OBJECTIVE: To describe the treatment of subcutaneous lipomas in the horse.
METHODS: 3 horses.
METHODS: The horses were aged 1 to 2 years old, with lipoma of the abdomen, prepuce, and tarsus.
RESULTS: All cases had surgical removal of the masses under general anesthesia. Recurrence of an invasive abdominal lipoma occurred in case 1 at the exit site of a passive drain. The recurrence was treated unsuccessfully with injectable cisplatin, and a second revision surgery with the use of an active drain resulted in resolution. In case 2, complete resection of an encapsulated lipoma of the lateral prepuce was successful with no recurrence. In case 3, incomplete resection of a tarsal lipoma resulted in a sound horse, with no further growth. Histopathologic analysis revealed that all masses were composed of well-differentiated adipocytes with no evidence of malignancy.
CONCLUSIONS: Subcutaneous lipomas are relatively rare and affect horses primarily ≤ 2 years of age. They are benign, although their presence can be deleterious due to invasion of local structures or the impact on normal locomotion. The margins of invasive tumors are difficult to identify due to their integration with normal tissue. Incomplete removal may allow for mass recurrence. Active suctions drains are beneficial if dead space is a concern.

This case report details a unique presentation of an infiltrative intramuscular lipoma in the anterior thigh of a 51-year-old female with an overlying fascial defect. The patient reported a progressively enlarging left thigh mass associated with pain exacerbated by knee movement and exercise. MRI revealed a homogeneous intramuscular lipoma without contrast enhancement with a fascial defect. An 8 cm longitudinal incision exposed a 7 x 4 cm fascial defect overlying the lipomatous mass within the rectus femoris muscle. Pathological analysis confirmed an intramuscular lipoma without malignancy. Follow-ups at two, six, and 12 weeks demonstrated pain resolution and no soft tissue bulge. This case underscores the importance of distinguishing intramuscular lipomas from other neoplasms, such as lipomatosis and liposarcomas. The association of a fascial defect with intramuscular lipomas is unprecedented and may be due to the increased pressure on the fascia by the lipoma. The report emphasizes the role of MRI in diagnosis and appropriate surgical management, and highlights the need for further exploration into the etiology of fascial defects associated with intramuscular lipomas.

Infiltrative lipomas, which are locally invasive tumors composed of well-differentiated adipocytes, are histologically identical to lipomas but have a tendency to infiltrate adjacent muscle and fibrous tissue without metastasis, such as muscle; connective tissue; bone; and, in rare cases, peripheral nerves and the spinal cord. They differ from liposarcomas yet also exhibit neoplastic cell infiltration and often recur despite surgical removal. A 10-year-old spayed Maltese female dog presented with hindlimb paresis and back pain for two months. Computed tomography and magnetic resonance imaging revealed an extensive fatty mass impinging on the vertebral canal, compressing the spinal cord, and extending into the surrounding muscle layers and thoracic cavity. The mass was surgically removed, and subsequent postoperative computed tomography confirmed complete removal of the mass using Vitrea® advanced visualization fat measurement. Histopathological analysis confirmed that the mass was an infiltrative lipoma. The patient\'s symptoms completely resolved after surgery, with no recurrence reported at the 2-year follow-up. This case highlights the benefits of using postoperative computed tomography combined with the automated fat measurement technique to determine whether reoperation is necessary or to predict patient prognosis by identifying potential residual lipoma post-surgery.

OBJECTIVE: To describe radiotherapy outcomes for canine infiltrative lipomas and provide detailed radiotherapy planning data.
METHODS: 24 dogs from 2000 to 2020.
METHODS: In this retrospective study, dogs received 1 to 3 surgeries prior to conventionally fractionated radiotherapy for gross (18) or microscopic (8) infiltrative lipomas. Dogs received 45 to 51 Gray (Gy) in 15 to 20 daily fractions, with 71% of dogs receiving 48 Gy in daily 3-Gy fractions.
RESULTS: Masses were regionally located as follows: limbs (7), trunk (13), head/neck (4). At analysis, 16/24 dogs were deceased, 5/24 were alive (median follow-up for alive dogs: 1,216 days [range, 741 to 1,870 days]), and 3/24 were lost to follow-up. One living dog had progressive disease 923 days after completing conventionally fractionated radiotherapy and received another surgery. The estimated median overall survival (OS) after completing radiotherapy was 4.8 years (1,760 days; 95% CI, 1,215 to 2,777 days; range, 23 to 3,499 days) for any cause of death, and no patients were reported to have been euthanized or died from their tumor. No statistically significant difference was found for dogs based on gross versus microscopic disease (gross OS, 4.8 years vs microscopic OS, 3.6 years; P = .45). Furthermore, the number of surgeries before radiotherapy did not impact survival (P = .96). The survival difference between females (median OS, 7.6 years; 95% CI, 963 days to not reached) versus males (median OS, 4.6 years; 95% CI, 335 to 2,245 days; P = .05) was statistically significant, although 4/5 living dogs were female.
CONCLUSIONS: This study demonstrates lengthy survivals with radiotherapy, even with gross disease, for dogs with infiltrative lipomas.

Benign primary cardiac tumours are rare, with lipomas accounting for <9% of them. Their presentation varies depending on the size and location of the tumour, with the majority of the cases being asymptomatic. We are presenting a case of an extremely rare primary heart-tumour infiltrating the right ventricle (RV) compromising its function. RV lipomas are so unusual that there are no clear treatment guidelines. In this case, we decided to treat the patient with surgical resection of the tumour. Although a total resection was not possible, due to the tumoural proximity to vital structures, a great portion of the tumour was removed, alleviating the patient\'s symptoms.

A 4-year-old, male Bernese mountain dog was evaluated for a 1-year history of right hemiparesis. Computed tomography revealed a large hypoattenuating mass severely deforming the C5 vertebral arch, invading the C6 spinal canal, and causing spinal cord compression. The signal characteristics of magnetic resonance imaging indicated a lesion composed of adipose tissue. The mass was removed via right hemilaminectomy, and histopathological examination confirmed it was an infiltrative lipoma. The compressive lesion remained unresolved, so the dog underwent a second operation, after which he regained some ambulatory function. Although postoperative adjunctive radiation therapy was performed, the dog died 201 days after the first operation.

A better understanding of the CT features of different forms of canine and feline adipose tumors would be valuable for improving patient management and treatment. The purpose of this retrospective, cross-sectional study was to describe and compare the CT features of pathologically confirmed lipomas, infiltrative lipomas, and liposarcomas in a sample of canine and feline patients. A total of 50 animals (46 dogs, four cats) and a total of 60 lesions (23 lipomas, 20 infiltrative lipomas, and 17 liposarcomas) were included in the study. Lipomas appeared as round to oval-shaped (n = 21), well-marginated (n = 20) fat-attenuating lesions. Infiltrative lipomas appeared as homogeneous, fat-attenuating masses but, unlike lipomas, they were most commonly characterized by an irregular shape (75%; P < 0.001), and linear components, hyperattenuating relative to the surrounding fat (100%; P < 0.05). Liposarcomas were represented exclusively by heterogeneous lesions with soft tissue attenuating components with a multinodular appearance (76.5%; P < 0.05). Regional lymphadenopathy (n = 10) and amorphous mineralization (n = 4) were also observed in association with liposarcomas. Computed tomography can provide useful information regarding disease location, extent, and involvement of the adjacent structures. Tumor definition and shape were the most useful parameters to differentiate between lipomas and infiltrative lipomas. The presence of a heterogeneous mass, with a multinodular soft tissue component and associated regional lymphadenopathy and mineralization, were features favoring a diagnosis of liposarcoma.

A one-day-old male Holstein calf was presented with a palpable subcutaneous mass, extending from the parotid to the orbital region, involving the entire right side of the face and a large flabby mass without any evidence of inflammation or edema on the tongue. Macroscopically, the cut surface of the lingual mass appeared slightly lobulated, pink, with a mucoid appearance and gelatinous consistency. Histopathological examination confirmed the infiltrative subcutaneous lipoma and lingual myxoma evidenced by low cellularity and abundant basophilic, mucinous stroma. In this report, clinical and detailed histhopathological findings of congenital infiltrative myxoma and its coincidence with infiltrative facial lipoma is reported in a newborn calf.

A 12-year-old, male, fox terrier dog presented with an abnormal gait of the left pelvic limb. Computed tomography revealed a large, homogeneous, hypoattenuating, noncontrast enhancing mass within the left epaxial muscles that invaded the L5-6 vertebral canal and caused spinal cord compression. Imaging findings were consistent with an infiltrative lipoma. The mass was removed and a left hemilaminectomy was performed in the affected area. Histopathology confirmed the mass to be an infiltrative lipoma. The dog recovered and regained neurologic function within 2 weeks. Computed tomography assisted preoperative planning by characterizing the shape, size, and location of the mass.