Infiltrative angiolipoma of the parotid salivary gland in a dog : clinical communication

Abstract

Solitary benign angiolipoma and infiltrative angiolipoma are rare tumours in dogs. Angiolipomata can be distinguished histologically from lipomata by the large number of tightly packed blood vessels seen between the adipocytes with multiple fibrin thrombi occupying some of the vessels' lumens. The dog presented with a solitary slow-growing mass in the cervical region. Histopathology revealed multifocal to coalescing single or clusters of blood-filled vessels lined by flattened endothelial cells with narrow, elongated, basophilic nuclei. These regions were embedded in adipose tissue with multifocal areas of intervascular remnants of differentiated serous salivary glandular tissue with multifocal small ducts. Fibrin thrombi occupied a few of the vessel lumens. A histological diagnosis of infiltrative angiolipoma was made. On computed tomography, the mass was bilobed with a suspected primary component involving the right parotid gland which was grossly enlarged. The mass had a slightly hypoattenuating mottled to lobulated appearance with a few hyperattenuating mineralised specks throughout. Hounsfield units of the mass ranged between 40 and 45, which was less than the 60-65 of the contralateral salivary glands and cranial musculature. Post contrast images showed no contrast enhancement of 90% of the mass with only a band of peripheral contrast uptake of the affected lateral lobe

Imaging Diagnosis—computed Tomographic, Surgical, and Histopathologic Characteristics of an Infiltrative Angiolipoma in a Dog

“…Infiltrative angiolipomas occur more often in older patients . The infiltrative angiolipoma reported here, as well as two previously published canine cases . occurred on the neck.…”

“…The pathogenesis behind the formation of angiolipomas is unknown, though trauma has been suggested as a possible cause in humans . Angiolipomas in humans are reported to be painful; this does not appear to be the case in the patient described here, nor has tumor‐associated pain been described in previous veterinary patients …”

“…In contrast, these tumors, especially the infiltrative form, continue to be rarely reported in domestic animals. To the authors’ knowledge, only four previous cases of infiltrative angiolipoma have been reported in dogs …”

“…Due to the apparent scarcity of angiolipomas, and especially infiltrative angiolipomas, in veterinary medicine, descriptions of the imaging, gross, and histopathologic characteristics of these tumors are limited. While diagnosis of neoplasms has been enhanced by the availability of CT only two previous reports of the CT appearance of canine infiltrative angiolipomas have been published . The first report described a 12‐year‐old Labrador Retriever with a lipomatous mass occupying the spinal canal and several lumbar vertebral bodies.…”

Infiltrative Cutaneous Hemangiolipoma in a Goat

“…In humans, hemangiolipomas have been reported in the subcutis of the thorax, spine, gastrointestinal tract, and bone [4–6]. In dogs, individual case reports exist of angiolipomas arising in skin, bone of the spinal canal and parotid salivary gland [3, 7, 8]. A pericardial hemangiolipoma was reported in one bull [9].…”