Pseudocystic appearance of an orbital carcinoid metastasis.

Carcinoid tumours are a low-grade neuroendocrine malignancy that infrequently metastisizes to orbital structures. The typical radiological appearance of carcinoid is a solid, well-circumscribed mass that enhances with contrast. We present a case of orbital carcinoid metastasis with pseudocystic radiological appearance and review of the literature.

T-Cell Large Granular Lymphocyte Leukemia in the Lower Eyelid.

The authors describe a case of T-cell large granular lymphocytic leukemia nodular lesion of the eyelid. To their knowledge, this has not been reported previously to occur in the eyelids. They have also reviewed previous literature reports on similar skin lesions in areas elsewhere.

Malignant hair follicle tumors of the periorbital region: A review of literature and suggestion of a management guideline.

Malignant hair follicle tumors are rare skin adnexal malignancies that have a predilection for the head and neck region. They can be categorized into a number of different subtypes. Histologically, they are distinct from their benign counterpart. To the best of our knowledge, there is no extensive review of these malignancies, especially in the periorbital region. We aim to provide a literature review and a guideline for management of these malignant tumors in the periorbital region. Database from Medline, PubMed, Embase, and Google Scholar were consulted. A total of 16 cases from the literature on hair follicle malignancies in the periorbital region were included in this review. The clinical presentations, diagnostic patterns, investigations used, and best management approach of these tumors are discussed. The American Joint Committee on Cancer (AJCC) 7(th) edition carcinoma of the eyelid staging system was used to describe their behaviors. We recommend wide excision surgery and a close follow-up for these tumors. Tumors presenting with a late stage require work-up for distant metastasis and consideration for exenteration procedures. The role of radiotherapy and chemotherapy in this context is still uncertain.

Quantum biology of the retina.

The emerging field of quantum biology has led to a greater understanding of biological processes at the microscopic level. There is recent evidence to suggest that non-trivial quantum features such as entanglement, tunnelling and coherence have evolved in living systems. These quantum features are particularly evident in supersensitive light-harvesting systems such as in photosynthesis and photoreceptors. A biomimetic strategy utilizing biological quantum phenomena might allow new advances in the field of quantum engineering, particularly in quantum information systems. In addition, a better understanding of quantum biological features may lead to novel medical diagnostic and therapeutic developments. In the present review, we discuss the role of quantum physics in biological systems with an emphasis on the retina.

Orbital compartment syndrome following transvenous embolization of carotid-cavernous fistula.

Superior ophthalmic vein (SOV) thrombosis is a rare complication of carotid-cavernous fistula (CCF) embolization and is usually associated with a paradoxical worsening of signs followed by subsequent spontaneous resolution. We report a case in a 69-year-old female who developed orbital compartment syndrome due to SOV thrombosis following transvenous embolization of an indirect CCF. The patient was treated with an urgent lateral canthotomy and cantholysis and had good recovery. This report demonstrates that the paradoxical worsening due to SOV thrombosis in CCF may result in orbital compartment syndrome and require early recognition and prompt decompressive measures to avoid permanent visual sequelae.

Elusively reaching the apex.

A 64-year-old man presented with a 3-month history of diplopia and left-sided proptosis. Examination was significant for impairment of his left second, third, fourth, fifth, sixth, and seventh cranial nerves. Magnetic resonance imaging revealed a left orbital apex and cavernous sinus lesion. However, subtle thickening of his left frontal and supraorbital nerve was not identified until later. A trial of steroids provided minimal effect. Biopsy of the lesion showed a well-differentiated squamous cell carcinoma. The patient was subsequently managed with palliative radiotherapy.

Creatine is Neuroprotective to Retinal Neurons In Vitro But Not In Vivo.

Purpose: To investigate the neuroprotective properties of creatine in the retina using in vitro and in vivo models of injury. Methods: Two different rat retinal culture systems (one containing retinal ganglion cells [RGC] and one not) were subjected to either metabolic stress, via treatments with the mitochondrial complex IV inhibitor sodium azide, or excitotoxic stress, via treatment with N-methyl-D-aspartate for 24 hours, in the presence or absence of creatine (0.5, 1.0, and 5.0 mM). Neuronal survival was assessed by immunolabeling for cell-specific antigens. Putative mechanisms of creatine action were investigated in vitro. Expression of creatine kinase (CK) isoenzymes in the rat retina was examined using Western blotting and immunohistochemistry. The effect of oral creatine supplementation (2%, wt/wt) on retinal and blood creatine levels was determined as well as RGC survival in rats treated with N-methyl-D-aspartate (NMDA; 10 nmol) or high IOP-induced ischemia reperfusion. Results: Creatine significantly prevented neuronal death induced by sodium azide and NMDA in both culture systems. Creatine administration did not alter cellular adenosine triphosphate (ATP). Inhibition of CK blocked the protective effect of creatine. Retinal neurons, including RGCs, expressed predominantly mitochondrial CK isoforms, while glial cells expressed exclusively cytoplasmic CKs. In vivo, NMDA and ischemia reperfusion caused substantial loss of RGCs. Creatine supplementation led to elevated blood and retinal levels of this compound but did not significantly augment RGC survival in either model. Conclusions: Creatine increased neuronal survival in retinal cultures; however, no significant protection of RGCs was evident in vivo, despite elevated levels of this compound being present in the retina after oral supplementation.