Biomedical subjects

Robert J Kowalski

Publications and source records attributed to Robert J Kowalski.

4 recordsLinked to original sources

PubMed2004

Pituicytoma.

Pituicytoma is a rare, low-grade neoplasm that originates in the neurohypophysis of the pituitary gland. We report the clinicopathologic features of a pituicytoma arising in a 52-year-old man who presented with a mass and panhypopituitarism, clinically suggestive of a pituitary adenoma. The tumor was marked by a proliferation of elongated cells arranged in bundles and interlacing fascicles. The tumor demonstrated positive staining with S-100 protein and glial fibrillary acid protein antibodies. The tumor did not stain with antibodies to cytokeratin, synaptophysin, chromogranin, anterior pituitary hormones, or p53. An MIB-1 labeling index of 1.1% was observed. The tumor was subtotally resected and recurred 11 months after the initial surgery. The literature on this rare tumor will be reviewed and differential diagnosis discussed.

Biomarkers, Tumor↗

PubMed2003

Biomechanics of spinal deformity.

The correction of spinal deformity may be achieved by a variety of methods, each of which has advantages and disadvantages. The goals of spinal deformity surgery include reasonable correction of the curvature, prevention of further deformation, improvement of sagittal and coronal balance, optimization of cosmetic issues, and restoration/preservation of function. The failure to consider all these factors appropriately may result in a suboptimal outcome. Understanding fundamental biomechanical principles involved in the formation, progression, and treatment of spinal deformities is essential in the clinical decision-making process.

Anthropometry↗

PubMed2002

Clinical features of third ventriculostomy failures classified by fenestration patency.

BACKGROUND: To evaluate strategies for treating endoscopic third ventriculostomy (ETV) failure, we assessed patients, clinical features at failure, and the outcome of VP shunt placement at re-operation, classifying patients by fenestration patency. METHODS: Thirty-six patients with failed ETV were evaluated retrospectively. All but 4 had cine phase-contrast magnetic resonance (MR) images at re-operation to determine whether the fenestration was patent, and were grouped into "patent" and "no flow" groups. Symptoms at re-operation, the interval to failure, and outcome of re-operation were compared between these groups. RESULTS: Progression of elevated intracranial pressure (ICP) signs was significantly more frequent in the "no flow" group than the "patent" group (p = 0.0025). The median interval to failure was 2.5 months, with no statistical difference between the "patent" group (median 4.0 months) and the "no flow" group (median 1.1 months). Re-operations consisted of 29 shunt placements, 4 redo ETVs, and 3 combinations of both. Kaplan-Meier estimation indicates that 41% of shunts would be expected to fail by 5.2 years. The success rate of shunt placement was somewhat worse in the "no flow" group, although the difference was not statistically significant (p = 0.066). Four patients in the "patent" group treated with shunt placements eventually became shunt-independent with continuously patent fenestration; these were considered delayed successes. CONCLUSION: Patients with signs of elevated ICP and "no flow" findings on MR should be given emergency treatment because they have a high risk of symptom progression. The clinical differences between "patent" and "no flow" fenestration at re-operation after ETV failure are considered to be worthy of further study.

Adolescent↗

PubMed2002

Skull base neurocytoma: case report and review of the literature of extraventricular neurocytomas.

We report a rare skull base neurocytoma. A 44-year-old female with a history of focal seizure and progressive right-sided weakness sought treatment at an outside institution, where she underwent total resection of a "left medial sphenoid wing paraganglioma" in 1984. In 1995 after experiencing intense left-sided headaches for 3 weeks, the patient presented to our institution. Magnetic resonance imaging revealed a large local recurrence. She had deficits dating to her initial surgery, including moderate right-sided hemiparesis, complete left ophthalmoplegia, and left facial numbness.The patient underwent a craniotomy with extensive removal of the involved sphenoid bone and a subtotal resection of the tumor. Neurocytoma was diagnosed based on strong immunohistochemical staining for synaptophysin and no reactivity for glial fibrillary acidic protein. Postoperatively, her headaches resolved completely and her neurologic status remained at baseline. The residual tumor was treated with radiation therapy. After 5 years, she remains clinically and radiographically stable.Although typically located adjacent to the foramen of Monro, neurocytomas have now been reported in almost every subcompartment of the craniospinal axis. Finding neurocytomas in extraventricular locations may require revisiting the current theory that subependymal progenitor cells are the cells of origin for these tumors.

Case Reports↗