Cancer Testing & Paraneoplastic Syndromes

Question 1

What is the goal in using cytology as a diagnostic for cancer? What are 2 pros and a con?

Answer 1

obtain cells from an abnormal area (mass, fluid, enlarged organ) for evaluation to determine etiology

• PROS: easy/inexpensive, usually doesn’t require sedation
• CON: less overall detail compared to histopath (cells vs. tissue)

Question 2

What 3 things can cytology determine in a cancer diagnosis?

Answer 2

1. differentiate cancer vs. non-cancer
2. categorize type of cancer (sarcoma, carcinoma, round cell)
3. diagnose specific cancers (MCT, lymphoma)

Question 3

What are the 3 major methods of performing cytology?

Answer 3

1. FNA - masses, LNs, ultrasound-guided for liver and spleen
2. fluid sample - pleural, peritoneal, or pericardial fluid
3. touch prep - ulcerated masses (inflammatory cells seen), biopsy samples

Question 4

What is the goal in performing a biopsy for a cancer diagnosis? What equipment is commonly used? How does it compare to cytology?

Answer 4

obtain a representative tissue sample from a mass or enlarged organ

incisional/excisional may require sedation or GA; trucut or punch may require a local block

$$$, more information given

Question 5

What 4 pieces of information can be gained when performing a biopsy?

Answer 5

1. diagnoses specific tumor type
2. tumor grade
3. assess for angiolymphatic invasion
4. assess surgical margins if a mass was removed

Question 6

What is immunohistochemistry?

Answer 6

staining tests for unique cell surface markers on biopsy samples if histopathology is inconclusive

Question 7

What cell surface markers are used in IHC for epithelial cells, mesenchymal cells, T cells, and B cells?

Answer 7

cytokeratin (carcinoma0

vimentin (sarcoma)

CD3

CD20

Question 8

What is a PARR assay? What 2 purposes does it have?

Answer 8

PCR test that looks for clonality seen in cancerous lymphocytes

1. diagnose lymphoma when cytology is inconclusive
2. phenotypes T vs B cells

Question 9

How is flow cytometry used in cancer testing? What purpose does it serve?

Answer 9

cells in a sample are individually evaluated by a laser and the machine uses scatter to determine type of cell and its size (can check for surface markers, too)

phenotypes T vs B cells (slightly better than PARR)

Question 10

What is cancer staging? How does it compare to grading?

Answer 10

performing diagnostics to determine the extent of neoplastic disease within the patient

based on histopathology biopsies —> cellular properties of the cancer itself

Question 11

What is the purpose of continuously performing cancer testing?

Answer 11

• gives a prognosis - with metastasis and malignancy, there is commonly nothing to gain when removing the primary tumor
• determine/change treatment options or plans
• establishes a baseline
• tests for concurrent disease

Question 12

How are CBC, chem, and UA commonly affected by cancer?

Answer 12

rarely see evidence (maybe some inflammation)

Question 13

What specific signs are seen on CBC/chem/UA in cases of lymphoma/leukemia and osteosarcoma?

Answer 13

neoplastic lymphocytes on CBC, hypercalcemia (worse prognosis!)

elevated ALP indicates a worse prognosis

Question 14

What are the 2 purposes of performing thoracic radiographs for cancer testing?

Answer 14

1. “met check” - RL, LL, VD views to observe small or solitary nodules that likely metastasized to the lungs (diffuse will be seen on any view)
2. determine tumor types - lung metastasis is common, round cells tumors may only require 2 views, not as necessary for MCTs

Question 15

What neoplasias can be seen with abdominal ultrasounds?

Answer 15

• systemic cancer with abdominal visceral involvement - lymphoma, histiocytic sarcoma
• metastasis cancer from other intra-abdominal organs - splenic HSA, TCC, intestinal tumors, pancreatic tumors, liver tumors

Question 16

What are 2 purposes of CT scan for cancer testing? How does it compare to other diagnostics?

Answer 16

1. observing smaller masses better - pulmonary metastasis, abdominal visceral masses
2. evaluate extent of deep tumors - nasal tumors, invasive skin/SQ masses

requires anesthesia and is expensive

Question 17

What are paraneoplastic syndomes?

Answer 17

changes caused by the presence of cancer, not the tumor itself —> remote effect of neoplastic disease

Question 18

What are 3 possible etiologies of hypercalcemia of malignancy?

Answer 18

1. PTHrp secreted from tumor cells, which stimulates osteoclastic resorption of bone by binding to PTH receptors (lymphoma!)
2. excessive secretion of PTH from parathyroid tumors
3. osteolysis caused by tumor cell invasion of bone

Question 19

What is the most common sign associated with hypercalcemia of malignancy? What other signs may be seen?

Answer 19

extreme PU/PD - calcium inhibits action of ADH in renal collecting ducts —> hyposthenuric urine!

• vomiting, anorexia, weakness, depression
• constipation
• hypertension
• bradycardia
• renal/cardiac calcification
• stupor, coma, death

Question 20

What are the 5 most common tumors that cause hypercalcemia of malignancy? What are some other possible causes?

Answer 20

1. T cell lymphoma
2. anal sac adenocarcinoma (rectal exam important!)
3. thymoma
4. multiple myeloma
5. parathyroid adenoma/adenocarcinoma

mammary carcinoma, osteosarcoma, bronchogenic carcinoma (cats), SCC (cats)

Question 21

What are 6 options for treating hypercalcemia of malignancy?

Answer 21

1. treat underlying disease - remove source of hormone production (likely tumor)
2. bisphosphonates (Zoledronate, Pamidronate) - binds to hydroxyapatite receptors in bone and inhibits osteoclastic bone resorption
3. glucocorticoids (Prednisone) - treats cancer directly (lymphoma), decreases intestinal calcium absorption, calciuresis
4. 0.9% NaCl at 2-3x maintenance rate - calicuresis
5. Furosemide - inhibits calcium reabsorption at the thick loop of the ascending LoH
6. calcitonin - inhibits osteoclastic activity in bone, calciuresis

Question 22

How is hyperglobulinemia diagnosed? What causes it?

Answer 22

submit serum protein electrophoresis —> most likely monoclonal gammopathy (Ehrlichia can also cause this!)

excessive globulin production from cancer cells

Question 23

What clinical signs are associated with hyperglobulinemia?

Answer 23

usually no signs other than hyperglobulinemia on bloodwork

however, hyperviscosity syndrome can happen, which causes:

• depression
• hypertension
• blindness (retinal detachment)
• neurological signs
• coagulopathy, epistaxis

Question 24

What are the 4 most common tumors that cause hyperglobulinemia? What tumors is it not seen in?

Answer 24

1. multiple myeloma
2. extramedullary plasma cell tumors
3. lymphoma (cats > dogs)
4. chronic lymphocytic leukemia (less common)

cutaneous plasma cell tumors

Question 25

What 2 treatments are recommended for hyperglobulinemia?

Answer 25

1. treat underlying disease - Prednisone, Melphalan (multiple myeloma)
2. plasmapheresis - remove some of the patient’s plasma and replace with donor plasma (only if hyperviscosity is seen)

Question 26

What cancer can cause GI ulceration? How?

Answer 26

MCTs

histamine release from tumor cells (large masses, metastatic disease)

Question 27

What cancer can cause erythrocytosis? How?

Answer 27

primary renal tumors

secrete erythropoietin from tumor cells

Question 28

What cancers can cause hypoglycemia? How?

Answer 28

insulinomas and leimyosarcomas

secrete excessive insulin or insulin-like factors from tumor cells

Question 29

What is hypertrophic osteopathy? What causes it?

Answer 29

thick, painful periosteal new bone formation on distal extremities

thoracic, renal, bladder tumors, granulomas/abscesses —> possibily causes reduced periosteal vascularity