas that invade bone and/or soft tissue are common
- Primary lung carcinoma with digital metastasis – unique in the cat
- Cutaneous lymphoma may be more common than in dogs
Musculoskeletal tumors in large animals
- fibroma - space occupying
- sarcoid - papilloma associated, surgery alone will not take them off (radiate)
- Keloid - exuberant response to injury
Cerebrospinal fluid - normal
- cellularity
- protein
- sampling method
- when to take? use?
- very low cellularity (<0.003x109/L)
- very low protein content (< 0.3 g/L or < 0.8 g/L in horses)
- need anesthesia to obtain in small animals
> flows from head to tail, take just downstream, as close to lesion as possible - need to process rapidly since cells unstable
- Therefore: expensive sample to obtain and requires special processing
<><><><> - in health: predominance of mononuclear cells
- mostly lymphocytes +/- monocytes and macrophages
- essential component for evaluation of suspect inflammatory diseases of the CNS
- changes in CSF are common, but rarely diagnostic of a specific disease process
Lymphocytic inflammation of CSF
- causes
- viral infections (etiology?)
- herpesvirus, distemper, feline infectious peritonitis, feline immunodeficiency virus
- “Shaker” disease of small, often white, dogs
- Pug encephalitis
Suppurative inflammation of CSF causes
- bacterial meningitis
- steroid-responsive meningitis/arteritis
- Ehrlichia spp. or Anaplasma spp. infections
- protozoal infections – Toxoplasma, Neospora, etc.
- CNS neoplasia
- Remember: Bacteria are rarely observed in suppurative CSF samples!
Mixed inflammation of CSF - when we see it
- increased cell count, different cell types
- typical for “meningoencephalitis of unknown origin” (MUO); old term “granulomatous meningo- encephalitis” (GME)
- may be seen in protozoal and listerial meningitis
Eosinophilic inflammation - when we see it?
- most commonly idiopathic, Rottweilers appear predisposed
- may be associated with parasitic infections or unusual responses to protozoal infections
CNS neoplasia
- dx
- use of cytology, CSF
- Diagnosing and treating CNS neoplasia requires advanced veterinary facilities and skills.
- Most CNS neoplasms are diagnosed by imaging techniques.
- Cytology of tumors is a useful adjunct in the diagnosis of CNS neoplasia due to the rapidity of diagnosis.
- CSF analysis is rarely useful for definitive diagnosis of CNS neoplasia.
Brain tumors:
- what types and who gets them
- growth pattern
- Glial cell & pituitary tumors – more common in brachycephalic dogs?
- Meningiomas – most common overall, more common in dolichocephalic dogs?
- Often “benign” growth pattern … but bad location.
Spinal cord tumors:
- what types, and who gets them
- Dogs: meningioma, hemangiosarcoma
- Cats: lymphoma, lymphoma, lymphoma …
CNS neoplasia
- CSF abnormalities
- Typical CSF abnormalities with CNS neoplasia are increased protein concentration and no increase or only a very slight increase in the total cell count and proportion of neutrophils.
> disrupted blood brain barrier > protein leaking in there
CNS neoplasia
- what type of tumors can usually be diagnosed by cytology
- Tumors affecting vertebrae and causing neurological signs due to impingement or necrosis on the spinal cord can usually be readily diagnosed by cytology.
Vertebral neoplasia
- Vertebral lysis – rule outs?
Osteosarcoma
Histiocytic sarcoma
Multiple myeloma
Metastatic carcinoma
