Biomedical subjects

R L Font

Publications and source records attributed to R L Font.

At least 127 records · Page 7Linked to original sources

PubMed1986

Rapid diagnosis of Acanthamoeba keratitis using calcofluor white.

Calcofluor white (CFW) is a chemofluorescent dye with an affinity for the polysaccharide polymers of amebic cysts. Using CFW staining with fluorescent microscopy, we demonstrated amebic cysts in corneal scrapings and keratectomy specimens from four patients with culture-proved Acanthamoeba keratitis and from one in whom CFW was the only positive laboratory test. Calcofluor white staining is simple, rapid, and highly reliable in the diagnosis of Acanthamoeba keratitis.

Adolescent↗

PubMed1986

Apocrine hidrocystomas of the lids, hypodontia, palmar-plantar hyperkeratosis, and onychodystrophy. A new variant of ectodermal dysplasia.

A fourth case of a newly recognized variant of ectodermal dysplasia is reported. This syndrome is characterized by bilateral apocrine hidrocystomas of the eyelid margins, hypodontia, palmar-plantar hyperkeratosis, and onychodystrophy. To our knowledge, this syndrome, with its striking ocular manifestations, has not been previously documented in the ophthalmic literature.

Aged↗

PubMed1986

The autoimmune nature of aqueous tear deficiency.

Twenty-two patients with aqueous tear deficiency (ATD) were examined for the presence of the following autoantibodies: immunofluorescent antinuclear antibody (ANA) and Sjögren's syndrome antibodies A and B (SS-A and SS-B). These autoantibodies were found in 17 (82%) patients but not in control subjects, and they correlated with the severity of symptoms and ocular surface changes. Bacterial keratitis, often recurrent and bilateral, and progressive sterile corneal stromal melting developed in six autoantibody-positive ATD patients. Eight antibody-positive patients had labial salivary or lacrimal gland biopsies, and all showed similar histologic features with marked destruction of the glandular architecture by lymphocytic infiltration. Immunoglobulin and complement were not detected in the glandular tissue. Circumstantial evidence suggests that an abnormal immunologic reaction, possibly related to Epstein-Barr viral (EBV) infection, is the cause of the glandular destruction and tear deficiency.

Autoantibodies↗

PubMed1986

Corneal blood staining. An animal model.

Corneal blood staining was established in the rabbit cornea by injecting autologous, citrate-buffered blood in the anterior chamber. Increased intraocular pressure was maintained above 30 mm of Hg by self-sealing trans-limbal injections repeated every 12 hours. Typically, corneal edema developed in 3 days, followed several days later by a red discoloration that turned brown about 2 days later. Histopathologically, the edematous cornea disclosed endothelial swelling and attenuation with marked stromal edema. Histochemically, the red-stained cornea disclosed only extracellular hemoglobin particles; the brown-stained corneas showed extracellular and intracellular hemoglobin particles as well as intracellular hemosiderin in keratocytes. Spectrophotometric analysis of the keratectomy specimens suggested the presence of porphyrins in all stages of blood staining, including the edematous cornea. Oxyhemoglobin was found in red-stained corneas, while methemoglobin was present in the brown-stained corneas. It was concluded that endothelial degeneration uniformly accompanied corneal blood staining in this model and that keratocytes are actively involved in hemoglobin degradation.

Animals↗

PubMed1985

Intravenous pyogenic granuloma of the ocular adnexa. Report of two cases and review of the literature.

Intravenous pyogenic granuloma is a recently described form of pyogenic granuloma (PG) in which the angiomatous proliferation is confined entirely within the lumen of a vein. To our knowledge, only four cases involving the ocular adnexa, including two that we encountered, have been described. Histologically, this benign lesion is similar to PG of other locations and is characterized by lobular congeries of capillaries embedded in a fibromyxoid matrix containing scattered chronic inflammatory cells. The whole lesion appears as a single polypoid mass projecting into the lumen of a dilated vein. The histogenesis of this lesion remains obscure. Complete local excision is the treatment of choice. Intravenous PG can be differentiated from other intravascular fibroangiomatous proliferations, including intravascular papillary endothelial hyperplasia, intravenous atypical vascular proliferation, intravascular fasciitis, and organized thrombus.

Adult↗

PubMed1985

Large cell lymphoma of the orbit with microvillous projections ('porcupine lymphoma').

A 57-year-old man had a diffuse mass in the lacrimal gland area associated with extensive bony destruction. A malignant epithelial tumor of the lacrimal gland was suspected clinically, and a biopsy specimen disclosed an undifferentiated malignant neoplasm of uncertain origin. Ultrastructural studies, however, revealed features of a lymphoid tumor with myriad cytoplasmic microvillous projections. The patient has had no evidence of systemic lymphoma after more than three years of follow-up. To our knowledge, this is the first report of orbital involvement of a large cell lymphoma with microvillous projections ("porcupine lymphoma"). The role of electron microscopy in the differential diagnosis of this orbital tumor was important, since epithelial tumors of the lacrimal gland are best managed by surgical excision, whereas lymphoid tumors usually respond satisfactorily to radiotherapy.

Biopsy↗

PubMed1985

Pigmented free-floating vitreous cysts in two young adults. Electron microscopic observations.

Pigmented free-floating vitreous cysts were observed in two young adults. In both patients, the cyst was in the visual axis; however, the size and extent of pigmentation of the cyst wall compromised the visual acuity only in case 1. In this case, the vitreous cyst was aspirated through the pars plana and studied by light and electron microscopy. Histopathologically, the cyst was lined by a heavily pigmented layer of cuboidal cells intermixed with sheets of nonpigmented cells forming papillae. Ultrastructurally, the pigmented cells contained predominantly large, mature melanosomes (0.9-2.2 micron). Scattered immature melanosomes with a scarcity of mitochondria and other cytoplasmic organelles were present. Additionally, the cells were invested by a thin polarized basement membrane and displayed apical microvilli. Numerous microvillous processes were noted under the plasmalemmae and between adjacent cells. The results of the light and ultrastructural studies provide support for the hypothesis that the cyst in case 1 originated from the pigment epithelium. The possibility of a traumatic etiology is proposed for these pigmented vitreous cysts. If significant visual impairment is present, surgical removal of the cyst through a pars plana approach can be safely performed as in our case 1.

Adult↗

PubMed1985

Immunohistochemical demonstration of neuronal and astrocytic differentiation in retinoblastoma.

Sections of 51 surgically enucleated eyes from cases of retinoblastomas were examined immunohistochemically to delineate patterns of cellular differentiation. Employing the avidin-biotin immunoperoxidase technique, antibodies were used against glial fibrillary acidic protein (GFAP), S-100 protein and neuron specific enolase (NSE). Areas of uninvolved retina and/or optic nerve were used as built-in positive control. Most of the tumors showed GFAP and S-100 protein-positive perivascular glial cells that were interpreted as reactive astrocytes. In three well-differentiated retinoblastomas, glial cells were found to be interspersed randomly among tumor cells and not associated with blood vessels. These glial cells were interpreted as neoplastic based on their distribution pattern and cytologic features. In about half of the tumors, the retinoblastoma cells stained positively for NSE, indicating their neuronal tumor cells that stained positively for NSE but failed to show any evidence of photoreceptor differentiation. Based on these observations and similar differentiation patterns described in other primitive neuroectodermal tumors of the brain, it is suggested that retinoblastoma cells can differentiate not only into photoreceptor cells but also along other neuronal cell lines and rarely into glial cells.

Astrocytes↗

PubMed1985

Sympathetic ophthalmia. An immunohistochemical study of epithelioid and giant cells.

There is controversy regarding the origin of the pigment-containing epithelioid cells in the uvea of eyes with sympathetic ophthalmia. The results of the present immunocytochemical study demonstrating the presence of muramidase and S-100 protein in these cells, and the binding of peanut lectin by the pigment-containing cells support the interpretation that the pigment-containing epithelioid cells and giant cells are of monocytic (histiocytic) origin. Our study also emphasizes the diverse functional capacity of these epithelioid cells.

Epithelium↗

PubMed1985

Acute monocytic leukemia recurring as bilateral perilimbal infiltrates. Immunohistochemical and ultrastructural confirmation.

A 28-year-old woman developed leukopenia and slight cervical lymphadenopathy. Bone marrow aspiration and special stains established the diagnosis of acute monocytic leukemia. Following chemotherapy a complete hematologic remission was elicited. Seven months later, she consulted an ophthalmologist because of bilateral conjunctival lesions. Ophthalmologic examination showed subconjunctival, perilimbal grayish-pink infiltrates. A conjunctival biopsy disclosed sheets of mononuclear cells consistent with acute monocytic leukemia. Four months later, she developed cutaneous lesions in the face and chest wall. Subsequent biopsies of conjunctiva and skin and immunohistochemical demonstration of muramidase in the tumor cells supported the diagnosis of monocytic leukemia. Electron microscopic studies were particularly valuable and disclosed that more than 80% of the leukemic cells contained two types of cytoplasmic complexes of rough endoplasmic reticulum that displayed both tubular and helical configurations. These complexes differed morphologically from the ribosome-lamellar complexes observed in hairy cell leukemia and other hematologic disorders.

Adult↗

PubMed1985

Spontaneous intrastromal iris cyst. A case report with immunohistochemical and ultrastructural observations.

A 39-year-old man had an enlarging intrastromal iris cyst that obstructed the chamber angle inferotemporally and abutted the cornea. No history of ocular trauma or previous surgery was present. Iridocyclectomy with en bloc resection of the cyst was performed. The cyst was lined by one to three cell layers of focally pigmented epithelium that ultrastructurally exhibited desmosomes, tonofilaments, terminal bars, and apical microvilli. Additionally, membrane-bound melanin granules (melanosomal complexes) consistent with phagocytized uveal melanin granules were observed. Immunohistochemistry confirmed intracellular keratin. We conclude that the non-traumatic cyst reported herein is of surface ectodermal origin and suggest that such cysts be removed en bloc by sector iridectomy or iridocyclectomy if the lesion has been proven to enlarge.

Adult↗

PubMed1985

Foveomacular vitelliform dystrophy, adult type. A clinicopathologic study including electron microscopic observations.

Foveomacular vitelliform dystrophy, adult type (FVDAT), is a dystrophy of the retinal pigment epithelium (RPE) characterized in part by autosomal dominant inheritance, midlife onset, mild visual loss, and various patterns of foveal yellow deposits located at the level of the pigment epithelium. Detailed pathologic studies of two postmortem eyes from a 61-year-old woman with documented FVDAT disclosed striking abnormalities involving mainly the foveal RPE and overlying photoreceptors. By light microscopy, marked focal atrophy of the pigment epithelial cells in the foveolar area was bordered by hypertrophic RPE. Interposed between the atrophic RPE and Bruch's membrane were scattered eosinophilic, fusiform collagenous plaques. The sensory retina overlying the deranged RPE displayed marked atrophy of the outer nuclear layer with loss of photoreceptor inner and outer segments. Pigment-laden macrophages containing periodic acid-Schiff-positive material had migrated into the atrophic, outer sensory retina. Ultraviolet fluorescent microscopy demonstrated massive accumulation of lipofuscin pigment within the macular RPE as well as within macrophages in the atrophic outer retina. By scanning electron microscopy, a confluent area of flattened, atrophic retinal pigment epithelial cells was rimmed by taller, hypertrophic RPE cells. By transmission electron microscopy, the pigment epithelial cells contained myriad lipofuscin granules. Bruch's membrane and the intercapillary pillars were slightly thickened and the choriocapillaris was patent. The possible interrelationships between FVDAT and the other pattern dystrophies of the RPE are discussed.

Female↗

PubMed1985

Granulocytic sarcoma of the orbit. A clinicopathologic study.

A 9-year-old Latin American girl developed proptosis of the left eye associated with pain in the left ear of one month's duration. Ophthalmoscopic examination of the left eye disclosed retinal striae with venous tortuosity and papilledema. CT scan of the orbit showed a nonenhancing, irregular intraconal mass. CT scan of the brain demonstrated an enhancing left temporoparietal mass. Craniotomy revealed a 7 cm, extra-axial mass that was attached to the dura mater. Histologic examination, including a positive Leder stain, established the diagnosis of granulocytic sarcoma. At that time, the results of the laboratory studies, including complete cell blood count, were normal. Periodic clinical and hematologic evaluation was recommended. Twenty-five days after craniotomy, examination of the peripheral blood disclosed 56% myeloblasts and the bone marrow contained 30% blast cells. The problem in histologic differential diagnosis and a review of the literature is discussed.

Child↗

PubMed1985

Hemangiopericytoma of the meninges of the optic nerve. A clinicopathologic report including electron microscopic observations.

A 61-year-old man complained of visual loss of his right eye following a systemic viral illness. At this time, complete ophthalmologic examination failed to disclose any abnormalities. Over the next months the patient developed dramatic loss of vision. Extensive workup, including CT scans, failed to clarify the underlying cause and a diagnosis of optic atropy following optic neuritis was made. The patient remained asymptomatic, but repeated CT scans depicted a fusiform enlargement of the intraorbital portion of the right optic nerve, three years after the onset of visual loss. The presumptive clinical diagnosis was optic nerve meningioma and the tumor was removed via a Krönlein procedure. Histopathologically, a highly vascularized intradural mass that led to compression atrophy of the optic nerve was present. The tumor was composed of fascicles of spindle-shaped cells that were interspersed among numerous, irregular vascular channels. Electron microscopically, the cells disclosed a lucent cytoplasm with a scarcity of organelles, prominent cytoplasmic filaments, numerous micropinocytotic vesicles and subplasmalemmal linear densities (hemidesmosomes). Poorly developed intercellular junctions were present between interdigitating cytoplasmic processes. The tumor cells surrounding the vascular units displayed a continuous basement membrane as well as all the features of well-differentiated pericytes. Away from vascular structures some tumor cells, which showed a focally discontinuous basement membrane, exhibited intermediate features between pericytes and fibroblasts. To the best of our knowledge, this is the first report of a hemangiopericytoma arising from the meninges of the optic nerve.

Cranial Nerve Neoplasms↗

PubMed1985

Malignant peripheral nerve sheath tumors of the orbit: a clinicopathologic study of eight cases.

Eight adult patients with malignant peripheral nerve sheath tumors of the orbit are described. Only two of the patients were known to have von Recklinghausen's neurofibromatosis. The typical clinical history included the development of a mass in the superonasal quadrant of the orbit, which was palpable immediately beneath the skin of the lid. There was a definite tendency for the lesions to arise in, or grow along, the supraorbital nerve--including posteriorly through the superior orbital fissure to the Gasserian ganglion, and even as far posteriorly along the trigeminal rootlets to the pons. Delays in pathologic diagnosis, which beclouded the true nature of the process, led to multiple recurrences, eventuating in five known fatalities out of the eight patients. In addition to intracranial extension, pulmonary metastases and regional cervical metastases were encountered. Once recognized for their diagnostic value, the histopathologic patterns are highly distinctive: biphasic populations of spindled and epithelioid cells; sheets of epithelioid cells or clusters demarcated by delicate reticulin fibers or thicker collagenous trabeculae; malignant plexiform patterns; and neurotubular patterns. Pure spindle cell populations were encountered only in the two patients with von Recklinghausen's disease, and in each, either a pre-existent benign neurofibroma or a coexistent plexiform neurofibroma was found in the pathology specimens. The best management of this condition depends upon early clinical and pathological recognition, leading to radical surgery, which usually consists of orbital exenteration combined with intracranial extirpation of as much of the trigeminal nerve as possible. Postoperative radiotherapy and chemotherapy after radical surgery might also be advisable.

Adult↗

PubMed1984

Cavernous hemangioma of the retina. Immunohistochemical and ultrastructural observations.

A 6-month old girl had unilateral leukokoria. Because retinoblastoma could not be excluded, the blind left eye was enucleated. Histopathologically, a total retinal detachment associated with a widespread cavernous hemangioma of the retina and a preretinal membrane were found. The specimen was further examined by immunohistochemistry and electron microscopy to determine the origin of the preretinal membrane and to study the anatomy of the telangiectatic retinal vessels. The preretinal membrane was mostly composed of spindle-shaped cells that demonstrated immunohistochemically the presence of glial fibrillary-acidic protein and showed, ultrastructurally, numerous glial filaments in their cytoplasm. These findings support the view that this membrane was of glial origin. By electron microscopy, the telangiectatic retinal vessels displayed the anatomic features normally encountered in retinal vessels, which accounts for the absence of exudates observed clinically and angiographically in cases of cavernous hemangioma of the retina.

Astrocytes↗

PubMed1984

Glioneuroma of iris and ciliary body.

A 20-year-old woman was noted to have progressive cataractous changes in the left eye for two years. Ophthalmic examination showed a yellow-pink mass in the iris root (between the 8- to 10- o'clock positions, facing the patient). No associated colobomatous defect was present. A sector iridectomy with partial cyclectomy was performed. Histopathologically the mass, which was composed of an admixture of glial cells and neurons, was diagnosed as glioneuroma. It was believed the tumor had been incompletely excised at the posterior margin of surgical resection. No additional therapy was instituted. When the patient was reexamined 6 1/2 years later, the residual mass remained unchanged. Four previously reported cases of glioneuromas of the iris and ciliary body are summarized.

Adult↗

PubMed1984

Acanthamoeba keratitis possibly acquired from a hot tub.

An irritated left eye followed by a geographic epithelial corneal defect developed in a 42-year-old man. Disciform edema developed in the cornea, and the lesion progressed to a ring-shaped abscess. The lesion failed to respond to medical therapy. After two penetrating keratoplasties, histopathologic examination and electron microscopic studies established the diagnosis of Acanthamoeba keratitis. Subsequent cultures and immunofluorescent studies identified the organism as Acanthamoeba castellani. Following treatment with antibiotics and corneal cryotherapy, there has been no evidence of recurrence. Morphologically and immunologically identical amebae were also cultured from the patient's hot tub and surrounding garden.

Adult↗