Schwannomas are the most common peripheral nerve sheath tumors. Benign schwannomas with malignant transformation are rarely reported. Most common schwannomas occur in the head and neck region. Sciatic schwannomas are rare, as are completely cystic schwannomas. Sciatic nerve schwannomas represent less than 1% of all schwannomas. Benign tumors in the sciatic nerve consist of 60% neurofibromas and 38% schwannomas. In general, a schwannoma induces chronic symptoms. It can be misleading, sometimes mimicking degenerative spinal pathology due to disc herniation. Schwannoma involving the sciatic nerve can be asymptomatic or may present with sciatica or neurological deficits. Most schwannomas are solid or heterogeneous tumors, and completely cystic schwannomas are rare. The differential diagnoses of nondiscogenic sciatica include lumbar disc herniation, tumor, abscess, hematoma, facet syndrome, lumbar instability, sacroiliitis, piriformis syndrome, and sciatic neuritis. We report a rare case of a long completely cystic sciatic schwannoma in the left foraminal L5-S1 zone extending to the left ischial groove with chronic sciatica that was diagnosed radiologically with a combination of conventional MRI and MR neurography and confirmed histopathologically by surgical resection. The patient previously had conservative therapy, but the complaints were not reduced. Nonsurgical therapy is considered the first choice, and surgical therapy is indicated in cases that do not respond to conservative therapy, with recurrent cysts, severe pain, or neurological deficits.

Obstetric paralysis is a generic term used to describe postpartum locomotor alterations resulting from nerve damage, widely reported in cattle, but rare in equines. The aim of this study is to report a case of a peripheral polyneuropathy in a primiparous mare, 3 years old, of Mangalarga Marchador breed, after a dystocia lasting approximately 12 hours. At the time of delivery, the head of the fetus was exposed in the vulva and there was flexion of the thoracic limbs. These events culminated in a framework of extreme abduction of the pelvic limbs, thus generating functional impotence and leading the animal to adopt a frog anddecubitus position. After three days of treatment with no improvement in the clinical framework, the animal was euthanized. In the postmortem examination, perineural hemorrhagic lesions were observed in the obturator and sciatic nerves, characterizing the diagnosis of obstetric paralysis. It is possible the outcome of the case would have been satisfactory if there had been an early fetotomy or postpartum treatment had been more prolonged; however, these measures depend on the availability of equipment, conditions of care, and consideration of the owner.

Neuritis of the sciatic nerve is a rare complication of total hip replacements. It is characterized by symptoms of neuropathic pain with or without motor and or sensory symptoms. Causes include direct intra-operative trauma or mechanical lengthening of the nerve. Cases of sciatic nerve neuritis without an organic cause however, are rarer still. We present two cases of sciatic nerve neuritis post total hip replacement with no identified organic cause. Whereas the reversal of the underlying cause has shown improvement in symptoms, in cases without an organic cause our experience advocates close observation and conservative management with spontaneous resolution of symptoms.