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592.e2 Liposarcoma

Liposarcoma Client Education
Sheet
VetBooks.ir Recommended Monitoring

BASIC INFORMATION
is often helpful in defining the extent of the
tumor. After appropriate local treatment, regular
Definition follow-up exams are indicated to monitor
An uncommon primary malignant neoplasm of Differential Diagnosis for recurrence (q 2-3 months) and metastases
adipocytes; can occur anywhere in the body but Other skin and subcutaneous tumors: (including thoracic radiographs at 6 months and
more commonly found in the skin and subcutis. • Soft-tissue sarcoma 1 year). High-grade tumors may require more
• Mast cell tumor frequent monitoring for metastases during and
Epidemiology • Lipoma after chemotherapy administration.
SPECIES, AGE, SEX • Others (p. 628)
Uncommon in dogs (generally > 10 years old) Other splenic tumors: PROGNOSIS & OUTCOME
and rare in cats (may occur at injection sites) • Hemangiosarcoma
• Lymphoma • Early studies reported metastasis to multiple
RISK FACTORS • Others sites (liver, lung, bone), but in a subsequent
Liposarcomas have been reported in previously study of 56 dogs, very few dogs died as a
irradiated tissues, at the site of a glass foreign Initial Database result of metastasis (median survival ≈2 years
body, and at the site of an injected microchip. • Fine-needle aspiration and cytologic analysis or >3 years with wide tumor excision).
The limited number of cases suggests that these may help identify tumor type before other • Surgical excision with a clean histopathologic
factors may have a small impact on the risk of diagnostic tests. margin may not be adequate for local control
developing liposarcoma. • Three-view thoracic radiographs to rule out in some dogs based on a recurrence rate
pulmonary metastases of 31% for dogs with clean margins and a
Clinical Presentation • Radiographs of the affected area may (rarely) higher risk of recurrence after re-excision.
DISEASE FORMS/SUBTYPES reveal involvement of underlying bone. • Palliative radiation after incomplete excision
Liposarcomas have different pathologic sub- • Fine-needle aspiration of draining lymph results in tumor control in 65% of dogs with
types, but they have not been shown to have nodes to help rule out metastasis soft-tissue sarcomas at 5 years according to
prognostic significance. one study.
Advanced or Confirmatory Testing • Metronomic chemotherapy using cyclo-
HISTORY, CHIEF COMPLAINT • CT or MRI may be necessary to delineate phosphamide and piroxicam has resulted
• Dogs and cats with liposarcoma in the the local extent of the tumor and plan for in tumor control for more than 400 days
skin and subcutis tissue usually present for surgery or radiation therapy. after incomplete tumor excision of soft-tissue
evaluation of a progressively growing mass • CT may help differentiate liposarcomas from sarcomas.
noticed by the owner. lipoma and infiltrative lipoma.
• Dogs with abdominal liposarcoma often • Biopsy: definitive diagnosis is based on PEARLS & CONSIDERATIONS
present for evaluation of signs related to an histopathologic exam of tissue. Special stains
abdominal mass. may be necessary to differentiate liposarcoma Comments
from other soft-tissue sarcomas, especially Fine-needle aspirates of skin and subcutaneous
PHYSICAL EXAM FINDINGS poorly differentiated tumors. masses should always be evaluated micro-
• Liposarcoma in the skin and subcutis often scopically. Aspirates of liposarcoma may give
presents as a firm, palpable mass. TREATMENT fatty-appearing fluid, which could falsely be
• Regional lymphadenopathy may be second- interpreted as indicating lipoma or subcutane-
ary to inflammation or (rarely) lymph node Treatment Overview ous fat. Liposarcoma can be readily differenti-
metastasis. Definitive treatment is based on complete ated from benign tumors of adipocytes such
• Dogs with an abdominal liposarcoma may removal of the primary tumor when pos- as lipoma or infiltrative lipoma with routine
present with abdominal mass, pain, or sible. However, additional treatment such as microscopic (cytologic) evaluation of smears.
enlargement. chemotherapy may be indicated to prevent or
delay metastases or used in dogs with high- Prevention
Etiology and Pathophysiology grade tumors or tumors that have metastasized. The individual case of liposarcoma developing
• Thought to be spontaneously occurring in Palliative treatment options, such as palliative at the site of an implanted microchip does not
most cases in dogs, but there are reports of radiation therapy, may help control pain or warrant concern about an increased risk of
tumors developing at the site of foreign bodies. discomfort in patients with advanced tumors or tumors caused by microchips.
• Pathologic changes caused by liposarcomas when definitive treatment cannot be tolerated.
depend on the location of the primary tumor Technician Tips
and the invasion into and destruction of Acute General Treatment • Masses that aspirate as fat but are firm
surrounding normal structures. • Aggressive surgical resection, radiation and growing rapidly or invasive should be
• Not thought to be malignantly transformed therapy, and/or chemotherapy may be used biopsied or removed to confirm the diagnosis.
lipomas for treatment of liposarcoma. • The use of body maps to denote the loca-
• May grow rapidly • Although response to radiation and che- tion and size of subcutaneous masses is very
motherapy has not been determined, these helpful in tracking which are new and require
DIAGNOSIS treatments may be useful as adjuvant therapy. evaluation; this is especially important in
older animals with multiple masses.
Diagnostic Overview Possible Complications
Definitive diagnosis can be confirmed only Complications of treatment for liposarcomas Client Education
by histopathologic analysis of tissue, although depend on the types of treatments and location Pet owners can be educated to monitor their
additional testing such as diagnostic imaging of the primary tumor. pets for masses and have them evaluated in a

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