Neoplasia (Malignancy, Effects & Spread) Flashcards
Why does a mesothelioma arising in, for example, the pericardial cavity spread only within that cavity?
When mesothelioma arises on a serosal surface (i.e., pericardium, peritoneum or pleura) it easily spreads transcoelomically within the cavity, but cannot cross the anatomic barriers of the fibrous pericardium or the diaphragm.
A poorly differentiated neoplasm has a better prognosis than a well-differentiated neoplasm. True or false?
FALSE
Malignant neoplasms are typically poorly demarcated. True or false?
TRUE
What is the meaning of the term paraneoplastic effect?
Paraneoplastic effects are indirect and remote effects that are caused by tumor cell products rather than by the primary tumor or its metastases
Compare the cellular differentiation of a benign fatty tumor (lipoma) with that of a malignant fatty tumor (liposarcoma)
The benign lipoma is composed of mature fat cells indistinguishable from normal cells. The liposarcoma consists of poorly differentiated cells, many of which do not have the morphologic features characteristic of adipocytes.
Compare the number and appearance of mitotic figures in a “typical” benign and “typical” malignant neoplasm
Benign: mitotic figures are relatively scarce and of normal appearance; Malignant: mitotic figures are relatively numerous and may have a bizarre appearance
Who grades neoplasms and why?
Grading is carried out by veterinary pathologists. The assumption is that grading provides some predictive ability about future behavior of the tumor. This is not universally true, however, and tumor staging (by a veterinary oncologist) is often more useful.
Explain the key differences in the extent and type of local invasion by a “typical” benign and “typical” malignant neoplasm
Benign: expands and compresses, but does not invade or infiltrate adjacent normal tissue; Malignant: infiltrates and invades adjacent normal tissue
Leukemia may be classified as either ___(a)____ or ___(b)___ based on the degree of differentiation of the neoplastic cells and their biologic behavior. What are terms (a) and (b)?
(a) Acute; (b) Chronic
Name three common paraneoplastic effects seen in veterinary medicine.
- Cachexia
- Hypercalcemia of malignancy
- Hypertrophic osteopathy
A well-differentiated neoplasm has a better prognosis than a poorly differentiated neoplasm. True or false?
TRUE
Mesothelioma is a malignant neoplasm of mesothelial cells. Mesothelial cells, along with endothelial and synovial cells, are derived from which layer of the trilaminar embryonic disc?
Mesoderm. See your Neoplasia 1 lecture for an explanation.
You excise a subcutaneous neoplasm from a dog and submit it to a veterinary pathologist. The pathologist may be able to [choose one]: (a) grade the neoplasm; (b) stage the neoplasm.
(a) Grade
What are the four most important characteristics of a neoplasm that help determine if it is benign or malignant?
- Presence or absence of metastasis
- Growth rate and number & appearance of mitotic figures
- Degree of local invasion, and whether it is expansile or infiltrative
- Degree of differentiation of neoplastic cells
You radiograph a dog and notice severe symmetrical periosteal proliferation in all distal long bones. What is the name of this disease?
Hypertrophic osteopathy. This is a paraneoplastic effect of space-occupying thoracic masses that results in periosteal proliferation in the distal long bones. The mechanism is unknown.
Who stages neoplasms and why?
Staging is carried out by veterinary oncologists. It gives an indication of the extent of tumor growth and spread, which guides the clinician in developing a therapeutic plan and offering an estimate of prognosis to the client.
Which type of neoplasm - benign or malignant - loses cellular differentiation?
Malignant
What are three reasons why recognition of paraneoplastic effects in a patient is important?
- Paraneoplastic syndromes may appear early in the course of tumor development and may be associated with specific tumor types, thus recognition of these syndromes can facilitate early tumor diagnosis
- Treatment of the metabolic abnormalities associated with paraneoplastic syndromes and antitumor therapy may be required to assure effective cancer management
- The severity of paraneoplastic abnormalities reflects the tumor burden; thus monitoring such abnormalities may be useful in determining tumor response to therapy and identifying tumor recurrence or spread.
Name a neoplasm that commonly spreads transcoelomically.
Mesothelioma (and ovarian adenocarcinoma)
What, in terms of tissue lost, is the key difference between weight due to starvation and weight loss due to cancer cachexia?
In cancer cachexia, both muscle and fat are lost, whereas in simple starvation fat is lost preferentially. [Also, in starvation, there is a compensatory decrease in basal metabolic rate that is not seen in cancer cachexia.]
You radiograph a dog and notice severe symmetrical periosteal proliferation in all distal long bones. What part of this dog should you radiograph next, and why?
The thorax. This dog has hypertrophic osteopathy, a paraneoplastic effect of space-occupying thoracic masses that results in periosteal proliferation in the distal long bones. The mechanism is unknown.
Aside from direct invasion, what are three methods by which malignant neoplasms spread?
- Transcoelomically
- Via lymphatic vessels
- Via blood vessels
Neoplasms whose cells are anaplastic are well-differentiated. True or false?
FALSE
Neoplasms whose cells are anaplastic are poorly differentiated. True or false?
TRUE
You refer a dog with a subcutaneous neoplasm to a veterinary oncologist. The oncologist may be able to [choose one]: (a) grade the neoplasm; (b) stage the neoplasm.
(b) Stage
What is the umbrella term referring to malignant hematopoietic neoplasms that originate in the bone marrow and typically have significant numbers of neoplastic cells in the blood?
Leukemia
Malignant neoplasms are typically well-demarcated. True or false?
FALSE
Benign neoplasms, if poorly differentiated, may metastasize. True or false?
False. Benign neoplasms do not, by definition, metastasize
Benign neoplasms are typically poorly circumscribed. True or false?
FALSE
Which of the following is frequently elevated in the blood as a paraneoplastic effect? (a) Bicarbonate; (b) Calcium; (c) Phosphorus; (d) Potassium; (e) Sodium
(b) Calcium; this is hypercalcemia of malignancy
One staging scheme used by veterinary oncologists is the ‘TNM’ scheme. What does TNM stand for?
Tumor, Node, Metastasis. The TNM scheme is based on the size of the primary tumor (T), degree of lymph node involvement (N), and extent of metastasis (M).
Leukemia may be classified as either ___(a)____ or ___(b)___ based on the cell of origin. What are terms (a) and (b)?
(a) Lymphoid; (b) Myeloid
As a general rule, squamous cell carcinoma arising in the head (eye, mouth, pinna etc.) will metastasize to the [choose one]: (a) bones; (b) brain; (c) liver; (d) lungs; (e) regional lymph nodes
(e) Regional lymph nodes
Benign neoplasms are typically non-infiltrative. True or false?
TRUE
By definition, metastasis means a neoplasm is _______.
Malignant. Benign neoplasms do not metastasize
What are mitotic figures, and what does their presence indicate?
Mitotic figures are chromosomes arranged for cell division. Their presence indicates that a cell is dividing (undergoing mitosis)
Neoplastic cells that bear no resemblance to their cell of origin and have a bizarre appearance are termed _______
Anaplastic
In which of the following canine neoplasms is hypercalcemia commonly seen? (a) Adenocarcinoma of the apocrine glands of the anal sac; (b) Lymphoma; (c) Oral malignant melanoma; (d) Oral squamous cell carcinoma (e) Transitional cell carcinoma
BOTH (a) adenocarcinoma of the apocrine glands of the anal sac and (b) lymphoma
What is hypertrophic osteopathy?
A paraneoplastic effect of space-occupying thoracic masses that results in periosteal proliferation in the distal long bones. The mechanism is unknown.
What is the term for indirect and remote effects of a neoplasm that are caused by tumor cell products rather than by the primary tumor or its metastases?
Paraneoplastic effects
Hypercalcemia of malignancy develops in roughly 90% of cases of which type of neoplasm in dogs?
Adenocarcinoma of the apocrine glands of the anal sac [“Anal gland carcinoma” is completely wrong and you should never say this.]
What is the meaning of the term leukemia?
Leukemia is the umbrella term referring to malignant hematopoietic neoplasms that originate in the bone marrow and typically have significant numbers of neoplastic cells in the blood
