Retrobulbar Region Research Articles

The impact of 99mTc-DTPA orbital SPECT in patient selection for external radiation therapy in Graves’ ophthalmopathy

In Graves' ophthalmopathy (GO), there is a demand to differentiate the immunologically active disease state, when immunosuppressive therapy is necessary, from the inactive state, when the patient would not benefit from it. We measured the inflammatory activity in the retrobulbar region using Tc-diethylene triamine pentaacetic acid (DTPA) SPECT before and after external radiation to determine whether this method is suitable for predicting the effectiveness of this therapy. Thirty-two patients with suspected active GO were involved in this retrospective study. The initial image, DTPA uptake value (UV) and its change after therapy were assessed to monitor the effect of the therapy and investigate whether a pretreatment scan is capable of predicting the outcome. Depending on the change in DTPA UV after radiotherapy, three patient groups were formed: decreased, increased or minimally changed (less than 1×10 injected dose (ID)/ml). The initial DTPA UVs of these groups were significantly different (P<0.001). Improvement was observed mainly in patients with higher initial values. When comparing the groups with low (<12×10 ID/ml) versus high (≥12×10 ID/ml) initial uptake, an unexpected increase was observed in the first group after therapy (mean: +2.89±2.66×10 ID/ml), whereas the average change in the DTPA UV was negative in the latter group as anticipated (-2.24±4.47×10 ID/ml, P<0.00001). We found that in GO patients a high DTPA UV may predict the response to orbital radiation therapy. DTPA orbital SPECT may be a suitable technique for the selection of GO patients for radiation therapy.

The distribution and expression of claudin-5 and occludin at the rat blood–optic nerve barrier after borneol treatment

The purpose of this study is to investigate the distribution and expression of the tight junction membrane proteins, claudin-5 and occludin, in rat blood-optic nerve barrier after borneol treatment. Seventy-two female Wistar rats were randomly divided into the borneol gastric lavage group and the equal volume solvent gastric lavage control group. The bilateral optic nerve from the retrobulbar region to the optic chiasma was collected from the rats in the two groups before gastric lavage and at 30 min, 1, 2, 4, and 8 h after gastric lavage. The distribution and expression of claudin-5 and occludin were detected using immunofluorescence staining, Western blotting, and reverse transcription polymerase chain reaction (RT-PCR). Results showed that claudin-5 translocated from the cell membrane to the cytoplasm at 30 min following initiation of borneol treatment, and this translocation peaked at 1 h. During this period of time, a small amount of occludin also translocated from the cell membrane to the cytoplasm. Four hours after initiation of treatment, claudin-5 and occludin levels in the cytoplasm began to decrease and were restored to their normal pattern 8 h after initiation of treatment. There were no significant differences in the levels of claudin-5 or occludin before or after treatment in either group. It was concluded that claudin-5 and occludin translocate within cells of the rat blood-optic nerve barrier after borneol treatment, and this translocation was reversible. Claudin-5 may play a potential role in permeability of the blood-optic nerve barrier following borneol treatment.

Influence of retrobulbar neuritis and papillitis on echographically measured optic nerve diameter

Retrobulbar (optic) neuritis is inflammation of the optic nerve that may cause a complete or partial loss of vision. This inflammation can affect a part of the nerve within the eyeball (neuropapillitis) or a part of the nerve behind the eyeball (retrobulbar neuritis). The aim of this study was to establish whether there is a correlation between the diameter of a retrobulbar part of the optic nerve and either visual acuity, prominence of the optic disk (papillitis), or nature of the neuritis (papillitis or retrobulbar). We tested 23 patients with retrobulbar neuritis and papillitis. In addition to a complete ophthalmologic examination, the diameter of retrobulbar region of the optic nerve was measured by the B-scan method. Following this, the 30-degree test was carried out. We found an increased thickness of the retrobulbar region in 22 patients and different responses to the 30-degree test, as well as a statistically significant negative correlation between the thickness of retrobulbar part of the optic nerve and visual acuity. The retrobulbar part of the optic nerve is thicker in 94% of the patients with retrobulbar neuritis and in all the patients with papillitis. There is a correlation between the reduction of visual acuity and thickening of a retrobulbar part.

The presence and distribution of elastin in the posterior and retrobulbar regions of the mouse eye

The Presence and distribution of elastin in the posterior and retrobulbar regions of the mouse eye was investigated. Mice of two strains (C57/BL6 and DBA/2J) were studied at 2 months and 8–12 months of age. Light, confocal, and transmission electron microscopy were used to identify elastin, using immunohistochemical techniques and ultrastructural evaluation. Elastin was found in the following ocular structures: conjunctiva, muscle tendons, sclera, choroid, and meninges. The elastin in the sclera was most dense in a ring surrounding the peripapillary optic nerve head, with its presence in the inner sclera declining with greater distance from the nerve head. Elastin fibers were oriented in the sclera along what would be expected to be the principal stress directions generated from the intraocular pressure, though actual biomechanical measurements have not yet been made in the mouse sclera. Elastin comprises a portion of the mouse sclera and its distribution in the peripapillary area is similar to that in human eyes.

O.092 Benign intracranial hypertension: Experience from a single centre

To evaluate morphologic changes occurring in the retrobulbar region after optic nerve sheath decompression (ONSD) in patients with idiopathic intracranial hypertension using magnetic resonance (MR) imaging.Prospective observational study.This study included 26 eyes of 17 patients (age range, nine to 57 years) with idiopathic intracranial hypertension who underwent ONSD. The surgery was performed through transconjunctival medial orbitotomy and by a dural window excision. After ONSD, the optic nerves were examined with MR imaging by means of 3-dimensional “constructive interference in steady state” (CISS) sequence.After ONSD, papilledema resolved in all eyes and visual functions improved in all except one. Early postoperative MR imaging (two to eight weeks after surgery) demonstrated a cyst-like fluid collection adjacent to the dural window site in nine (75%) of 12 eyes and a fibrous tissue formation in three eyes (25%). Late postoperative MR imaging (six to 15 months after surgery) demonstrated a fibrous tissue formation at the decompression site in 25 eyes (96%) and perioptic fluid collection in one eye (4%).In early postoperative period after ONSD, a fluid collection adjacent to the decompression site occurs in most eyes; this finding disappears in late period. Early postoperative MR findings support the idea that ONSD functions through the cerebrospinal fluid (CSF) filtration.

Impact of hyaluronidase on anesthetic distribution in retrobulbar region following sub-Tenon anesthesia

Sub-Tenon's block is nowadays commonly used in ophthalmic surgery because of its safety and efficacy. The aim of this study was to investigate the distribution of the anaesthetic solution with different amounts of hyaluronidase in the retrobulbar space, following an injection into the Sub-Tenon's space. In this experimental study, 40 pig cadaver heads were used (80 eyeballs). The material was divided into four groups (of 20 eyeballs each). Each group was administered 4.5 ml of a mixture of 2% lignocaine, 0.5% bupivacaine, and 0.5 ml of Indian ink, with different amounts of hyaluronidase--15 IU/ml, 75 IU/ml, 150 IU/ml, except the control one. Samples of retrobulbar tissue were analysed using the standard histopathological procedure. After that, they were also analysed using the Adobe Photoshop program (Windows, USA). The retrobulbar space was divided into eight zones by four perpendicular lines, which crossed in the centre of the optic nerve. The presence of ink in fat and muscle tissues and in the sheath of the optic nerve was observed. The presence of the local anaesthetic solution was significantly higher in inferonasal and superonasal quadrants of the fat and muscle tissues (p < 0.01). The distribution in optic nerve sheath is similar in each quadrant. Distribution of local anesthetic in each zone of the muscle tissue (I-VIII) was strongly influenced by the amount of hyaluronidase added. In the fat tissue, the distribution of local anesthetic under the influence of hyaluronidase was significantly higher (p < 0.05) in the areas which were distant from the place of injection (I-IV). The distribution in the optic nerve sheath is significantly higher (p < 0.01) in the group with 150 IU/ml of hyaluronidase. Following a sub-Tenon block local anaesthetic was present in the retrobulbar space in a high percentage of the cases. The presence of local anaesthetic solution in retrobulbar space depends on the amount of hyaluronidase previously added to the local anaesthetic.

Tonic Pupil as the Presenting Sign of Relapsed Acute Myeloid Leukemia

A 23-year-old woman complained of photophobia, lacrimation, and redness of the left eye of 1 week's duration and a dilated left pupil. Acute myeloid leukemia (AML) had been diagnosed 5 years earlier and treated with a stem cell transplant. She had developed graft vs host disease (GVHD) affecting her skin and had undergone psoralen plus UVA (PUVA) treatment. The AML had been in remission for 3 years before her ophthalmic visit. Medications included acyclovir, fluconazole, penicillin, cyclosporine, and mycophenolate. Systemic corticosteroid treatment had recently been discontinued. Best-corrected visual acuities were 20/20 in the right eye and 20/40 in the left eye, improving to 20/30 with pinhole. In the left eye, the palpebral fissure was slightly narrow but with normal levator function, the tear break-up time was reduced, and there was punctate staining of the cornea. The pupils measured 2 mm in the right eye and 4 mm in the left eye in minimal illumination. On bright light stimulation with the indirect ophthalmoscope light, the right pupil constricted to 1 mm and the left remained at 4 mm. After stimulation by a near target the left pupil also constricted to 1 mm. The left eye showed vermiform movements of the iris on slit lamp examination. Dilute pilocarpine (0.125%) was then instilled in both eyes. After this both pupils measured 2 mm, demonstrating hypersensitivity of the left pupil. She was orthophoric and had a full range of ocular movements. Posterior subcapsular lens opacities were present in both eyes. Ophthalmoscopy was normal. The punctuate epitheliopathy of the cornea was attributed to GVHD and the cataracts to the use of systemic corticosteroids. Left tonic pupil was diagnosed. Lubricants were prescribed for the epitheliopathy. Two days later, she returned complaining of blurred vision. Best-corrected visual acuities were 20/80 in the right eye and 20/40 in the left eye. There was no change in the anterior segment findings of either eye. Ophthalmoscopy showed localized elevation of the retina in the macular region in both eyes. B scan ultrasound showed thickening and irregular elevations of the choroid in both eyes (Fig. 1). Fluorescein angiography showed pinpoint areas of hyperfluorescence of increasing brightness in the macular region of both eyes.FIG. 1: B scan ultrasound of the left eye shows thickening and irregularity of the choroid (arrowhead) and overlying serous retinal detachment.Blood tests showed an elevated white cell count, indicating relapse of leukemia. Brain and orbit MRI showed only faint mucosal thickening of the sinuses. Chemotherapy was begun. The leukemia could not be controlled, and she subsequently died of systemic complications. Tonic pupil can be caused by Adie syndrome, systemic neuropathic diseases, or local lesions (1). Adie syndrome is characterized by tonic pupil and disturbance of deep tendon reflexes without evidence of local ocular or orbital disease or generalized peripheral or autonomic system dysfunction. Orbito-ocular causes of tonic pupil include inflammation, infection, or infiltration that affects ciliary ganglion or the ciliary nerves in the retrobulbar region or in the suprachoroidal space. Tonic pupil has been reported in siderosis caused by retained intraocular foreign body (2); injury to the final cholinergic fibers within the suprachoroidal space was postulated as the likely pathologic mechanism. Postganglionic denervation by damage within the suprachoroidal space has also been reported with retinal detachment surgery using explants (3) and after laser photocoagulation for diabetic retinopathy (4). Leukemia can cause tonic pupil by direct infiltration of the orbit or the choroid. However, postganglionic nerve injury at the level of the eye in choroidal cancer has been reported only once (5). In our patient, there was no imaging evidence of orbital infiltration at presentation. The ultrasound study showed extensive choroidal thickening and irregularity. The fluorescein evidence of pinpoint leaks and serous retinal detachment indirectly indicated dysfunction of the retinal pigment epithelium. A similar phenomenon caused by choroidal infiltration has been reported (6). Hence it is likely that the damage to the ciliary nerves occurred at the suprachoroidal level. Mandagere R. Vishwanath, FRCSEd Stephen J. Charles, MA, MD, FRCOphth Manchester Royal Eye Hospital Manchester, United Kingdom [email protected]

Findings of Magnetic Resonance Imaging after Optic Nerve Sheath Decompression in Patients with Idiopathic Intracranial Hypertension

To evaluate morphologic changes occurring in the retrobulbar region after optic nerve sheath decompression (ONSD) in patients with idiopathic intracranial hypertension using magnetic resonance (MR) imaging. Prospective observational study. This study included 26 eyes of 17 patients (age range, nine to 57 years) with idiopathic intracranial hypertension who underwent ONSD. The surgery was performed through transconjunctival medial orbitotomy and by a dural window excision. After ONSD, the optic nerves were examined with MR imaging by means of 3-dimensional "constructive interference in steady state" (CISS) sequence. After ONSD, papilledema resolved in all eyes and visual functions improved in all except one. Early postoperative MR imaging (two to eight weeks after surgery) demonstrated a cyst-like fluid collection adjacent to the dural window site in nine (75%) of 12 eyes and a fibrous tissue formation in three eyes (25%). Late postoperative MR imaging (six to 15 months after surgery) demonstrated a fibrous tissue formation at the decompression site in 25 eyes (96%) and perioptic fluid collection in one eye (4%). In early postoperative period after ONSD, a fluid collection adjacent to the decompression site occurs in most eyes; this finding disappears in late period. Early postoperative MR findings support the idea that ONSD functions through the cerebrospinal fluid (CSF) filtration.

Retro-Orbital Metastasis From Breast Cancer: An Uncommon Site!

We report the case of a 65 year old lady who presented with symptomatic retro-bulbar metastasis from breast cancer at first presentation. This was diagnosed on CT of the orbit and confirmed on biopsy. She was also found to have widespread metastatic disease elsewhere and had systemic treatment in the form of cytotoxic chemotherapy to which the tumour showed a good response. There are only a handful of cases of orbital metastases in the literature, and of these, retro-bulbar tumours are even rarer. There is no report to date of simultaneous presentation of breast primary and symptomatic secondary in the retrobulbar region.

MULTIMODALITY IMAGE FUSION TO FACILITATE ANATOMIC LOCALIZATION OF 99MTC‐PERTECHNETATE UPTAKE IN THE FELINE HEAD

99mTc-pertechnetate is excreted in humans by the thyroid glands, gastric mucosa, salivary glands, choroid plexus, and sweat glands. Uptake attributed to the zygomatic and molar salivary glands is used commonly as a reference to assess thyroid uptake and differentiate euthyroid from hyperthyroid cats. However, the exact location and origin of uptake of 99mTc-pertechnetate in the head during thyroid scintigraphy in cats remains uncertain. The purpose of this study was to localize uptake of 99mTc-pertechnetate in the head of the cat using multimodality image fusion. Computed tomography (CT), magnetic resonance (MR), and single photon emission tomography (SPECT) imaging were performed successively in two cats during the same anesthesia procedure. Transverse, dorsal, and sagittal images were reconstructed for each modality. Images were rescaled and fused manually. The anatomic location of focal 99mTc activity in SPECT images was identified in CT and MR images. Four major and four minor focal areas of uptakes were identified in the head in both cats. A rostral conical-shaped activity was identified in the nasal cavity. Two symmetric focal areas of uptakes seen in the soft tissues in the ventro-caudal retro-bulbar region, and rostro-medial to the vertical ramus of the mandible were attributed to zygomatic salivary glands. A central focal activity located ventral and caudal to the zygomatic uptake was located in the nasopharynx and soft palate. Minor symmetric areas of uptake identified in the retromandibular region were attributed to parotid and mandibular salivary glands. Minor symmetric areas of uptake identified in the region of the mandible were attributed to molar salivary glands. No focal area of uptake was identified in the brain.

Bifurcating Axons Account for the Increase in Axonal Population in Posterior Human Optic Nerve

Purpose: To demonstrate the presence of axonal bifurcation in the human optic nerve implicated by morphometric analysis. Methods: Six human optic nerves were visualized directly using light and electron microscopy. Results: Under the light microscope, features suggestive of bifurcating axons were found in about one in four 1-μ m-thick sections examined (or about one bifurcating axon per 0.024 mm3 of tissue). This amounted to about 18,750 bifurcations throughout the course of the human optic nerve. In most cases, the bifurcating axons branched off from the long axis of the main axon at an orthogonal angle before turning in 2–5 microns to continue coursing posteriorly. Ultrastructural analysis confirmed the axonal bifurcations observed with light microscopy. Conclusions: Axonal bifurcation in the human optic nerve is partly responsible for the increased axonal area and contributes to the increased optic nerve diameter as the nerve courses back from retrobulbar region to the pre-chiasmatic area. The present study adds bifurcating axons to the body of evidence supporting parallel processing in man since branching axons allow a single retinal ganglion cell to carry visual information to different nuclei in the central nervous system.

Optic Nerve Size and Constituent Components: Posterior Is More

Purpose: To divide the human optic nerve into its constituent fractions and describe the relative contributions of each as the nerve increases in diameter as it courses back from its retrobulbar origin towards the optic chiasm. Methods: Seven human optic nerves were examined via a semiautomatic, computer-assisted morphometric analysis system. Results: The cross-sectional area, the axonal area, and the axonal population of the pre-chiasmic region relative to the retrobulbar region of the nerve increased by 45.2%, 35.4%, and 17.1%, respectively (p values: 0.044, 0.049, and 0.03, respectively). The other constituents in the nerve, namely myelin and the extra-axonal matrix, showed increases of 48.6% and 44.6%, respectively (p values: 0.016 and 0.094, respectively) in the posterior portion. Conclusions: Nearly equivalent increases in the three main constituents of the human optic nerve (axons, myelin, and extra-axonal matrix) are responsible for the increase in diameter of the human optic nerve as it courses posteriorly from the retrobulbar area towards the optic chiasm.

Orbital Hemangiopericytoma — A Case Report

Abstract A 50-year-old male presented with progressive proptosis in the right eye for 10 years. Decreased visual acuity to hand-motion level was also noted. Orbital computed tomography revealed a large homogenously enhanced mass lesion in the right retrobulbar region with optic nerve compression. The remainder of the ocular examination was normal, except for right mature cataract. The tumor was completely removed through lateral orbitotomy. Histologic findings showed a picture of hemangiopericytoma. One month after cataract extraction and intraocular lens implantation in the right eye, the patient had restored vision. Through 2 years' follow-up, no more orbital tumor was noted. Orbital hemangiopericytoma may have potentially malignant behavior, and a high local recurrence rate if incompletely excised. Complete, intact removal prevents tumor recurrence and provides a good result.

Long-term results of irradiation for patients with progressive GRAVES’ ophthalmopathy

Purpose: To determine the long-term outcome of radiotherapy (RT) in patients with progressively symptomatic thyroid eye disease and to evaluate the potential long-term sequelae.Methods and Materials: Four hundred fifty-three patients provided written informed consent and received retrobulbar RT for Graves’ ophthalmopathy at Stanford University Medical Center; 197 with ≥1 year of follow-up were retrospectively analyzed. Of the 197 patients, 189 received RT to the bilateral retrobulbar regions, and 4 received unilateral RT. The technical information was unavailable for 4 patients. Patients were assessed by chart review, telephone interview, questionnaire, and multidisciplinary physician examination. Eye impairment was scored using the SPECS system. The end point review included the before and after treatment SPECS score, surgical intervention, and patient satisfaction. Potential complications, including cataract development, retinopathy, and tumor formation, were investigated. Multivariate analyses were performed to assess the prognostic variables.Results: Improvement or resolution was 89% for soft-tissue findings; 70% for proptosis; 85% for extraocular muscle dysfunction; 96% for corneal abnormalities; and 67% for sight loss. The response to RT may take >6 months to stabilize. Factors predictive of response varied in the individual SPECS categories but included the initial SPECS score, pretreatment thyroid status, female gender, a 20-Gy RT dose, and a history of hypertension. Nonpredictive factors included a history of tobacco use, diabetes mellitus, steroids, and prior cataracts. Only 16% required surgical intervention to preserve their vision or restore binocular vision. Twenty-two patients (12%) developed cataracts after irradiation (median 11 years). No patient developed a tumor within the RT field during the follow-up period (range 1–29 years). Ninety-eight percent of patients were pleased with their results, and 2% believed their symptoms progressed despite RT.Conclusions: Retrobulbar irradiation (20 Gy) is safe and effective treatment for progressive Graves’ ophthalmopathy, with a 96% overall response rate, 98% patient satisfaction rate, and no irreparable long-term sequelae, with follow-up extending 29 years. The most common late effect observed was cataract development, which occurred more frequently in older patients and was reversible with extraction. Elective surgical intervention after RT should be withheld until patients have demonstrated a plateau in response.

Dynamic 3D computer-assisted reconstruction of a metallic retrobulbar foreign body for diagnostic and surgical purposes. [Case report of orbital injury with ethmoid bone involvement

The main goal of our dynamic 3D computer-assisted reconstruction of a metallic retrobulbar foreign body following orbital injury with ethmoid bone involvement was to use 3D-information obtained from standard computed tomography (CT) data to explore and evaluate the nasal cavity, ethmoidal sinuses, retrobulbar region, and the foreign body itself by simulated dynamic computed visualization of the human head. A foreign body, 10 × 30 mm in size, partially protruded into the posterior ethmoidal cells and partially into the orbit, causing dislocation and compression of the medial rectus muscle and inferior rectus muscle. The other muscles and the optic nerve were intact. Various steps were taken to further the ultimate diagnosis and surgery. Thin CT sections of the nasal cavity, orbit and paranasal sinuses were made on a conventional CT device at a regional medical center, CT scans were transmitted via a computer network to different locations, and special views very similar to those seen on standard endoscopy were created. Special software for 3D modeling, specially designed and modified for 3D C-FESS purposes, was used, as well as a 3D-digitizer connected to the computer and multimedia navigation through the computer during 3D C-FESS. Our approach achieves the visualization of very delicate anatomical structures within the orbit in unconventional (non-standard) sections and angles of viewing, which cannot be obtained by standard endoscopy or 2D CT scanning. Finally, virtual endoscopy (VE) or a ‘computed journey’ through the anatomical spaces of the paranasal sinuses and orbit substantially improves the 3D C-FESS procedure by simulating the surgical procedure prior to real surgery.

Olfactory bulb and retrobulbar regions in the hedgehog tenrec: Organization and interconnections

Olfactory bulb and retrobulbar regions in the hedgehog tenrec: Organization and interconnections

Distribution of choline acetyltransferase immunoreactivity in the brain of an elasmobranch, the lesser spotted dogfish (Scyliorhinus canicula).

Although the distribution of cholinergic cells is remarkably similar across the vertebrate species, no data are available on more primitive species, such as cartilaginous fishes. To extend the evolutionary analysis of the cholinergic systems, we studied the distribution of cholinergic neurons in the brain and rostral spinal cord of Scyliorhinus canicula by immunocytochemistry using an antibody against the enzyme choline acetyltransferase (ChAT). Western blot analysis of brain extracts of dogfish, sturgeon, trout, and rat showed that this antibody recognized similar bands in the four species. Putative cholinergic neurons were observed in most brain regions, including the telencephalon, diencephalon, cerebellum, and brainstem. In the retrobulbar region and superficial dorsal pallium of the telencephalon, numerous small pallial cells were ChAT-like immunoreactive. In addition, tufted cells of the olfactory bulb and some cells in the lateral pallium showed faint immunoreactivity. In the preoptic-hypothalamic region, ChAT-immunoreactive (ChAT-ir) cells were found in the preoptic nucleus, the vascular organ of the terminal lamina, and a small population in the caudal tuber. In the epithalamus, the pineal photoreceptors were intensely positive. Many cells of the habenula were faintly ChAT-ir, but the neuropil of the interpeduncular nucleus showed intense ChAT immunoreactivity. In the pretectal region, ChAT-ir cells were observed only in the superficial pretectal nucleus. In the brainstem, the somatomotor and branchiomotor nuclei, the octavolateral efferent nucleus, and a cell group just rostral to the Edinger-Westphal (EW) nucleus contained ChAT-ir neurons. In addition, the trigeminal mesencephalic nucleus, the nucleus G of the isthmus, some locus coeruleus cells, and some cell populations of the vestibular nuclei and of the electroreceptive nucleus of the octavolateral region exhibited ChAT immunoreactivity. In the reticular areas of the brainstem, the nucleus of the medial longitudinal fascicle, many reticular neurons of the rhombencephalon, and cells of the nucleus of the lateral funiculus were immunoreactive to this antibody. In the cerebellum, Golgi cells of the granule cell layer and some cells of the cerebellar nucleus were also ChAT-ir. In the rostral spinal cord, ChAT immunoreactivity was observed in cells of the motor column, the dorsal horn, the marginal nucleus (a putative stretch-receptor organ), and in interstitial cells of the ventral funiculus. These results demonstrate for the first time that cholinergic neurons are distributed widely in the central nervous system of elasmobranchs and that their cholinergic systems have evolved several characteristics that are unique to this group.

Olfactory bulb and retrobulbar regions in the hedgehog tenrec: Organization and interconnections

The Madagascan lesser hedgehog tenrec (Echinops telfairi) is a terrestrial, nocturnal insectivore with a low encephalization index and a huge olfactory bulb. To gain insight into the organization and evolution of olfactory regions in placental mammals, the cytoarchitecture (Nissl), neurochemical attributes [zinc and acetylcholinesterase stain, nicotinamide adenine dinucleotide phosphate (NADPh)-diaphorase, and calcium-binding proteins], and interconnections (injections of wheat germ agglutinin-horseradish peroxidase and biotinylated dextran amine) of tenrec bulbar and retrobulbar regions were examined. The tenrec has a well-laminated main olfactory bulb, and modified (atypical) glomeruli are found that, to date, have been demonstrated only in murine rodents. Compared with the main olfactory bulb, the accessory bulb is relatively small, with clearly different staining characteristics, particularly with respect to NADPh-diaphorase, anticalbindin, and anticalretinin. External and central anterior olfactory nuclei also show characteristic cytoarchitectural and chemoarchitectural features. The medial olfactory peduncle seems to differ considerably from that in rodents. A small taenial structure can be separated from the hippocampal continuation. This taenia tecti presumably corresponds to the superior part of the tenia tecti in rodents, but no homologue of the rodent's prominent inferior taenia tecti could be found. The connections of bulbar and retrobulbar regions are similar to those seen in other mammals. Interbulbar projection systems connect the two olfactory bulbs through an external (topographic) and central (nontopographic) anterior nucleus; however, the topographic arrangement of the intrabulbar association system seems to differ from that seen in rodents. A reciprocity of direct olfactory bulb connections with the frontal (sulcal/orbital) cortex was found in the tenrec that has not been reported so far in other species.

Coexistence of erythrocyte agglutination and EDTA-dependent platelet clumping in a patient with thymoma and plasmocytoma.

For 8 years, EDTA-dependent pseudothrombocytopenia was observed in a 55-year-old woman with a history of rheumatoid arthritis who had undergone surgery for lymphoepithelial thymoma 11 years earlier. The clinical picture was characterized by the presence of platelet clumps and antiplatelet antibodies of the IgM class. With the recent appearance of a solitary extramedullary plasmocytoma in the right retrobulbar region and the detection of an IgGlambda monoclonal gammopathy, blood examination also revealed erythrocyte agglutinates alongside the platelet clumps and the presence of a cold IgG antibody with antiI specificity. Both phenomena were observed in vitro when the sample temperature declined to 20 degrees C to 25 degrees C, but not at 37 degrees C. While the EDTA-dependent antiplatelet antibodies did not appear to be chronologically correlated with the patient's diseases, the cold antierythrocyte autoantibodies were strictly related to the plasmocytoma and the IgGlambda monoclonal component in serum. To our knowledge, this is the first description of an association between EDTA-dependent platelet and erythrocyte agglutinates, with a clinical picture of pseudothrombocytopenia and pseudoerythrocytopenia due to cold agglutinins.

A CASE OF LOCALIZED PANCREATITIS WITH DUODENAL STRICTURE

We experienced a case of localized pancreatitis which presented difficulty in diagnosis because we had to treat primarily a stricture of the descending portion of the duodenum which provoked strong clinical findings. A 57-year-old man was seen at the hospital because of epigastric pain. Endoscopic examination revealed a shallow ulcerative lesion with crater at the retrobulbar region. No malignant evidence was found on a biopsy and conservative therapy was started. But no remission was attained and the patient was admitted to the hospital. Hypotention duodenoscopy visualized a severe stricture in the descending portion of duodenum. Abdominal ultrasonography and CT revealed a tumorous lesion about 4cm in diameter at the head of pancreas and thickening of hte duodenal wall. No abnormality was noted on endoscopic retrograde cholangiopancreascopy (ERCP). Since we could not completely rule out a possibility of malignant disease and the stricture findings and abdominal signs were clinically strong, the patient was operated on. During operation a hard mass was palpated in the upper portion of the pancreatic head. Intraoperative frozen section diagnosis indicated no malignancy, but a pacreatoduodenectomy was performed. Pathological study revealed that the tumor was localized chronic pancreatitis with inflammatory infiltration into the duodenal wall.