Lipoma in Cats (Felis) | Vetlexicon
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Lipoma

ISSN 2398-2950

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Introduction

  • Lipomas are uncommon, but not rare, in cats.
    • Unlike dogs, subcutaneous lipomas very uncommon - although the true incidence is uncertain since many tumors are diagnosed clinically and not submitted for biopsy.
    • May be found in a variety of locations.

Presenting signs

  • Subcutaneous mass.
  • Intra-abdominal mass.
  • Most common sites for cutaneous lipoma include abdomen, thorax, limbs.
  • Less common sites for cutaneous lipoma include back, neck, head, tail and perineum.
  • One survey noted 5% of cases had multiple lipomas.
  • Siamese Siamese may have a breed predisposition.
  • Commonly in cats aged 6-11 years, but range is is 1-18 years.
  • Male neutered cats are more at risk
  • Neurologic if associated with spinal cord.

Acute presentation

  • Rare.

Pathogenesis

Etiology

  • No known etiology.

Predisposing factors

General

  • Benign growth of adipocytes, will grow slowly over time but will not invade or metastasize.

Diagnosis

Client history

  • Owner notices lump on cat.
  • Other clinical signs dependent on site.
    • Enlarged abdomen.
    • Neurologic.

Clinical signs

  • If subcutaneous, mass is soft, circumscribed, non-fixed.
  • If abdominal, abdominal distension noted, possible mass palpated.

Diagnostic investigation

  • Radiographs of abdomen Radiography: abdomen will show fat density mass.
  • Excised mass floats in formalin or water.

Definitive diagnostic features

  • Fine needle aspirate Fine-needle aspirate and cytology Cytology: fine needle aspiratewill reveal benign adipocytes.
  • Tru-cut biopsy Biopsy: skin can be performed if unsure of diagnosis, but if infiltrative lipoma is suspected a larger biopsy is often needed to demonstrate infiltration into surrounding tissues.
  • Excisional biopsy is a common approach for small masses.

Histopathology findings

  • Microscopically lipoma is identical to normal adipose tissue.
  • Round to polygonal cells with a peripheral small, dense nucleus and clear large cytoplasmic vacuole (fat dissolves out in the organic solvents used during processing).
  • Rare infiltrative variants (rare in cats compared with dogs) show invasion into surrounding tissues, such as muscle.

 

Differential diagnosis

Treatment

Initial symptomatic treatment

  • Surgical excision is curative:
    • If subcutaneous mass, treatment optional.
    • If abdominal mass, mass effect may compress abdominal organs and removal is recommended.
    • For rare other sites (eg extradural spinal mass), excision is curative.
    • No evidence of progression to liposarcoma.

Prevention

Outcomes

Prognosis

  • Excellent prognosis.
  • The rare infiltrative lipoma has a guarded prognosis due to recurrence associated with local invasion and difficulty in clean resection.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Levy M S, Mauldin G, Kapatkin A S et al (1997) Nonlymphoid vertebral canal tumors in cats: 11 cases (1987-1995). J Am Vet Med Assoc 210 (5), 663-664 PubMed.
  • Plummer S B, Bunch S E, Khoo L H et al (1993) Tethered spinal cord and an intradural lipoma associated with a meningocele in a Manx-type cat. J Am Vet Med Assoc 203 (8), 1159-1161 PubMed.
  • McCaw D L, da Silva Curiel J M & Shaw D P (1990) Hepatic myelolipomas in a cat. J Am Vet Med Assoc 197 (2), 243-244 PubMed.

Other sources of information

  • Goldschmidt M H and Shofer F S (1992) Chapter 24. Cutaneous lipoma and liposarcoma. In: Skin Tumours of the dog and cat. pp 192-203. Pergamon Press, Oxford.
  • Yager J A and Wilcock B P (1994) Chapter 20. Other cutaneous mesenchymal tumours. In: Color atlas of surgical pathology of the dog and cat. Dermatopathology and skin tumors. pp 297-307. Wolfe, London.