Background: Malignant peripheral nerve sheath tumors are neurogenic neoplasms that originate from cells that surround the axons of peripheral nerves. Surgery is the treatment of choice for peripheral nerve sheath tumors. They have a better prognosis when the lesion is in the extremity of a limb and the surgeon leaves wide peripheral margins after resection. However, this procedure makes local treatment a challenge due to difficult wound healing in this region. This report describes a successful case involving the use of a meshed skin graft immediately after resection of a neurofibrosarcoma in the distal region of the radius bone of a dog.Case: A 6-year-old Boxer bitch weighing 40 kg was admitted with a history of a round, firm, non-ulcerated skin nodule attached to the lateral side of the distal region of the right radius bone, which had been present for about 40 days. Fine needle aspiration cytology of the lesion showed the presence of mesenchymal cells, suggesting a sarcoma. Thus, the decision was made for an incisional biopsy to confirm the diagnosis and for the preparation of a subdermal pattern tubular flap for subsequent rotation and transposition to close the wound that would be formed after the complete removal of the lesion. After the 7th postoperative day, the diagnosis of low-grade neurofibrosarcoma was confirmed and due to the presence of necrotic onset in the middle portion of the tubular flap, further surgical intervention was scheduled for the resection of the tube flap, en bloc removal of the neoplastic lesion with peripheral margins of 2 cm, and wound closure with a free skin graft. A mesh skin graft was made with a portion of the right flank skin. The mesh graft was carefully implanted on the recipient bed using simple interrupted sutures with a 3-0 non-absorbable monofilament suture material. A dressing made with water-based sterile lubricating solution and gauze and a modified Robert Jones bandage were applied. The patient was treated with analgesic medication, antimicrobial therapy, and gastric protectors. The first bandage and dressing were changed after 48 h, and only warm physiological solution was used. Histopathological analysis confirmed the diagnosis of low-grade neurofibrosarcoma with free surgical margins. The dressing was changed every 72 h for up to 12 postoperative days, when the immobilization was removed, and wound cleaning could be completed at home using physiological solution and a dressing with nitrofurazone ointment. Granulation tissue was first seen at day 12, and at day 30 the wound was completely closed.Discussion: The primary closure of skin defects after the resection of tumors located in the distal portion of limbs is often not possible due to a lack of adjacent skin. Thus, grafts are commonly used to repair the skin in these areas using the technique presented in this report. In order to survive, skin grafts need a vascular bed capable of allowing new blood vessel connections with the implanted skin portion. There is no consensus in the literature on the best bed for graft implantations. In the case described in this study, a free mesh graft was implanted on a fresh wound without granulation tissue, which resulted in excellent clinical evolution and total survival of the graft. Excellent clinical results were achieved with the graft, since its survival and adherence to the recipient bed occurred without complications. The clinical result of this case suggests that the application of full-thickness mesh grafts to fresh wounds in distal limbs immediately after tumor resection is a good alternative when the surgical wound is too large (which prevents primary closure). Good preoperative planning associated with good surgical techniques and adequate postoperative management are essential for the success of the technique under these conditions.

Background: Lipomas are benign soft tissue mesenchymal neoplasms composed of adipose cells and are usually found in the subcutaneous tissue. Occasionally, lipomas may invade muscles or grow between them, in which case they are characterized as infiltrative lipomas. Clinical signs resulting from an intermuscular lipoma compressing peripheral nerves are rarely encountered in dogs. This case report aims to describe the neurological signs, diagnosis, and clinical evaluation of a dog diagnosed with infiltrative lipoma compressing a lumbar spinal nerve root. Case: A 12-year-old neutered male Fox Paulistinha, weighing 10.5 kg, was presented with difficulties in walking for the past 15 days with no previous history of trauma. On physical examination, the presence of three cutaneous nodules was noted in the ventral thoracic region, with onset of one year and slow and progressive growth. A cytological evaluation of the nodules was performed, and lipoma was diagnosed. At the neurological examination, the patient presented ambulatory paraparesis with marked motor deficit and atrophy of the quadriceps muscles of the left pelvic limb. Conscious proprioceptive deficit, the absence of patellar reflex, and diminished withdrawal reflex were observed in the left hind limb, in addition to diffuse pain on epaxial palpation of the lumbar region. Electroneuromyography showed increased insertion activity in the left gastrocnemius muscle and moderate spontaneous activity (fibrillation). Persistence of 10% was observed in the F-wave study of the left tibial nerve. These findings indicate partial involvement of the roots of the left sciatic-tibial nerve. Magnetic resonance imaging (MRI) showed the presence of a mass measuring 3.18 × 1.04 × 1.4 cm, interspersed with the paravertebral muscles, and located adjacent to the L2 and L3 spinous processes. An ultrasound-guided fine needle aspiration biopsy of the mass was performed and the findings of the cytopathological analysis of the collected material were considered consistent with lipoma. In view of these findings, surgical removal was recommended. However, the owner chose to attempt conservative treatment to control pain. Thus, the patient was treated with gabapentin, tramadol hydrochloride, carprofen, dipyrone, omeprazole, and physiotherapy. The animal exhibited a good response to conservative treatment, regaining its hind limb mobility in approximately 30 days. Discussion: Infiltrative lipomas compressing nerve roots are rarely described, with only one report of infiltrative lipoma in the lumbar region causing nerve root compression in dogs found in the literature. MRI was beneficial in this case, since it helped in determine the shape, location, and extent of the mass causing compression of the left L2 nerve root. The history and neurological examination findings in the patient described in this report were accounted for by the presence of an infiltrative lipoma compressing the left nerve root of L2. Surgical excision is the treatment of choice for intramuscular lipomas in most cases sin...