Extracranial aneurysm of the posterior inferior cerebellar artery.

Aneurysms of the posterior inferior cerebellar artery (PICA) are rare, and may arise in unusual locations due to the complex and variable anatomy of this artery. The PICA does not usually originate from the extracranial vertebral artery. Of the few reported extracranial PICA aneurysms, all affected the distal segment. We describe an unusual extracranial PICA-vertebral artery (VA) junction aneurysm.

The role of exudation in chronic subdural hematomas.

OBJECT: Chronic subdural hematomas (SDHs) are a local inflammatory process that causes the formation of a granulation tissue often referred to as the external or outer membrane. This membrane has abnormally permeable macrocapillaries. Therefore, exudation from the macrocapillaries in the outer membrane of chronic SDH may play an important role in the enlargement of chronic SDH. In this study the authors investigated the role of exudation in chronic SDH. METHODS: The authors examined 24 patients (16 men and eight women; age range 38-86 years [mean age 61.4 years]) with 27 chronic SDHs. The clinical status of the patients was evaluated according to the classification described by Markwalder. The diagnosis was established on computed tomography (CT) scans in all cases. The authors also used the Nomura Classification for judging the lesion's appearance on CT scans. Immediately after the diagnosis, all patients were administered 20 mCi (740 mBq) technetium-99m human serum albumin. Four hours later, blood and SDH samples were taken and radioactivity levels were measured in each. The ratio of activity of the samples taken from chronic SDH to the radioactivity of blood was determined as a percentage and defined as the exudation rate. On the follow-up CT scan obtained on postoperative Day 20, subdural collections thicker than 5 mm were determined to be a reaccumulation. RESULTS: The correlations between the exudation rate and age of the patients, clinical grades, CT appearances, and amount of reaccumulation were investigated. In this series the average exudation rate was 13.24% (range 2.05-28.88%). The mean exudation rates according to the clinical grades assigned to patients were as follows: Grade 0, 8.67 +/- 5.64% (three patients); Grade 1, 5.07 +/- 1.43% (eight patients); Grade 2, 17.87 +/- 3.73% (seven patients); and Grade 3, 19.65 +/- 7.67% (six patients). Exudation rates in patients with Grades 2 and 3 were significantly higher than those in Grades 0 and 1 (p < 0.05). The mean exudation rates according to the lesion's appearance on CT scans were found as follows: hypodense appearance, 6.55 +/- 4.52% (eight patients); isodense appearance, 11.07 +/- 6.32% (five patients); hyperdense appearance, 19.47 +/- 13.61% (three patients); and mixed-density appearance, 17.40 +/- 5.80% (nine patients). The differences among the groups were significant (p < 0.05). The average exudation rate was statistically higher in the patients with reaccumulation (16.30 +/- 8.16%) than that in the patients without reaccumulation (9.96 +/- 6.84%) (p < 0.05). CONCLUSIONS: The exudation rate in chronic SDH is correlated with a higher clinical grade (Markwalder Grade 2 or 3), mixed-density CT appearance, and reaccumulation. Therefore, exudation from macrocapillaries in the outer membrane of chronic SDH probably plays an important role in the pathophysiology and the growth of chronic SDH.

Primary solitary cervical amyloidosis: case report and review of the literature.

STUDY DESIGN: A case report and literature review are presented. OBJECTIVE: To describe and review the clinical presentations, characteristic findings from imaging studies, types, differential diagnosis, prognosis, and treatment of amyloidoma arising within the vertebrae. SUMMARY OF BACKGROUND DATA: Amyloidoma can occur in the bone, skin, larynx, lymph nodes, urinary bladder, eye, tongue, and gastrointestinal system. However, amyloidomas affecting the vertebral bones are very rare. To our knowledge, only 3 cases of amyloidoma involving cervical spine have been reported previously. METHODS: In this report, we present a case of solitary amyloidosis of the cervical spine. RESULTS: The differential diagnosis of primary solitary spinal amyloidoma includes metastasis, infection, primary bone tumors, plasmocytoma, and Potts abscess. The correct diagnosis can be achieved only after the specific staining of tissue. The prognosis of amyloidosis is related to the specific form of amyloidosis. However, primary solitary amyloidosis has the best prognosis, although a limited number of patients without long-term follow-up studies have been reported. CONCLUSIONS: Primary solitary amyloidosis is a rare form of the amyloidosis, which is different from the other forms of amyloidosis because of excellent prognosis with surgical excision. Combined surgical excision and spinal stabilization is the best treatment.

Cerebellopontine angle lipoma with extracranial extension.

Lipomas of the cerebellopontine angle (CPA) are rare. A recent literature review identified only 98 reported cases of CPA lipoma. We present here a case of CPA lipoma in a 28-year-old woman who was admitted to our hospital with hearing loss in her left ear. Computed tomography scan and magnetic resonance imaging revealed a CPA mass lesion with extracranial extension around the left internal carotiol artery. The patient was operated on in the sitting position via a right suboccipital craniectomy. The intracranial part of the mass was partially removed. Histopathological examination resulted in a diagnosis of lipoma. Surgical treatment of CPA lipomas is rarely indicated, and the aim of surgery must be decompression of neural structures.

Primary meningioma of the paranasal sinus.

We report a 17 year old man with a primary ectopic meningioma in the right ethmoid and maxillary sinus. He underwent endoscopic surgery. After total removal of the tumour his subsequent clinical course was good. The clinical and pathologic features of the 32 previously reported cases in the literature are also reviewed. The pathogenesis and treatment of primary paranasal sinus meningioma is briefly discussed.

Recurrent solitary fibrous tumour in the cerebellopontine angle.

Solitary fibrous tumours (SFT) of the central nervous system are rare. They resemble meningioma in clinical presentation, imaging features and appearance at surgery. Schwannoma, hemangiopericytoma and other spindle cell mesenchymal neoplasms should also be considered in the differential diagnosis. Although the histogenesis of this tumour is still debated, strong CD34 reactivity of the tumour cells suggests that SFT is mesenchymal. We present the clinical, radiological, and pathological features of an SFT located in the cerebellopontine angle (CPA). A 55-year-old female presented with 6 months of headache. The MRI scan showed a contrast enhancing ovoid mass in the left CPA. At craniotomy, the tumour was completely resected. Histolopathological diagnosis was of meningioma. Three years later, the symptoms recurred and an MRI scan demonstrated tumour recurrence. A repeat craniotomy was performed and the lesion was again completely excised. Tumour morphology on histopathology and immunoreactivity for CD34 of the tumour cells supported the diagnosis of SFT. Review of the original tumour also disclosed immunoreactivity for CD34. Ki67 labeling indices were less than 1% in both tumours.

Intradiploic epidermoid cysts of the skull: a report of four cases.

Epidermoid cysts are uncommon, benign and slow-growing lesions. They may often reach an enormous size without producing neurological symptoms. Intradiploic epidermoid cysts are nearly 25% of all epidermoids. They are derived from ectodermal remnants that stay within the cranial bones during embryonic development. Intradiploic epidermoid cysts can be located in any part of the skull. Two of our four cases were located in left occipital bone and the others were in the frontal bone. These tumours can occur at any age from the first to the seventh decade of life. Our cases had a mean age of 38.75 years (19-55 years). They may reach great sizes before the initial diagnosis and may produce major neurological signs. For good long-term prognosis, correct radiological assessment and complete removal of the tumour with its capsule are essential. We report four cases of intradiploic epidermoid cysts of the skull and analyse the clinical, radiological features and treatment of these lesions in the light of relevant literature.

Intracranial falcine and convexity chondromas: two case reports.

Intracranial chondromas are uncommon intracranial tumours that most frequently arise from the skull base. They can, however, arise from the calvarium or the meninges. In these cases their neuroradiological features may mimic other intracranial tumours. We present two cases of intracranial chondroma, one that originated from the convexity and the other from the falx. Total excision was achieved in both cases. The literature on intracranial chondromas is reviewed.

Malignant triton tumor of the lumbar spine.

STUDY DESIGN: A case report of surgically treated malignant triton tumor of the L2 nerve root. OBJECTIVES: To discuss treatment methods of the rare malignant triton tumor. SUMMARY OF BACKGROUND DATA: Malignant peripheral nerve sheath tumors are neoplasms that most often arise in peripheral nerves or in neurofibromas. Malignant triton tumor is a histologic variant of those tumors. METHODS: A 58-years-old male patient was admitted with severe back and leg pain. Magnetic resonance imaging revealed a dumbbell-shaped tumor over the right L2 nerve root. The tumor mass was removed posteriorly and the spine was stabilized by transpedicular screws followed by radiation therapy. RESULTS: The tumor was diagnosed as "malignant triton tumor." There was no sign of metastasis during the 8 months of follow up. CONCLUSIONS: In this case, the diagnosis of triton tumor is based solely on microscopic evidence of the neural tissue accompanied by rhabdomyoblasts and immunohistochemical examination. Patients with malignant triton tumors are usually younger than age 35. Our patient is 1 of the oldest patients with tumor occurrence in the spinal canal. Although our patient still has no evidence of recurrence, the prognosis is poor for this group of patients.