Pathology: Skin Neoplastic + Non-Neoplastic Tumors
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What is the primary concern for clients regarding skin masses on their pets?

  • They are mostly benign.
  • They can lead to skin metastases.
  • They are commonly caused by infections.
  • They may require expensive treatments. (correct)
  • Neoplasms from other body parts frequently develop skin metastases.

    False

    What is the most valuable initial diagnostic test when investigating a skin tumor?

    cytology

    The advantages of cytology include its low cost and short time required to obtain results. Cytology samples are stained using a __________ stain.

    <p>diff-quik</p> Signup and view all the answers

    Match the following terms related to skin tumors with their definitions:

    <p>Cytology = A diagnostic method for evaluating tumors Fine needle aspiration = A technique to obtain a sample from a tumor Excision = Surgical removal of a tumor Chemotherapy = Treatment using drugs to eliminate cancer cells</p> Signup and view all the answers

    Which of the following is NOT a potential treatment plan for skin tumors?

    <p>Immunotherapy</p> Signup and view all the answers

    It takes more than 10 minutes to provide a diagnosis from cytology if the clinician interprets the slides themselves.

    <p>False</p> Signup and view all the answers

    What skill is valuable for a companion animal clinician in relation to skin tumors?

    <p>Diagnosing by cytology</p> Signup and view all the answers

    What is the most common canine skin tumor?

    <p>Histiocytoma</p> Signup and view all the answers

    Lipomas are a malignant form of skin tumor.

    <p>False</p> Signup and view all the answers

    What triggers the dystrophic calcification seen in Calcinosis circumscripta?

    <p>Trauma</p> Signup and view all the answers

    Canine cutaneous histiocytomas typically resolve in _____ weeks.

    <p>2-4</p> Signup and view all the answers

    Match the following dog breeds with their associated conditions:

    <p>Burnese Mountain Dog = Systemic Histiocytosis German Shepherd = Calcinosis circumscripta Rottweiler = Systemic Histiocytosis Young dogs = Histiocytoma</p> Signup and view all the answers

    What is the typical appearance of a lipoma upon palpation?

    <p>Soft and movable</p> Signup and view all the answers

    Systemic histiocytosis is a benign condition found in dogs.

    <p>False</p> Signup and view all the answers

    What type of cells are primarily involved in canine cutaneous histiocytomas?

    <p>Histiocytes</p> Signup and view all the answers

    Hemangiomas are commonly located on the _____ abdomen and medial thighs.

    <p>ventral</p> Signup and view all the answers

    Match the following tumors with their descriptions:

    <p>Histiocytoma = Rapidly growing, usually resolves in weeks Lipoma = Soft, mobile fatty mass Hemangioma = Dark purple mass, solar induced Calcinosis circumscripta = Nodular mass over bony prominences</p> Signup and view all the answers

    Which tumor requires histological examination for differential diagnosis?

    <p>Hemangioma</p> Signup and view all the answers

    Histiocytomas can be confused with systemic histiocytosis because they both involve histiocytes.

    <p>True</p> Signup and view all the answers

    What is a characteristic feature of the cytology of a lipoma?

    <p>Fat globules</p> Signup and view all the answers

    An infiltrative lipoma can be challenging to diagnose as it infiltrates through _____ muscle.

    <p>skeletal</p> Signup and view all the answers

    Which tumor type should be removed immediately according to its urgency?

    <p>Hemangiopericytoma</p> Signup and view all the answers

    Cytology is always sufficient for a definitive diagnosis of all tumor types.

    <p>False</p> Signup and view all the answers

    What is the most common cutaneous neoplasm with malignant potential in dogs?

    <p>Mast cell tumors</p> Signup and view all the answers

    Histiocytoma, lipoma, follicular cyst, sebaceous hyperplasia, and basal cell tumor are all examples of __________ in dogs.

    <p>benign skin tumors</p> Signup and view all the answers

    Match the following tumor types with their characteristics:

    <p>Sebaceous gland hyperplasia = Often appears wart-like and can be multifocal Follicular cyst = Develops from malformed hair follicles Nevus = Increased quantities of normal collagen Mast cell tumor = Common neoplasm with malignant potential in dogs</p> Signup and view all the answers

    Which of the following tumors can resolve spontaneously?

    <p>Inflammatory tumors</p> Signup and view all the answers

    Histology is more expensive than cytology.

    <p>True</p> Signup and view all the answers

    What is the main disadvantage of using cytology over histology?

    <p>Cytology may not definitively diagnose all tumor types.</p> Signup and view all the answers

    The __________ are often located on the eyelids and are common in older dogs.

    <p>sebaceous gland hyperplasia</p> Signup and view all the answers

    Match the following tumor types with their most common animal group:

    <p>Histiocytoma = Dogs Squamous cell carcinoma = Cats Follicular cysts = Dogs and Cats Basal cell tumors = Cats</p> Signup and view all the answers

    Which animal breed is mentioned as being commonly affected by sebaceous gland hyperplasia?

    <p>Beagles</p> Signup and view all the answers

    Mast cell tumors are the 5th most common canine skin tumor.

    <p>False</p> Signup and view all the answers

    What type of tumors are inflammatory tumors and what can cause them?

    <p>Inflammatory tumors can be caused by bacteria, fungi, viruses, or trauma.</p> Signup and view all the answers

    Aspiration of a follicular cyst reveals __________ material.

    <p>cloudy grey/brown</p> Signup and view all the answers

    What is a critical differentiator between sebaceous adenomas and sebaceous gland hyperplasia?

    <p>Size of the tumor mass</p> Signup and view all the answers

    What percentage of all canine skin neoplasms do benign sebaceous and apocrine gland tumors constitute?

    <p>10%</p> Signup and view all the answers

    Sebaceous gland epitheliomas are more common than sebaceous gland adenomas.

    <p>False</p> Signup and view all the answers

    Which type of benign neoplasm is characterized by large, foamy looking cells?

    <p>Sebaceous gland adenomas</p> Signup and view all the answers

    Complete excision is __________ for benign sebaceous and apocrine gland tumors.

    <p>curative</p> Signup and view all the answers

    Where are sebaceous gland adenomas most commonly found?

    <p>Eyelids, limbs, and trunk</p> Signup and view all the answers

    Squamous cell carcinoma is the most common malignant epithelial neoplasm in dogs.

    <p>True</p> Signup and view all the answers

    What is a characteristic feature of squamous cell carcinoma cells?

    <p>Large, angular, keratinized cells with retained nuclei</p> Signup and view all the answers

    Hepatoid gland adenomas are derived from modified __________ glands surrounding the rectum.

    <p>sebaceous</p> Signup and view all the answers

    What type of neoplasm is often confused with apocrine gland adenocarcinomas?

    <p>Hepatoid gland adenomas</p> Signup and view all the answers

    Castration of a dog may lead to regression of hepatocellular adenomas.

    <p>True</p> Signup and view all the answers

    What are the three subtypes of follicular neoplasms?

    <p>Trichoepithelioma, pilomatricoma, and intracutaneous cornifying epithelioma.</p> Signup and view all the answers

    Sebaceous gland adenomas that develop on the eyelids are also referred to as __________ gland adenomas.

    <p>Meibomian</p> Signup and view all the answers

    Match the following types of tumors with their description:

    <p>Sebaceous gland adenoma = Well-differentiated sebaceous cells Basal cell tumor = Derived from follicular basal cells Squamous cell carcinoma = Most common malignant epithelial neoplasm Hepatoid gland adenoma = Resembles hepatocytes</p> Signup and view all the answers

    Which type of tumor is known for being highly invasive and quick to metastasize?

    <p>Apocrine gland adenocarcinoma of anal sac origin</p> Signup and view all the answers

    What is suggested about the metastatic lesions in grey horses with lesions?

    <p>They represent a storage disease.</p> Signup and view all the answers

    Equine sarcoids tend to metastasize and are easily excised.

    <p>False</p> Signup and view all the answers

    What common cause is linked to cutaneous hemangiosarcomas in dogs?

    <p>Sunlight exposure</p> Signup and view all the answers

    The most common skin tumor of horses is called ________.

    <p>equine sarcoid</p> Signup and view all the answers

    Which type of cells are often revealed through cytology of equine sarcoids?

    <p>Spindle-shaped cells</p> Signup and view all the answers

    Dogs with cutaneous hemangiosarcomas typically do not develop multiple neoplasms.

    <p>False</p> Signup and view all the answers

    What virus is currently thought to be associated with the development of equine sarcoids?

    <p>Bovine papillomavirus (BPV)</p> Signup and view all the answers

    Match the following tumors with their characteristics:

    <p>Grey horse lesions = Do not typically cause clinical signs Cutaneous hemangiosarcoma = Induced by sunlight exposure Equine sarcoid = Caused by bovine papillomavirus Canine hemangiosarcoma = Usually metastasizes late in clinical course</p> Signup and view all the answers

    What types of neoplasms can develop on the external skin of the anus?

    <p>Hepatoid gland adenomas</p> Signup and view all the answers

    Apocrine gland adenocarcinomas are benign and do not metastasize.

    <p>False</p> Signup and view all the answers

    What is the primary systemic effect of hepatoid gland adenomas?

    <p>There are no systemic effects.</p> Signup and view all the answers

    Canine mammary neoplasms often consist of glandular and ductular structures lined by __________ cells.

    <p>anaplastic</p> Signup and view all the answers

    Match the following tumor types with their descriptions:

    <p>Hepatoid gland adenomas = Benign, testosterone-responsive Apocrine gland adenocarcinomas = Infiltrative and metastatic Mammary gland tumors in dogs = 50-80% benign Feline mammary adenocarcinomas = Rapidly metastasizes</p> Signup and view all the answers

    What is one of the benefits of early spaying in dogs?

    <p>Reduces the risk of mammary neoplasia</p> Signup and view all the answers

    Most canine mast cell tumors are associated with a grave prognosis.

    <p>False</p> Signup and view all the answers

    What is the easiest feature to recognize cytologically in mast cell tumors?

    <p>Presence of dark purple granules</p> Signup and view all the answers

    Cytology tends to be a poor predictor of the behavior of __________ tumors.

    <p>mast cell</p> Signup and view all the answers

    What is the most critical prognostic factor in feline mammary gland neoplasia?

    <p>Size of the neoplasm</p> Signup and view all the answers

    Castration prevents the development of testicular tumors in dogs.

    <p>True</p> Signup and view all the answers

    Which dog breeds are predisposed to mast cell tumors?

    <p>Labradors, Boxers, Shar Peis, Boston Terriers, Pugs</p> Signup and view all the answers

    Feline mammary adenocarcinomas often metastasize via __________.

    <p>lymphatics</p> Signup and view all the answers

    What percentage of mammary neoplasms in dogs are considered benign?

    <p>50-80%</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Cytology = Study of cells Histology = Study of tissues Benign = Non-cancerous Malignant = Cancerous</p> Signup and view all the answers

    What is the nature of feline cutaneous mast cell tumors (MCTs)?

    <p>Benign neoplasms that do not metastasize</p> Signup and view all the answers

    MCTs that develop in the gastrointestinal tract of cats are benign.

    <p>False</p> Signup and view all the answers

    What is the common treatment method for feline cutaneous MCTs?

    <p>Excision</p> Signup and view all the answers

    Equine MCTs are more likely to be __________ than neoplastic.

    <p>hyperplastic</p> Signup and view all the answers

    Match the tumor type to its primary characteristic:

    <p>Feline cutaneous MCTs = Almost invariably benign Equine MCTs = More likely hyperplastic Plasmacytomas in cats = Guarded prognosis Dermal melanoma in dogs = Most common on eyelids</p> Signup and view all the answers

    Which of the following statements about dermal melanomas in dogs is correct?

    <p>Cutaneous melanomas can develop anywhere but are common on the eyelids</p> Signup and view all the answers

    Cutaneous plasmacytomas in dogs are rarely associated with multiple myeloma.

    <p>True</p> Signup and view all the answers

    What is the characteristic appearance of the nucleus in cells of a plasmacytoma?

    <p>Clock-face nucleus</p> Signup and view all the answers

    Approximately _____% of dogs with nail-bed melanomas will have developed metastases by diagnosis.

    <p>30</p> Signup and view all the answers

    Match the following terms with their descriptions:

    <p>Soft tissue sarcoma = Infiltrative and can metastasize Equine collagenolytic granuloma = Confused with equine MCTs Dermal melanoma = Common in dogs, cats, and horses Feline plasmacytoma = More commonly develops on lower limbs</p> Signup and view all the answers

    What percentage of cutaneous plasmacytomas may recur after excision?

    <p>10%</p> Signup and view all the answers

    Surgical excision of dermal melanoma in dogs is usually curative if done correctly.

    <p>True</p> Signup and view all the answers

    Name one common location for plasmacytomas to develop in dogs.

    <p>Mouth</p> Signup and view all the answers

    Soft tissue sarcomas can metastasize, but more frequently result in __________ recurrence.

    <p>local</p> Signup and view all the answers

    What is a common misconception regarding equine mast cell tumors?

    <p>They do not develop in horses</p> Signup and view all the answers

    Study Notes

    Neoplastic Tumors

    • Skin masses are commonly seen in companion animals and pose both diagnostic challenges and economic opportunities for veterinarians.
    • Primary skin neoplasms are more prevalent than metastatic neoplasms from other body sites.
    • Definitive diagnosis is crucial for selecting appropriate treatment, which can include observation, surgical excision, or chemotherapy.
    • Cytology is the primary diagnostic test for skin tumors, often using fine needle aspiration.
    • For surface-oriented masses, such as squamous cell carcinomas, tissue scrapes may be more effective than aspiration.
    • Cytology is cost-effective, requires no sedation, and provides rapid results, typically within 24 hours if sent to a laboratory.
    • Differentiating between inflammatory and neoplastic processes is important for treatment planning and client communication.
    • The most common benign skin tumors in dogs include histiocytomas, lipomas, follicular cysts, sebaceous hyperplasia/adenomas, and basal cell tumors.
    • Malignant potential in skin tumors is primarily associated with mast cell tumors, which rank sixth among common canine skin tumors.

    Non-Neoplastic Tumors

    • Non-neoplastic tumors arise from non-neoplastic cells and can either resolve spontaneously or require surgical excision.
    • Inflammatory tumors may result from bacterial, viral, or fungal infections, or trauma, and can often be treated conservatively.
    • Nevus (focal adnexal hyperplasia) consists of benign collagen or adnexa and requires excision only if symptomatic.
    • Sebaceous gland hyperplasia frequently occurs in certain dog breeds and appears as wart-like growths; excision is curative but multiple lesions may develop over time.
    • Follicular cysts (dermal cysts) form from malformed hair follicles that trap keratin, often leading to inflammation and possible rupture.
    • Calcinosis circumscripta develops as a nodular mass, predominantly in young large breed dogs, resulting from dystrophic calcification due to trauma.

    Possibly Neoplastic Tumors

    • Canine cutaneous histiocytomas are the most common benign skin tumors in dogs, characterized by localized histiocyte proliferation with spontaneous resolution in weeks.
    • Lipomas, subcutaneous fat deposits, are the second most common skin tumor, typically mobile and benign, requiring excision only if they interfere with function.
    • Hemangiomas are well-differentiated vascular tumors, often associated with solar exposure; complete excision is curative.

    Primary Skin Neoplasms

    • Epithelial neoplasms arise from skin adnexal structures and are classified as adenomas (benign) or adenocarcinomas (malignant).
    • Benign sebaceous and apocrine gland adenomas account for 10% of canine skin neoplasms and are commonly found on eyelids, limbs, and trunk.
    • Basal cell tumors, common in dogs, cats, and horses, arise from follicular basal cells and can be pigmented; excision is curative.
    • Follicular neoplasms include trichoepithelioma, pilomatricoma, and intracutaneous cornifying epithelioma and are mainly benign.
    • Squamous cell carcinoma is the most common malignant epithelial neoplasm, particularly in cats, linked to UV exposure and presenting as ulcerated lesions.
    • Hepatoid gland adenomas, testosterone-responsive skin tumors in dogs, resemble hepatocytes on cytology and are most common in uncastrated males.### Hepatoid Gland Adenomas vs. Apocrine Gland Adenocarcinomas
    • Hepatoid gland adenomas develop externally around the anus, detectable by touch.
    • Apocrine gland adenocarcinomas arise within the anal sacs, presenting as diffuse perineal swelling.
    • Hepatoid gland adenomas are benign, testosterone-responsive, with no systemic effects.
    • Apocrine gland adenocarcinomas can produce PTH-rp, are infiltrative, metastatic, and often fatal.
    • Castration reduces the likelihood of hepatoid gland adenomas, prostatic disorders, and testicular tumors.

    Mammary Gland Tumors in Dogs and Cats

    • Common in both dogs (50-80% benign) and cats (almost always malignant).
    • Early spaying significantly lowers the risk of mammary neoplasms in dogs.
    • Canine mammary tumors often feature glandular structures with anaplastic cells, and bone and cartilage may be present.
    • Tumors that are harder and more nodular tend to be benign.
    • Cytology is often inadequate for differentiating mammary adenomas from adenocarcinomas.
    • Feline mammary adenocarcinomas metastasize quickly and may spread to skin.
    • Tumor size is critical for prognosis in cats; larger tumors indicate worse outcomes.
    • Early spaying does not impact mammary cancer risk in cats.

    Round Cell Neoplasms

    • Round cells originate in the bone marrow and travel to skin, losing mobility upon settling.
    • Low interaction between these cells leads to distinct cytological features.

    Mast Cell Tumors (MCTs)

    • MCTs are the 6th most common tumors in dogs and 21% of feline skin tumors.
    • Nearly all feline MCTs are benign, while canine MCTs can be malignant with variable behavior.
    • Diagnosis typically via cytology, revealing round cells with dark purple granules.
    • Canine MCTs can be low or high grade based on histological invasion and differentiation.
    • Low-grade canine MCT removal is often curative; however, recurrence occurs in 5-15%.
    • High-grade MCTs have poorer prognoses and can metastasize early.
    • Feline cutaneous MCTs are usually benign and localized; surgical excision is curative.

    Cutaneous Plasmacytoma

    • Occur in dogs mainly in the mouth, feet, and pinnae; rare in cats.
    • Cytology shows non-cohesive round cells with a characteristic ‘clock-face’ nucleus.
    • Generally do not recur locally, but new plasmacytomas may arise.
    • Cats are more likely to develop plasmacytomas linked to multiple myeloma, which affects prognosis.

    Spindle Cell Tumors

    • Develop from connective tissue; soft tissue sarcomas are a common type in dogs.
    • Cytology often shows spindle-shaped cells within visible bundles.
    • Can be infiltrative despite seeming encapsulated; local recurrence is about 30%.
    • Complete excision attempts should prioritize wide margins to reduce recurrence risks.

    Dermal Melanoma

    • Common in dogs, its behavior varies depending on skin location.
    • Non-haired skin melanomas (e.g., nail-bed, mucocutaneous junction) are generally malignant.
    • Canine melanomas on haired skin are often benign; complete excision is typically curative.
    • Feline and equine melanomas are often malignant and affirmatively require careful monitoring.

    Cutaneous Hemangiosarcoma

    • Primarily affects older dogs, induced by sunlight; often found on the ventrum.
    • Typically, only metastasize late in progression; multiple lesions can develop.
    • Excision is usually effective, but preventive measures against sun exposure are imperative.

    Equine Sarcoid

    • Most common skin tumor in horses, associated with bovine papillomavirus (BPV).
    • Develops variably in clinical presentation, usually in trauma-prone areas.
    • Cytology reveals spindle-shaped cells, while histology shows fibroblast proliferation without metastasis.
    • Local recurrence is common, and treatment remains inconsistent.

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    Description

    This quiz focuses on the identification and implications of neoplastic and non-neoplastic tumors, particularly those that develop on the skin of companion animals. Understanding these masses is crucial for veterinarians to provide appropriate treatment plans and effectively address client concerns. Test your knowledge on this important topic in veterinary medicine.

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