L60b: tumors in large animals

what is the diagnostic workflow for a mass in large animals?

1. history and exam

2. sample the lesion

3. review the smear

4. choose the next test

what abnormal nuclear detail will make you consider malignancy?

1. large or irregular nucleoli

2. abnormal mitoses

3. unequal nuclei within one cell

what tumor do you consider in equine if you see a lesion on the skin, scars, eyelids, or limbs?

sarcoid

A client calls you to examine a mass on their horse. Upon examination, the mass appears variable in shape and the surface looks irregular, making it appear like a wart. What do you expect the mass to be?

sarcoid tumor

what tumor are you thinking of in equine if the lesion is under the tail or around the anus?

melanoma

what tumor are you considering in equine if you see a lesion on the eye or external genitalia?

squamous cell carcinoma

A client calls you to examine a mass on their horse. The client informs you that the mass has been a “ persistent ulcer or proliferative lesion”. Based on the client’s description, what tumor are you thinking this horse may have?

squamous cell carcinoma

what tumor are you thinking of in equine if you see a lesion on lymph nodes, gut, skin, or body cavities?

lymphoma

what is a useful clue for lymphoma in horses?

local or systemic disease

what type of tumor is an equine sarcoid?

mesenchymal tumor

what may you see for an equine sarcoid?

a flat, warty, nodular, or fleshy skin lesion

what may the aspirate miss when doing an equine sarcoid sample?

1. fibrous lesions often yield few cells

2. spindle cells can overlap with reactive fibroplasia

what can help confirm diagnosis for equine sarcoid?

histopathology

what is the interpretation of equine sarcoids?

locally aggressive behavior

what is the cytology for equine sarcoid?

often poorly cellular

what is the typical presentation of equine melanoma?

an older grey horse with nodules beneath the tail or around the perinium

what is the cytologic clue for equine melanoma?

1. melanin within melanocytic cells

2. cells may be round, spindle-shaped, or epithelioid

what is the gross appearance of equine melanoma?

often dark nodules

what is the cytology of equine melanoma?

pigment within tumor cells

what type of tumor is equine squamous cell carcinoma?

epithelial tumor

what are the common locations for equine squamous cell carcinoma?

1. periocular tissues

2. external genitalia

3. gastric SCC

what are cytology clues for equine squamous cell carcinoma?

1. atypical squamous cells

2. variable keratinization

3. nuclear abnormalities

what diagnostic test assesses invasion of equine squamous cell carcinoma?

biopsy

what is the gross appearance of equine squamous cell carcinoma?

proliferative or ulcerated lesions

how may equine lymphoma appear under microscope?

expanded atypical lymphoid population

how may mast cell tumor in equine look like under microscope?

purple cytoplasmic granules

what tumor are you thinking in bovine if you see a lesion on the eye surface?

ocular squamous cell carcinoma

what tumor are you thinking in bovine if you see enlarged nodes or multiple organ lesions?

lymphoma

what tumor are you thinking in bovine if you see abomasal thickening, melena, or outflow signs?

lymphoma

what tumor are you thinking in bovine if you see a exophthalmos, paresis, or cardiac signs?

consider the site of a possible internal mass

what is important to know about internal tumors in bovine?

can present as organ disease without an obvious external mass

what is the enzootic form of bovine lymphoma?

associated with bovine leukemia virus usually in adult cattle

what are the sporadic forms of bovine lymphoma?

Juvenile multicentric, thymic, and cutaneous forms occur independently of BLV

what do we do to confirm the lesion for bovine lymphoma?

1. aspirate affected area

2. obtain tissue for histopathology

what increases suspicion for bovine ocular squamous cell carcinoma?

1. an animal with a persistent ocular lesion

2. UV exposure and limited pigmentation contribute to risk

what can the sample show for bovine ocular squamous cell carcinoma?

atypical squamous cells with keratinization and inflammation

what is ovine pulmonary adenocarcinoma?

an epithelial lung tumor in sheep

what is the clinical pattern of ovine pulmonary adenocarcinoma?

1. progressive weight loss

2. respiratory difficulty

3. lung fluid may be prominent

what is a possible explanation for anemia?

1. inflammation

2. bleeding

3. marrow disease

what is a possible explanation for altered proteins?

1. low albumin

2. increased globulins

what is a possible explanation for effusion?

1. inflammation

2. obstruction

3. tumor spread

what steps helps next for anemia?

1. find trends for CBC

2. examine blood smear

what steps help next for altered proteins?

assess losses, inflammation, and hydration

what steps help next for organ dysfunction?

localize with imaging

what steps help next with effusion?

evaluate fluid cells and underlying lesion

what steps help next for hypercalcemia?

confirm ionized calcium

what diagnostic pitfall can occur with few cells?

sampling error or poor exfoliation can hide tumor

what diagnostic pitfall can occur with marked inflammation?

reactive atypia may mimic malignancy

what diagnostic pitfall can occur with necrosis or blood?

useful tissue cells may be sparse or damaged

what diagnostic pitfall can occur with pigment or unusual cells?

identify the cell carrying the pigment and check the whole smear