L14 Neoplastic diseases Flashcards
Rhabdomyoma
Cardiac rhabdomyoma (incidental)
• Laryngeal rhabdomyoma
Benign tumors of striated muscle
• Common in pigs and guinea pigs
• Left ventricle usually
• Smooth nodules embedded within myocardium
• Common in dogs, 2-10 years old
• Nodular mass protruding into laryngeal lumen
• Dyspnea, stridor
Rhabdomyosarcoma
• Often occurs in sites with little to no skeletal
muscle
• Juveniles more commonly affected
• Aggressive, rapid growth
• Locally invasive, often metastasize
• Embryonal rhabdomyosarcoma
• Head or neck or oral cavity
• More common in dogs
• Pale streaks to nodular masses
• Botryoid variant
• Most often in trigone areas of urinary bladder
• Large breed female dogs
• Grapelike masses in trigone of bladder
Chondroma
• Rare, benign tumor of cartilage
• Can arise within bone (medullary cavity) or outside of bone
• Involve flat bones and ribs more commonly
• Dogs, cats, cattle
• Firm to hard, smooth, nodular masses
• Often have fibrous capsule
• Discrete lesions, slow growing
Osteochondroma
• Benign, cartilage capped mass of periosteal origin
• Arise next to growth plates
• Occur in juvenile animals
• Generally do not metastasize
• Dogs and horses
• Tend to be bilaterally symmetrical
• Can be present at birth
• Neoplastic bone arises from endochondral
ossification sites
• Long bones, ribs
• Can interfere with ligaments and tendons
• Stops growing when bone stops growing
• Dogs: often poor prognosis due to malignant
transformation
Chondrosarcoma
Mesenchymal tumor producing cartilage but not
osteoid
• Arise most commonly in flat bones
• Dogs: nasal bones, ribs, pelvis
• Sheep: ribs, sternum
• Usually middle-aged to older dogs
• Boxers, GSD, Goldens
• Local invasion common, metastasis to lung is slow
• Firm or hard mass with multiple small areas of
transluscent blue, white, or pink tissue
• Areas of necrosis and hemorrhage within tumor
• Cytology: Amorphous lakes of homogeneous magenta
pink matrix (cartilage)
• Cannot distinguish from osteosarcoma on
rads
Multilobular tumor of bone
Nodular tumor of the flat bones of the canine
skull
• Typically seen in younger dogs
• Locally aggressive, slow growing
• Unknown pathogenesis, arises from suture lines
• Hard, immovable mass involving skull bones
• Very hard, smoothly contoured, nodular mass with
discrete border
• Zygomatic arch, occipital and parietal bones, maxilla,
mandible, and tympanic bulla
• Clinical signs due to local invasion and compression • Metastasis to the lungs late in disease
Very hard, smoothly contoured, nodular mass with
discrete border
Osteosarcoma
Most common canine/feline primary appendicular
neoplasm
• Usually arises from metaphyseal region of long bones
• Usually large/giant breeds of dogs
• Cell of origin uncertain
• Makes osteoid
• Rapidly progressive and aggressive
• Metastasizes frequently and early to lungs
• ”Away from elbow; toward the knee” • Mass around and encompassing bone
• Can see pathologic fracture
• Rads:
• RARELY crosses joints!
• Lytic, productive, mixed patterns
• Clin Path: elevated ALP (bone isozyme)
• Cannot distinguish from chondrosarcoma on rads
Chordoma
Most common musculoskeletal tumor
of ferrets
• Thought to arise from intraosseous fetal
notochord remnants
• Slow growing, locally aggressive
• Composed of bone, cartilage, physaliferous
cells
• Can occur anywhere on axial skeleton
• Rarely metastasize
• Multilobulated, soft, gelatinous gray mass
• Most common on tip of tail, cervical
vertebrae
Tumor Joints
Synovial Myxoma
Second most common neoplasm in joints
of dogs
• Benign neoplasms
• Large breed, middle-aged
both sides of joint
• Gelatinous nodules associated with joints
• Pockets of viscous fluid
• Dobermans and Labs
• Stifle and digit most common locations
• Usually occurs in single joint
• Generally benign, can cause bony lysis on
tumors of the joint
Histiocytic sarcoma
Most common tumor in joints of
dogs
• Bernese Mtn. dogs, Rotties, Goldens,
• Localized form of HS
• Tumor of interstitial dendritic cells
• Stifle and elbow most commonly
affected
• History of CCL rupture is associated with
this entity
• Can metastasize
• Multiple nodules beneath synovial lining
• Can progress outside of joint
tumors of the joint
synovial chondromastosis
Non-neoplastic condition of synovium
• Primary (rare, spontaneous)
• Giant breed dogs, usually males
• Shoulder most commonly affected
• Secondary (associated with DJD)
• Often see evidence of DJD in surrounding
bone
• Likely a reactive metaplasia of synovium to
cartilage
• Multifocal, firm, pearl-like nodules
• Can detach and free-float
• Can ossify to bone à osteochrondromatosis
Radiographic changes
aggressive bone lesions
1.Periosteal reaction
a. Pattern
2. Lysis/destruction of bone
a. Pattern of lysis
b. Cortical bone destruction
3. Zone of transition
a. Well-demarcated vs fuzzy edges
Periosteal reaction patterns
bony lysis patterns
zone of transition
bone diseases
