Orbital metastasis of myxofibrosarcoma.

Myxofibrosarcoma (MFS), a common sarcoma in adults, typically affects the extremities. Primary orbital involvement is uncommon, and orbital metastasis is exceedingly rare. We describe a case of orbital MFS due to metastasis and provide an updated literature review. A 56-year-old woman presented with 2 months of progressive right eye proptosis. Relevant history included left palmar MFS excised 2 years prior. Examination demonstrated proptosis and restriction in abduction of her right eye without optic nerve compromise. Imaging revealed a well-circumscribed right orbital mass. Initial biopsy showed glandular tissue with chronic inflammation without an evidence of malignancy. She subsequently developed worsening proptosis, complete ophthalmoplegia, and a new afferent pupillary defect. Repeat orbital excisional biopsy with deeper dissection demonstrated high-grade MFS consistent with metastasis. She underwent chemoradiation with resolution of her lesion. Literature review identified 12 previously reported cases of MFS, only two of which involved metastasis to the orbit and were associated with worse prognosis. This report highlights a rare case of orbital metastasis of MFS with high-grade features confirmed on histopathology and provides an updated literature review. Prompt diagnosis and complete removal of MFS located both systemically and in the orbit are essential due to the metastatic potential.

Apoptotic Marker Expression of Resected Lacrimal Gland Adenoid Cystic Carcinoma Tumor Margins After Intra-arterial Chemotherapy and Globe-Sparing Excision.

PURPOSE: Lacrimal gland adenoid cystic carcinoma (LGACC) is a rare orbital malignancy with devastating lethality. Neoadjuvant intra-arterial chemotherapy (IACC) has demonstrated cytoreductive effects on LGACC macroscopically, but limited studies have examined cellular and molecular determinants of the cytoreductive effect. This post hoc study assessed apoptotic marker expression on excised tumor specimens after neoadjuvant IACC and globe-sparing resection, emphasizing the examination of tumor margins. METHODS: This retrospective study identified LGACC specimens resected in a globe-sparing technique after neoadjuvant IACC by reviewing the Florida Lions Ocular Pathology database at Bascom Palmer Eye Institute. Histopathology slides of the specimens were re-examined to confirm the diagnosis and identify the tumor margin. Immunofluorescent staining was performed for apoptotic markers, including P53, cleaved caspase-3, cleaved PARP-1, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Positive expression was determined by comparison to the negative control. RESULTS: Tumor specimens from 5 patients met inclusion criteria. All 5 cases were positive at the center and the margin for TUNEL, p53, and cleaved caspase-3. One case did not show positive expression of cleaved PARP-1 at the margin but was positive for the other apoptotic markers. CONCLUSIONS: This post hoc study demonstrated positive staining for multiple apoptotic markers in post-IACC tumor specimens at the tumor center and margin. Apoptotic marker expression along the margins of post-treatment specimens is important, as it may offer surrogate information to speculate on the state of residual cancer cells adjacent to the excision margin inadvertently remaining in the orbit.

Vectorized instructive signals in cortical dendrites during a brain-computer interface task.

Backpropagation of error is the most widely used learning algorithm in artificial neural networks, forming the backbone of modern machine learning and artificial intelligence1,2. Backpropagation provides a solution to the credit assignment problem by vectorizing an error signal tailored to individual neurons. Recent theoretical models have suggested that neural circuits could implement backpropagation-like learning by semi-independently processing feedforward and feedback information streams in separate dendritic compartments3-7. This presents a compelling, but untested, hypothesis for how cortical circuits could solve credit assignment in the brain. We designed a neurofeedback brain-computer interface (BCI) task with an experimenter-defined reward function to evaluate the key requirements for dendrites to implement backpropagation-like learning. We trained mice to modulate the activity of two spatially intermingled populations (4 or 5 neurons each) of layer 5 pyramidal neurons in the retrosplenial cortex to rotate a visual grating towards a target orientation while we recorded GCaMP activity from somas and corresponding distal apical dendrites. We observed that the relative magnitudes of somatic versus dendritic signals could be predicted using the activity of the surrounding network and contained information about task-related variables that could serve as instructive signals, including reward and error. The signs of these putative teaching signals both depended on the causal role of individual neurons in the task and predicted changes in overall activity over the course of learning. These results provide the first biological evidence of a backpropagation-like solution to the credit assignment problem in the brain.

Osteolytic sarcoidosis of the orbit without pulmonary involvement.

A 69-year-old woman with a history of a left orbital mass presented to the emergency room with progressive breakthrough pain in her left orbit despite medical therapy. On examination, there was extraocular motility restriction with diplopia upon left supraduction. Computed tomography (CT) scan of the orbits revealed soft tissue thickening of the left medial and superior periorbita and left lacrimal fossa; bony erosion of the left frontal bone, left orbital roof, and left lamina papyracea; and bilateral mass-like enlargement of the extraocular muscles. An orbitotomy with incisional biopsy was performed, and histopathological examination revealed non-caseating granulomatous inflammation consistent with sarcoidosis. Chest imaging demonstrated no sequela of pulmonary sarcoidosis, and her serum angiotensin converting enzyme (ACE) level was within normal range. She was treated with high-dose oral steroids with resolution of her symptoms. Her pain returned at the conclusion of the steroid taper, and it was controlled with chronic subcutaneous methotrexate and adalimumab injections.

Dendritic Mechanisms for In Vivo Neural Computations and Behavior.

Dendrites receive the vast majority of a single neuron's inputs, and coordinate the transformation of these signals into neuronal output. Ex vivo and theoretical evidence has shown that dendrites possess powerful processing capabilities, yet little is known about how these mechanisms are engaged in the intact brain or how they influence circuit dynamics. New experimental and computational technologies have led to a surge in interest to unravel and harness their computational potential. This review highlights recent and emerging work that combines established and cutting-edge technologies to identify the role of dendrites in brain function. We discuss active dendritic mediation of sensory perception and learning in neocortical and hippocampal pyramidal neurons. Complementing these physiological findings, we present theoretical work that provides new insights into the underlying computations of single neurons and networks by using biologically plausible implementations of dendritic processes. Finally, we present a novel brain-computer interface task, which assays somatodendritic coupling to study the mechanisms of biological credit assignment. Together, these findings present exciting progress in understanding how dendrites are critical for in vivo learning and behavior, and highlight how subcellular processes can contribute to our understanding of both biological and artificial neural computation.

Squamoid Eccrine Ductal Carcinoma of the Eyelid: Clinicopathologic Correlation of a Case.

Squamoid eccrine ductal carcinoma (SEDC) is a rare cutaneous neoplasm that often manifests as a plaque or nodule in sun-exposed areas of older patients. Herein, the authors report the first case of SEDC in the eyelid. A 76-year-old man presented with a 2.5 × 1.5 mm area of left upper eyelid erythema, thickening, ulceration, and scaling with madarosis superotemporally just above the lash line. Full-thickness wedge biopsy demonstrated irregular epithelial tubules with nuclear atypia and focal squamous differentiation, consistent with SEDC. The patient underwent Mohs resection and has had no recurrence approximately 27 months after surgical removal. The authors present this case to raise awareness of SEDC to ophthalmologists as all previous cases have been described in the nonophthalmic literature. A full-thickness biopsy is recommended to avoid misdiagnosing SEDC as squamous cell carcinoma (SCC), a less aggressive tumor. With greater awareness, there may be increased recognition of this likely underreported, more malignant entity.

Ocular Anterior Segment Pathology in the Emergency Department: A 5-Year Study.

INTRODUCTION: Patients with ocular complaints frequently present to emergency departments (EDs) for care. Emergency department practitioners are often the first to evaluate these patients and determine the next steps in their care, which can be a challenging task. The purpose of this study is to determine the frequency of anterior segment pathology in the setting of the ED in hopes that this information will be useful in creating more effective management algorithms. METHODS: A retrospective study based on electronic patient charts from the University of California Davis ED that included ophthalmology consults. We reviewed the charts for demographic data, as well as visual acuity (VA), intraocular pressure (IOP), and diagnosis as determined by ED and ophthalmology personnel, respectively. RESULTS: The most common anterior segment diagnoses were uveitis, corneal abrasion, corneal ulcer, meibomian gland dysfunction/dry eyes/blepharitis/punctate epithelial erosions, and conjunctivitis/epidemic keratoconjunctivitis. Emergency Department personnel measured the VA and IOP in 40.8% and 16.7% of patients, respectively. The ophthalmologist measured the VA and IOP in 78.4% and 95.1% of patients, respectively. The percentage agreement in VA measurement between ophthalmology and ED was 11.8%. The percentage agreement in IOP measurement between ophthalmology and ED was 0.86%. The percentage agreement in diagnosis between ophthalmology and ED was 49.4%. CONCLUSIONS: Most ocular conditions that present in the ED are nonurgent and can be treated in an outpatient setting. However, ED personnel are often unable to obtain the proper "ocular vital signs" (the VA and IOP) and diagnoses. Our findings suggest a need for clear interprofessional discussion in creating an algorithm for triage and the management of eye conditions in the ED to deliver effective care.

Response learning stimulates dendritic spine growth on dorsal striatal medium spiny neurons.

Increases in the number and/or the size of dendritic spines, sites of excitatory synapses, have been linked to different types of learning as well as synaptic plasticity in several brain regions, including the hippocampus, sensory cortex, motor cortex, and cerebellum. By contrast, a previous study reported that training on a maze task requiring the dorsal striatum has no effect on medium spiny neuron dendritic spines in this area. These findings might suggest brain region-specific differences in levels of plasticity as well as different cellular processes underlying different types of learning. No previous studies have investigated whether dendritic spine density changes may be localized to specific subpopulations of medium spiny neurons, nor have they examined dendritic spines in rats trained on a dorsolateral striatum-dependent maze task in comparison to rats exposed to the same type of maze in the absence of training. To address these questions further, we labeled medium spiny neurons with the lipophilic dye DiI and stained for the protein product of immediate early gene zif 268, an indirect marker of neuronal activation, in both trained and untrained groups. We found a small but significant increase in dendritic spine density on medium spiny neurons of the dorsolateral striatum after short-term intensive training, along with robust increases in the density of spines with mushroom morphology coincident with reductions in the density of spines with thin morphology. However, these results were not associated with zif 268 expression. Our findings suggest that short-term intensive training on a dorsolateral striatum-dependent maze task induces rapid increases in dendritic spine density and maturation on medium spiny neurons of the dorsolateral striatum, an effect which may contribute to early acquisition of the learned response in maze training.