Ultrastructure and pathogenesis of intracranial arachnoid cysts.

A detailed light, transmission, and scanning electron microscopic study of the arachnoid cyst wall was made in four cases and compared with that of the normal arachnoid mater in the human. Two hundred and eight reported cases of arachnoid cysts were analyzed to evaluate the anatomical distribution of these lesions and to get r an insight into their pathogenesis. The structural features of the arachnoid cyst wall that distinguish it from the normal arachnoid membrane are as follows: (1) splitting of the arachnoid membrane at the margin of the cyst, (2) a very thick layer of collagen in the cyst wall, (3) the absence of traversing trabecular processes within the cyst, and (4) the presence of hyperplastic arachnoid cells in the cyst wall, which presumably participate in collagen synthesis. The distribution of arachnoid cysts in two hundred and eight reported cases was as follows: Sylvian fissure, 49%; cerebellopontine angle, 11%; supracollicular area, 10%; the vermis, 9%; sellar and suprasellar area, 9%; interhemispheric fissure, 5%; cerebral convexity, 4%; and the clival and interpeduncular area, 3%. At each site, except possibly on the cerebral convexity, the cyst was associated with a normal subarachnoid cistern. This striking and nearly invariable association of arachnoid cysts with normal subarachnoid cisterns prompts the authors to hypothesize that arachnoid cysts represent a congenital anomaly of the developing subarachnoid cisterns in early intrauterine life. It is postulated that, during the process of the complex folding of the primitive neural tube and the formation of normal subarachnoid cisterns, an anomalous splitting of the arachnoid membrane occurs.

Immunoelectron microscopy for growth hormone and prolactin in pituitary adenomas.

Growth hormone (GH)- and prolactin (Prl)-producing pituitary adenomas were studied with immunoelectron microscopy using protein A-gold complex, and were compared with the normal pituitary gland. GH-producing cells were readily identifiable by numerous, uniformly dense, round secretory granules in both adenomas and normal pituitary gland. In contrast, Prl secretory granules in normal pituitary gland were much larger in size than the scarce, smaller, secretory granules of Prl-producing adenomas. Thus immunoelectron microscopic identification of Prl is more valuable for prolactinoma. With more specific antigens available as tumor markers, immunoelectron microscopy appears to be a powerful tool for tumor diagnosis.

Primary pulmonary rhabdomyosarcoma: a case report and review of the literature.

Although several primary pulmonary neoplasms containing striated muscle fibers have in the past been described as rhabdomyoma or rhabdomyosarcoma, it was not until 1939 that McDonald and Heather described the first acceptable case of this neoplasm. Since then 13 such cases have been reported in the world literature. Previously reported cases of the neoplasm are reviewed and the salient features described. The origin of the striated muscle fibers has been much debated. Some believe that they develop from myoblastic differentiation of primitive mesenchymal cells or metaplastic transformation of pleuripotential mesenchymal cells present in the bronchial walls and pulmonary interstitium, whereas others claim that they develop from misplaced striated muscle tissue from the pharyngeal or esophageal region. A case report of the pleomorphic type of primary pulmonary rhabdomyosarcoma with multiple hematogenous metastases is presented as well as a review of the literature with a discussion of the histogenesis.

Nosocomial Hemophilus influenzae type C meningitis in an adult.

Hemophilus influenzae type C meningitis developed in a 68-yr-old man with a cerebrospinal fluid leak which occurred after craniotomy for an olfactory groove meningioma. Hemophilus influenzae is an uncommon cause of meningitis in adults, and most reported cases have been due to type B or nontypeable strains.

Haemophilus paraphrophilus brain abscess.

The clinical course of a patient with brain abscess due to Haemophilus paraphrophilus is described. The organism was recovered in pure culture from purulent material collected at surgery. The role of this organism as a human pathogen is reviewed.

Transdiaphragmatic ventriculoperitoneal shunting: technical case report.

OBJECTIVE AND IMPORTANCE: This report describes an important technical modification in ventriculoperitoneal shunting. CLINICAL PRESENTATION: A young woman presented with shunt malfunction caused by occlusion of the peritoneal catheter. Conventional sites for placement of distal catheter were unavailable or had been used up. INTERVENTION: After the installation of a ventriculopleural shunt resulted in pleural effusion, it was converted to a transdiaphragmatic ventriculoperitoneal shunt, resulting in an excellent clinical outcome. CONCLUSION: The suprahepatic subdiaphragmatic space can be directly accessed in some selected patients with extensive peritoneal adhesions, resulting in successful ventriculoperitoneal shunting.

The history of spinal biomechanics.

The history of spinal biomechanics has its origins in antiquity. The Edwin Smith surgical papyrus, an Egyptian document written in the 17th century BC, described the difference between cervical sprain, fracture, and fracture-dislocation. By the time of Hippocrates (4th century BC), physical means such as traction or local pressure were being used to correct spinal deformities but the treatments were based on only a rudimentary knowledge of spinal biomechanics. The Renaissance produced the first serious attempts at understanding spinal biomechanics. Leonardo da Vinci (1452-1519) accurately described the anatomy of the spine and was perhaps the first to investigate spinal stability. The first comprehensive treatise on biomechanics, De Motu Animalium, was published by Giovanni Borelli in 1680, and it contained the first analysis of weight bearing by the spine. In this regard, Borelli can be considered the "Father of Spinal Biomechanics." By the end of the 19th century, the basic biomechanical concepts of spinal alignment and immobilization were well entrenched as therapies for spinal cord injury. Further anatomic delineation of spinal stability was sparked by the anatomic analyses of judicial hangings by Wood-Jones in 1913. By the 1960s, a two-column model of the spine was proposed by Holdsworth. The modern concept of Denis' three-column model of the spine is supported by more sophisticated testing of cadaver spines in modern biomechanical laboratories. The modern explosion of spinal instrumentation stems from a deeper understanding of the load-bearing structures of the spinal column.

Subdural hematomas of arterial origin.

Three cases of acute subdural hematoma related to bleeding aneurysm or arteriovenous malformation are presented. Various possible arterial sources of bleeding that may lead to subdural hematoma are reviewed. The complex cause and effect relationship between the presence of aneurysm or arteriovenous malformation and the occurrence of subdural hematoma in a head-injured patient is discussed. The pitfalls of reliance on the computed tomogram as a sole diagnostic test in the evaluation of head-injured patients or of unconscious patients with no available history are emphasized.

Ivory osteoma of the cervical spine: case report.

OBJECTIVE AND IMPORTANCE: We report a unique case of ivory osteoma of the cervical spine. CLINICAL PRESENTATION: The clinical presentation was one of polyradicular deficit without myelopathy after trauma. The imaging characteristics and histology of the lesion were those of a classic ivory osteoma. INTERVENTION: A complete surgical excision of the lesion was accomplished. CONCLUSION: We think we have recorded the only well-documented case of ivory osteoma affecting the spine.

Primary pontine hematoma presenting as a cerebellopontine angle mass.

A case of hemipontine hematoma from the rupture of a cryptic vascular malformation presenting as a cerebellopontine angle tumor is reported. The clinical features of and surgical approaches to partial pontine hematomas are briefly reviewed.

The sinking bullet.

We report a case of a missile injury to the brain with an unusual complication. The bullet migrated by its mere weight to a distant location through the brain parenchyma after it initially lodged in a superficial site. Instances of similar phenomena reported in the literature are reviewed.

Lipofibromatous hamartoma of the median nerve: case report with magnetic resonance imaging correlation.

The authors report a case of lipofibromatous hamartoma of the median nerve in a patient who presented with symptoms of carpal tunnel syndrome. The diagnosis was made by magnetic resonance imaging and confirmed by intraoperative findings and histological diagnosis; distinctive magnetic resonance imaging features of this entity are described. In this patient, surgery was limited to biopsy to confirm the diagnosis and external neural decompression, which helped to stop the progression of the symptoms. In their review of the literature, the authors found four types of lipomatous masses in the extremities affecting the function of peripheral nerves, commonly the median nerve. Treatment and the extent of surgery differ for each patient, based on the anatomical findings and extent of neurological deficit. The etiology, pathogenesis, differential diagnosis, and surgical management of lipofibromatous hamartoma are described.

Craniocephalic disproportion with increased intracranial pressure and brain herniation: a new clinical syndrome in anemic patients: report of two cases.

OBJECTIVE AND IMPORTANCE: We describe a new clinical syndrome in two patients with chronic anemia. The major manifestation of the syndrome is herniation of the brain resulting in death caused by longstanding craniocephalic disproportion. The disproportion was caused by extreme thickening of the cranium because of erythroid hyperplasia. CLINICAL PRESENTATION: Two patients with known chronic anemia presented with chronic increase in intracranial pressure with acute deterioration resulting in brain herniation. INTERVENTION: Despite maximum medical therapy, both patients died as a result of uncontrollable increase in intracranial pressure. CONCLUSION: Patients with chronic anemia presenting with progressive headaches should be monitored for this newly described clinical phenomenon.

Effect of glycerol on peripheral nerve: an experimental study.

Håkanson's method of treatment of trigeminal neuralgia by injecting glycerol into the trigeminal cistern is being used in a few clinical centers with encouraging results. We undertook this experimental study utilizing a rat sciatic nerve model to elucidate the mode of action of glycerol. Fifty-six rats were divided into three groups. The topical application of pure glycerol on the sciatic nerve was used in Group I. The intraneural injection of glycerol was used in Group II. The effect of graded concentrations of glycerol was studied in Group III. Physiological saline was the control in Groups I and II. The animals were killed at the end of either 1 or 3 1/2 weeks after the application of glycerol, and the sciatic nerves were examined with light and electron microscopy. Our results show that myelin disintegration and axonolysis occur with glycerol application. Myelinated and unmyelinated fibers are affected at random, although the most striking histological changes were seen in the myelinated fibers.

Neurosurgical and immunological implications of primary cerebral amyloid (congophilic) angiopathy.

Two cases of histologically documented primary cerebral amyloid complicated by spontaneous intracerebral hematoma are reported. The neurosurgical implications of this disease are reviewed briefly. Immunological studies in one patient, believed to be a rare survivor of an intracerebral hemorrhage from nonfamilial primary cerebral amyloid angiopathy, demonstrated an increased percentage of B cells within both the cerebrospinal fluid (CSF) and the blood compartments. Hypofunction of CSF concanavalin A-activated suppressor cells with respect to B and T cell targets was shown. The blood suppressor cells from the patient were similar to those of an age-matched control. Compartmental central nervous system suppressor cell dysfunction resulting in B cell activation could play a role in facilitating amyloid deposits in the brain. The mechanisms responsible for the compartmental and limited suppressor cell dysfunction are unknown.

Extradural ecchordosis physaliphora of the thoracic spine: case report.

OBJECTIVE AND IMPORTANCE: We report an unusual case of ecchordosis physaliphora of the thoracic spine. CLINICAL PRESENTATION: The clinical presentation was one of disabling thoracic radicular pain without objective neurological deficit. The imaging characteristics of the lesion were those of a cyst containing aqueous fluid. There was no bone destruction. INTERVENTION: Gross total removal of the lesion was accomplished. CONCLUSION: We present the only well-documented case of thoracic extradural ecchordosis physaliphora and discuss the relationship between the notochord, ecchordosis physaliphora, and chordoma. We provide a comprehensive list of lesions exhibiting physaliphorous cells.

Suprascapular entrapment neuropathy: a clinical, anatomical, and comparative study. Part 3: comparative study.

The suprascapular ligament seems to serve no defined function in the human. A comparative study was undertaken to elucidate its function. The suprascapular region was dissected in species representing seven existing primate families and six subprimate families. A striking dichotomy of pattern was observed. In the New World primates, the suprascapular ligament appeared to be continuous with the coracoclavicular ligament; the former merely served to increase the area of bony attachment of the coracoclavicular ligament. In the Old World monkeys and subprimate mammals, the suprascapular ligament was entirely absent. The human anatomy was comparable to that found in the New World primates. This dichotomy of pattern seems to be related to the function of the upper extremity in the different classes of mammals.

Structural changes in human pituitary tumor after bromocriptine therapy.

The histological appearance of a prolactin-producing tumor and of a growth hormone-producing tumor after short term bromocriptine therapy was studied in detail using light microscopy with conventional and immunocytochemical methods and using transmission electron microscopy. The findings were correlated with clinical, radiological, and biochemical data. Histological changes consisting of clumping of nuclear chromatin and a marked reduction in cytoplasmic volume due to loss of ribosomes, rough endoplasmic reticulum, and Golgi complexes were observed only in the prolactin-producing tumor. Normalization of elevated serum prolactin levels and reduction in size of the tumor observed in serial computed tomograms correlated with striking histological changes found in the tumor. These changes were interpreted to represent a reversible inhibition of the protein-synthetic machinery of the neoplastic cell. Comparable clinical, biochemical, radiological, or structural changes were not observed in the growth hormone-secreting tumor.

Spinal arterial aneurysm: case report.

Isolated aneurysms of the spinal artery (not associated with arteriovenous malformations) are exceptionally rare. Fewer than 17 cases have been reported in the literature. We report a case of an isolated spinal artery aneurysm causing acute subarachnoid hemorrhage. Spinal artery aneurysms are contrasted with the more common intracranial aneurysms in terms of presentation and pathogenesis. The various clinical presentations of spinal artery aneurysms are discussed as well. A summary of all reported cases of spinal aneurysms, with and without associated arteriovenous malformations, is listed.

Occult intrasacral meningocele: clinical and radiographic diagnosis.

We evaluated four patients who had occult intrasacral meningocele with multimodality radiographic imaging techniques. The clinical features, radiological findings, gross appearances of the lesion at surgery, surgical technique, histopathological features of the cyst wall, and surgical outcome are described. The role of magnetic resonance imaging in the preoperative evaluation compared with standard radiographic techniques is discussed. Theories regarding the pathogenesis of this lesion are reviewed.