Canine Lipomas Treated with Steroid Injections: Clinical Findings

Abstract

Lipomas are common benign tumours of fat cells. In most cases, surgical excision is curative and simple to perform; however, such a procedure requires general anaesthesia and may be associated with delayed wound healing, seroma formation and nerve injury in deep and intramuscular tumours. The objective of this study was to evaluate treatment of subcutaneous, subfascial or intermuscular lipomas using intralesional steroid injections in dogs. Fifteen dogs presenting with lipomas were selected for treatment with ultrasound-guided intralesional injection of triamcinolone acetonide at a dose of 40 mg/mL. Nine subcutaneous and subfascial tumours showed a complete regression. The other lipomas decreased in diameter, achieving, in some cases, remission of discomfort and regression of lameness. Steroid injection was a relatively safe and effective treatment for lipomas in dogs; only six dogs experienced polyuria/polydipsia for about 2 weeks post-treatment.

Mandibular infiltrative lipoma in a mixed breed dog

“…The cellular and histological features of simple lipomas and infiltrative lipomas are often very similar. A biopsy sample without including adjacent normal tissue may lead to an erroneous diagnosis of simple lipoma (Bergman and others 1994, Lamagna and others 2012). Definitive diagnosis of an infiltrative lipoma is based on finding adipocyte infiltration of muscles or fascia at the time of surgery and the biopsy will also confirm the gross surgical findings.…”

“…CT is a good imaging modality to assess the extent of infiltrative disease as it has excellent spatial resolution and provides cross-sectional images without superimposition (McEntee and others 2001). The adipose tissue in infiltrative lipoma has lower attenuation (typically less than −20 HU), which contrasts well with the surrounding muscle on CT images (Lamagna and others 2012, Nakladal and others 2012). Irregular shape of the mass, partial or complete ill-defined margins and the linear hyperattenuating striations relative to the surrounding fat on CT images were considered parameters that favoured a diagnosis of infiltrative lipoma (Spoldi and others 2017).…”

“…Irregular shape of the mass, partial or complete ill-defined margins and the linear hyperattenuating striations relative to the surrounding fat on CT images were considered parameters that favoured a diagnosis of infiltrative lipoma (Spoldi and others 2017). Therefore, in cases of suspected infiltrative lipoma, CT should be considered prior to surgery to allow assessment of extent of local infiltration allowing planning for wide resection (Lamagna and others 2012, Nakladal and others 2012). MRI is another cross-sectional imaging modality capable of assessing the local invasiveness (Nakladal and others 2012).…”

“…It is difficult to determine the benefit of radiation therapy, but it may provide benefit when there are residual tumour cells in situ following surgical resection. Ultrasound-guided intralesional injection of triamcinolone acetonide was described by Lamagna and others (2012). Nine of the 15 dogs with subcutaneous and subfascial lipomas showed a complete regression; the other lipomas decreased in diameter (Lamagna and others 2012).…”

“…Infiltrative lipomas have been reported in a variety of locations in the dog, including pelvic limbs, vessels, spinal canal, cervical bones, forelimbs, face and larynx (Kim and others 2005, Morgan and others 2007, Lamagna and others 2012, Agut and others 2013, Brunnberg and others 2013, Hobert and others 2013). Wide or radical surgical resection is the treatment of choice for infiltrative lipomas; however, infiltrative lipomas of the head pose a unique problem given the proximity to multiple vital structures.…”