Biomedical subjects

C L Shields

Publications and source records attributed to C L Shields.

At least 253 records · Page 14Linked to original sources

PubMed1993

Hydroxyapatite orbital implant after enucleation--experience with 200 cases.

The recently introduced hydroxyapatite orbital implant was designed to provide improved motility of the prosthesis in patients who have undergone enucleation. To date, little has been written about the use of the hydroxyapatite orbital implant in eyes that harbored malignant neoplasms. We have performed hydroxyapatite orbital implantation in approximately 200 patients, including children as young as 1 month of age, who underwent enucleation primarily for malignant intraocular tumors. During a median follow-up of 24 months, no cases of orbital hemorrhage, orbital infection, implant extrusion, or implant migration have occurred. Three patients have had conjunctival erosion, which was successfully repaired. Motility of the socket and fornices has been excellent, and all patients have cosmetically satisfactory motility of the prosthesis. Use of the hydroxyapatite implant has had no adverse effect on the clinical course of the intraocular neoplasms, and it has not hindered postoperative evaluation for recurrent orbital tumor. Overall, the hydroxyapatite orbital implant seems to be well tolerated, provides improved motility of the prosthesis, and is associated with few complications.

Adult↗

PubMed1993

Current management of posterior uveal melanoma.

The management of malignant melanoma of the ciliary body and choroid (posterior uvea) is controversial. Authorities have disagreed about whether enucleation or conservative treatment offers the best prognosis. Although retrospective studies have suggested that the method of treatment makes no difference in the systemic prognosis, new studies in which the various therapeutic modalities are being compared are currently under way. The Collaborative Ocular Melanoma Study is attempting to address some of these issues in a randomized clinical trial. In this report, the currently available methods for managing posterior uveal melanoma are reviewed. Small asymptomatic choroidal melanomas can probably be observed periodically until evidence of growth is documented. Some small choroidal melanomas can be treated with laser photocoagulation. Alternatively, radiotherapy (either episcleral application of a radioactive plaque or charged particle irradiation) can be used. Although the two methods of radiotherapy seem equal relative to the development of systemic metastatic lesions, plaque radiotherapy is associated with fewer and less severe local complications. Selected melanomas of the ciliary body and peripheral choroid can be treated by local resection (partial lamellar sclerouvectomy). Local resection has theoretical advantages, but the surgical procedure is associated with potentially greater immediate complications. Enucleation is generally indicated for advanced melanomas that occupy most of the intraocular structures or have caused severe glaucoma. In addition, it is usually recommended for tumors that have invaded the optic nerve. The value of preenucleation radiotherapy in improving patient survival is unproved, although this technique seems reasonable in selected advanced tumors in which enucleation seems inevitable. Orbital exenteration is justified for advanced uveal melanomas with massive extraocular extension.(ABSTRACT TRUNCATED AT 250 WORDS)

Choroid Neoplasms↗

PubMed1993

Ocular tumors of childhood.

It is important for the pediatrician to be aware of the benign and malignant ophthalmic tumors that can occur in children. This article covers some general concepts related to ocular tumors in children and briefly describes the clinical features and management of some of the more important tumors of the eyelids, conjunctiva, intraocular structures, and orbit. Although most ocular tumors in children are benign, certain malignant neoplasms can threaten the child's life as well as the child's sight. Hence, prompt recognition and patient referral to an ocular oncologist are crucial for proper clinical management.

Child↗

PubMed1993

Fine-needle aspiration biopsy of suspected intraocular tumors. The 1992 Urwick Lecture.

BACKGROUND: Fine-needle aspiration biopsy recently has been used as a diagnostic modality for selected intraocular tumors and simulating conditions. However, the value of fine-needle aspiration biopsy for intraocular tumors previously has not been clarified. METHODS: Transocular fine-needle aspiration biopsy was performed on selected patients who had intraocular lesions that were suspected clinically to be neoplasms but in which there was diagnostic uncertainty based on noninvasive clinical evaluation. These cases were analyzed to determine accuracy, complications, and limitations of the technique. RESULTS: Of 6500 patients referred to the Oncology Service for evaluation of possible intraocular tumor, transocular fine-needle aspiration biopsy was used clinically in 159 cases (2.4%). It proved to be a reliable diagnostic method for intraocular malignancies such as uveal melanoma, uveal metastasis, retinoblastoma, lymphoma, and leukemia. In the 140 cases (88%) in which adequate cytologic material was obtained, the sensitivity rate was 100% and the specificity rate was 98%. In 19 cases where the cytologic material was too scant to render a diagnosis, the sensitivity rate was 84% and the specificity rate was 98%. The problem of insufficient material for cytologic diagnosis has been greatly minimized with the recent use of a 22-gauge needle. The main complication was localized intraocular hemorrhage. Retinal detachment and tumor recurrence have not been observed. CONCLUSIONS: Transocular fine-needle aspiration biopsy is a safe and reliable diagnostic method for suspected intraocular tumors and inflammatory conditions in which noninvasive diagnostic modalities have failed to establish the diagnosis and in which cytologic verification of the diagnosis is necessary to institute appropriate treatment. Although the authors have had few complications with fine-needle aspiration biopsy, the technique should be reserved for selected cases where the diagnosis has not been established by less-invasive diagnostic measures.

Anterior Eye Segment↗

PubMed1993

Phakomatous choristoma (Zimmerman's tumor). Immunohistochemical confirmation of lens-specific proteins.

BACKGROUND: Phakomatous choristoma is a rare, congenital, ocular adnexal tumor that is presumed to be of lenticular anlage based on light and electron microscopy. METHODS: The authors performed immunohistochemistry using standard commercially available antibodies against vimentin, S-100 protein, and several cytokeratins on a phakomatous choristoma that was excised from the right lower eyelid of a 10-week-old white boy. In addition, a battery of antibodies against lens-specific proteins, including alpha, beta, and gamma crystallins, was used. RESULTS: The tumor cells showed intense immunoreactivity for all lens-specific proteins tested. The epithelial cells of the phakomatous choristoma stained positively for S-100 protein and vimentin, the intermediate filament normally found in lens epithelial cells. Keratin markers were negative. CONCLUSIONS: The results of immunohistochemistry indicate that the cells of phakomatous choristoma synthesize several types of lens-specific proteins. Complementing previous light and electron microscopic studies, these data strongly support Zimmerman's conclusion that this pediatric adnexal tumor is a choristoma of lenticular anlage.

Antibodies, Monoclonal↗

PubMed1993

Histopathologic findings in congenital grouped pigmentation of the retina.

BACKGROUND: Congenital grouped pigmentation of the retina is a condition characterized by multiple, well-circumscribed, flat, pigmented fundus lesions clustered in a fashion resembling "bear tracks." METHODS: Light and electron microscopy was used to study these lesions in an eye of a 2-year-old boy. The eye was enucleated for retinoblastoma. RESULTS: Similar to the classic, solitary, congenital hypertrophy of the retinal pigment epithelium (CHRPE), the involved RPE cells contained an increased number of large pigment granules. Unlike CHRPE, most pigment granules retained the normal ellipsoidal shape. In addition, hypertrophy and hyperplasia of the RPE cells were not significant features by light and electron microscopy. CONCLUSION: Although the lesions in this case superficially resembled CHRPE by light microscopy, ultrastructural differences were identified.

Child, Preschool↗

PubMed1993

Plaque radiotherapy in the management of retinoblastoma. Use as a primary and secondary treatment.

BACKGROUND: Radioactive episcleral plaque brachytherapy is a treatment method for selected retinoblastomas. The authors have used this technique since 1976 as both a primary and a secondary treatment method after other methods failed to achieve tumor control. METHODS: A review of the records of 400 consecutive children with retinoblastoma showed that solitary plaque radiotherapy was used as a method of management in 103 cases. The authors' overall experience was evaluated, and the results between primary and secondary plaque therapies were compared in these 103 cases. RESULTS: Of the 103 tumors, the mean basal diameter was 7 mm, and the mean thickness was 4 mm. Overlying vitreous seeds were clinically apparent in 50 cases (48%). The mean proximity of the tumor margin to the optic disc margin was 6 mm and to the foveola was 6 mm. The mean follow-up period was 40 months. In 89 cases (86%), the tumor was controlled by one plaque application, whereas in 13 cases (13%), tumor recurrence after initial tumor shrinkage necessitated subsequent treatment. Final visual outcome was good in 63 cases (62%), poor in 30 (29%), enucleation in 9 (9%), and unknown in 1 case. The poor vision was due to foveal retinoblastoma (with or without amblyopia) in 25 cases (83%). Eight of the nine enucleated eyes were treated initially with external beam radiotherapy then later with plaque radiotherapy. In 31 cases (30%), plaque radiotherapy was used as a primary treatment to the tumor, while in 72 cases (70%), it was a secondary form of management after failure of other methods to control the tumor. Statistical analysis showed that tumors treated with plaque radiotherapy as a primary measure were more likely to be larger in in base (P = 0.01) and thickness (P = 0.01) than secondary treated tumors. The secondary treated retinoblastomas were more likely to have vitreous seeds (P = 0.02) than the primary treated tumors. The rate of tumor control and patient survival was similar between the two groups. CONCLUSION: Plaque radiotherapy is very effective in treating selected retinoblastomas with a high rate of tumor control and patient survival. It can be used successfully as a primary or a secondary treatment for tumors that have not been adequately controlled by other therapeutic methods.

Brachytherapy↗

PubMed1993

Conservative treatment of retinoblastoma. The use of plaque brachytherapy.

Retinoblastoma is the most common intraocular malignancy in childhood. The tumor arises from multipotential retinal cells. Treatment options include enucleation, external beam radiotherapy, episcleral plaque radiotherapy, photocoagulation, cryotherapy or a combination of these modalities. In retinoblastoma 10% have a positive family history and of the remaining 90%, 35% represent germinal chromosomal mutations while 65% represent somatic chromosomal mutations. Therefore, approximately 40% of all retinoblastomas are hereditary and are transmitted as a highly penetrant autosomal dominant trait. In the Wills Eye/Hahnemann University experience an analysis of 400 consecutive patients, 103 tumors in 103 eyes were treated with solitary plaque radiotherapy. Tumor regression was observed in all patients initially. After 40 months mean follow-up, persistent regression was observed in 89 cases (87%) and recurrences in 13 cases (13%). Of the 13 recurrences, five were in the group treated primarily (5/31) and eight in the group treated after failing other modalities (8/72). Plaque brachytherapy is an important tool in the management of retinoblastoma. Our preliminary data suggest that plaque brachytherapy is an effective treatment modality for primary treatment as well as after failure using other modalities.

Brachytherapy↗

PubMed1993

Massive orbital cyst of the lateral rectus muscle after retinal detachment surgery.

A 73-year-old white man presented with painless proptosis of the right eye 18 years after retinal detachment surgery on the same eye. Computed tomography (CT) showed a mass in the area of the lateral rectus muscle and magnetic resonance imaging (MRI) defined the multiloculated cystic mass to be located within the lateral rectus muscle. At the time of surgery, a large, thin-walled cystic lesion was found within the lateral rectus muscle. Histopathologically, the cystic mass was of nonkeratinizing stratified squamous conjunctival epithelium. Massive orbital cysts after retinal detachment surgery are rare. The authors review the literature and comment on the differential diagnosis and presumed pathogenesis of this lesion.

Aged↗

PubMed1993

Massive precorneal extension of squamous cell carcinoma of the conjunctiva.

A 73-year-old man had only light perception vision from a slowly enlarging fleshy papillomatous mass covering the entire cornea. The lesion was excised completely, leaving a clear corneal bed and 20/25 vision. Histopathologically, the lesion was found to be squamous cell carcinoma in situ with early microinvasion of the basement membrane. Viral studies for human papilloma virus were negative. This case represents a massive superficial involvement of the cornea by squamous cell carcinoma and shows the resistance of Bowman's membrane to tumor penetration.

Aged↗

PubMed1993