Toshihiko Kohno

Electron Microscope Study on Astrocytes in the Human Retina Using Ruthenium Red

The normal human retina treated either with ordinary or ruthenium-red-containing fixatives was studied with light and electron microscopes. Counts of the frequency of astrocytes using the light micros

Ocular Manifestations of Adult T-cell Leukemia/Lymphoma: A Clinicopathologic Study

BACKGROUNDnAdult T-cell leukemia/lymphoma (ATLL) is a recently described distinct clinicopathologic entity characterized by an extremely aggressive clinical course, a leukemic or lymphomatous proliferation of hyperlobulated peripheral T cells, and an association with infection by a retrovirus, human T-lymphotropic virus type I (HTLV-I). The authors present a patient with ATLL who initially had clinical features of severe uniocular intraocular inflammation, simulating acute retinal necrosis or herpetic retinitis, but results of histopathologic examination of the globe showed ATLL.nnnPATIENTnA 38-year-old man had severe unilateral intraocular inflammation associated with widespread diffuse retinitis. Two weeks later, a focal retinitis with vasculitis developed nasal to the optic disc in the opposite eye. Shortly thereafter, mental disturbance developed, and the patient died less than 3 months after onset of the ocular symptoms.nnnRESULTSnResults of postmortem examination showed atypical lymphocytic infiltration in the eyes, brain, and other systemic organs. Results of histopathologic and immunohistochemical studies showed that the atypical cells infiltrating the ocular tissues were ATLL cells.nnnCONCLUSIONSnPatients infected with HTLV-I initially can have intraocular T-cell lymphoma that simulates acute retinal necrosis or herpetic retinitis.

Peripheral Choriovitreal Neovascularization in Proliferative Diabetic Retinopathy: Histopathologic and Ultrastructural Study

We describe the histopathologic and ultrastructural evidence of choriovitreal neovascularization in the peripheral fundus of a non-vitrectomized eye with proliferative diabetic retinopathy (PDR). One eye with PDR was surgically enucleated because of neovascular glaucoma and studied with light and electron microscopy. The eye had neovascular membranes at the ora serrata of the peripheral fundus. The newly formed vessels originated from the choroid, passed through Bruch’s membrane and the retina, and extended into the vitreous. These vessels had either developing or mature characteristics. The endothelial cells of the developing vessels contained a bulky cytoplasm with many intracytoplasmic filaments, ribosomes and rough endoplasmic reticulum. Budding endothelial cells were frequently found in the developing vessels. The endothelial cells of the mature vessels had attenuated cytoplasm and fenestrations with diaphragms. These observations suggest that choriovitreal neovascularization in the peripheral fundus is one of the features of PDR.

The ultrastructure of parapapillary chorioretinal atrophy in eyes with secondary angle closure glaucoma

Abstract• Background: The present study was performed to investigate the ultrastructure of deep retinal layers and choroid corresponding to the parapapillary chorioretinal atrophy in eyes with secondary angle-closure glaucoma.• Methods: The glaucomatous eyes included two eyes enucleated due to iris ring melanoma with high intraocular pressure and one eye with neovascular glaucoma enucleated due to ocular pain. The control eyes included one eye enucleated due to choroidal malignant melanoma with normal intraocular pressure and one eye enucleated during surgery for supramandibular carcinoma. These eyes were studied with light and electron microscopy.• Results: In the region of parapapillary chorioretinal atrophy of glaucomatous eyes, the retinal pigment epithelial cells showed degenerative changes, such as loss of basal in foldings and microvilli, degenerated mitochondria, vacuolar degeneration and irregular distribution of melanin granules. The photoreceptors were decreased in number in this area of glaucomatous eyes. The lumen of the choriocapillary vessels adjacent to the optic nerve was collapsed.• Conclusion: These results elucidate the fine structures of deep retina and choroid in the region of parapapillary chorioretinal atrophy of glaucomatous eyes, and suggest that the reduced choroidal perfusion might be the pathogenetic mechanism of glaucomatous parapapillary chorioretinal atrophy.

A Case of Ocular Reticulum Cell Sarcoma Responded to Radiation Therapy

We report a case of reticulum cell sarcoma with involvement both in the brain and the eyes. The patient was a 49-year-old man. In 1985, he suffered steroid-resistant uveitis of unknown etiology in his right eye. After that, in 1986, he was aware of a weakness in the right arm and leg and of right sensory disturbances. Histopathological study of a biopsy specimen revealed a malignant lymphoma in the left thalamus, and the lesion was effectively treated by radiation to the brain. In 1987, he complained of visual disturbances in the left eye. According to the history and ocular manifestation, the disease was diagnosed as ocular reticulum cell sarcoma. Radiation therapy to his left orbital cavity was effective and inflammatory signs in the left eye subsided.