Читать книгу Veterinary Surgical Oncology - Группа авторов - Страница 157

Infiltrative lipomas have been described in dogs and in cats. Histologically, they are composed of well‐differentiated fat cells. They are considered benign and do not metastasize. They tend to expand, however, and infiltrate between surrounding tissues including muscle, fascia, nerve, myocardium, joint capsule, periosteum, and bone. Clinically, they may be painful, are less well defined than lipomas, and palpate as a firm or solid mass because of their infiltrative behavior. Definitive diagnosis is made by the histologic evaluation of surgically excised tissue at the edge of the tumor and adjacent normal tissue. Preoperative evaluation with CT and MRI imaging can be helpful to discriminate tumor from normal tissue (muscle, etc.) (Kim et al. 2005; McEntee and Thrall 2001). Tumor definition and shape have been reported as the most useful parameters in computer tomography to differentiate between lipomas and infiltrative lipomas (Spoldi et al. 2017).

Complete surgical excision is curative; however, this is complicated by the difficulty in distinguishing tumor tissue from normal fat and their infiltrative nature (most often in muscle), which both can result in incomplete resection and tumor recurrence (Kim et al. 2005). In a study of Bergman et al. (1994), a recurrence rate of 36% was reported after aggressive surgical resection. Dogs with infiltrative lipoma may benefit from external beam irradiation alone or in combination with surgery, or multiple cytoreductive surgeries, resulting in long‐term local tumor control (McEntee et al. 2000). An 11‐year‐old Labrador retriever suffering from pelvic limb paraparesis caused by an infiltrative lipoma resulting in spinal cord compression at the fifth thoracic intervertebral space recovered to full ambulatory after mass removal by hemilaminectomy and survived over 24 months after surgery (Morgan et al. 2007). Also, Hobert et al. (2013) reported two dogs with histologically confirmed infiltrative lipoma causing spinal cord compression. In our experience, surgical liposuction of the mass of the tumor leads to DFIs of approximately one year.

Intermuscular lipoma of the thigh is often misdiagnosed as an infiltrative lipoma. An accurate diagnosis is important such that the appropriate treatment is performed. Intermuscular lipomas are treated by marginal excision whereas infiltrative lipomas of the thigh are sometimes treated by amputation or radiation therapy.