No abstract

Double abducens nerve is not a rare variation. Keeping such variations in mind could spare us from injuring the VIth cranial nerve during cranial base operations and transvenous endovascular interventions.

Thinner is a neurotoxic mixture which is widely used as an aromatic industrial solvent. This product has been shown to cause functional and structural changes in the central nervous system. We investigated the effect of exposure to high concentrations (3000 p.p.m.) of thinner for 45 days (1 hr/day) on cognitive functions and the levels of neural cell adhesion molecules (NCAM) and lipid peroxidation products (LPO) in the hippocampus, cortex and cerebellum of rats. The actions of melatonin on the effects produced by thinner exposure were also tested. Thinner exposure caused a significant increase in LPO (malondialdehyde and 4-hydroxyalkenals) in all brain regions. Melatonin administration significantly reduced LPO and elevated glutathione levels in the brain regions. NCAM (180 kDa) was significantly decreased in hippocampus and cortex of thinner-exposed rats. Furthermore, thinner-exposed rats showed cognitive deficits in passive avoidance and Morris water maze tasks, whereas in the rats chronically treated with melatonin these effects were reversed. This study indicates that treatment with melatonin prevents learning and memory deficits caused by thinner exposure possibly by reducing oxidative stress and regulating neural plasticity.

A 57-year-old male patient presented with an immobile ellipsoid mass of 6-cm diameter in the right occipitoparietal region. Cranial computed tomography showed the mass with dense contrast enhancement causing bone destruction. After embolization of the mass, total resection was performed. Histological examination showed the mass had a capsule, with no invasion of the dura mater or dermis, and the follicles of various sizes covered with mono-lined thyrocytes were full of colloid. Immunohistochemical examination showed positive staining for thyroglobulin. Postoperatively, levels of thyroid hormones were normal, and thyroid ultrasonography and technetium-99m scintigraphy showed no abnormalities. Fine needle aspiration biopsy performed at various locations of the thyroid gland revealed no atypical thyroid cells. Whole body technetium-99m scintigraphy found no abnormal bone involvement. The histological evidence was suggestive of follicular carcinoma metastasis. Surgical treatment was planned for the thyroid gland, but the patient did not consent. Two years later, the patient presented with the pain and sensitivity in the sacrum, the right iliac wing, and the right caput femoris. Computed tomography revealed lytic lesions in these areas. Bone metastases were identified. Whole body scintigraphy showed increased activity in these regions, but the cranium and all other tissues were normal. The patient underwent total thyroidectomy under a diagnosis of follicular carcinoma. The present case of a lytic skull lesion associated with normal thyroid tissue on admission but finally treated as follicular thyroid cancer emphasizes the difficulty in histological discrimination of follicular carcinoma from normal thyroid tissue.

No abstract

Melatonin and oxytetracycline are effective in preventing lipid peroxidation in spinal cord injury. Paraoxonase and homocysteine can be used in monitoring the antioxidant defense system as well as superoxide dismutase and plasma glutathione peroxidase, both in injury and medicated groups.

A 26-year-old man with neurofibromatosis type 1 (NF1) presented with a giant malignant schwannoma of the sciatic nerve. The differential diagnosis of malignant peripheral nerve sheath tumor (MPNST) was based on clinical, radiological, and histological evidence. The tumor apparently originated in a spinal plexiform neurofibroma. The lesion was resected totally without neural damage to the sciatic nerve. However, the tumor recurred within 2 months. The patient died of unknown factors probably associated with the spinal involvement. MPNST associated with NF1 has a poor prognosis due to recurrence or metastasis despite complete macroscopic removal.

A 17-year-old female presented with a very rare case of primary Ewing's sarcoma of the skull involving the occipitotemporal region. Systemic examination found no evidence of metastasis. The tumor was surgically removed, and the patient underwent radiotherapy and chemotherapy. Fourteen months after surgery there has been no recurrence of the tumor. Cranial primary Ewing's tumor has a good prognosis after radical surgery and adjuvant therapy.