Aim: To review the clinical features, management, and outcomes of surgical treatment of eyelid squamous cell carcinoma (SCC). Methods: A retrospective review of all eyelid SCCs treated between 1992 and 2001. Results: 51 cases were identified in 50 patients. Patient ages ranged from 26 to 93 years, with a mean age of 65 years. 33 patients were male and 17 were female. The lesion was found on the lower lid in 31 cases, upper lid in five cases, lateral canthus in six cases, and medial canthus in nine cases. Perineural invasion was found in four patients, and orbital invasion in three patients. Recurrence occurred in one patient. Treatment was by complete excision with histological confirmation of clear margins. Exenteration was required in three patients. No patients developed lymph node or distant metastases. One patient, who declined treatment, died as a result of the tumour. Mean follow up was 31.1 months. Conclusions: Eyelid SCC is a relatively uncommon, but potentially fatal disease. However, if detected early and treated adequately, the prognosis is generally excellent. Treatment by complete excision with histological confirmation of tumour clearance is recommended. Perineural spread is an adverse prognostic sign, which may require postoperative radiotherapy. Orbital invasion is a rare complication but, if recognised early, can be treated effectively with exenteration. Because presentation varies and histological examination is required for accurate diagnosis, any suspicious lesion occurring on the eyelids should be excised or biopsied. All patients with eyelid SCC should be advised of the risk of recurrent or new tumours and encouraged to attend lifelong follow up. Prevention remains of prime importance in minimising the morbidity and mortality of these lesions. S quamous cell carcinoma (SCC) is an invasive epithelial malignancy showing keratinocytic differentiation. It is the second most common malignant neoplasm of the eyelids, 1 comprising 5-10% of all eyelid malignancies. The incidence for eyelid SCC has been reported to be between 0.09 and 2.42 cases per 100 000 population.2 Extrinsic risk factors include ultraviolet light/actinic damage and exposure to arsenic, hydrocarbons, radiation, or immunosuppressive drugs. 3Intrinsic risk factors include albinism, pre-existing chronic skin lesions and genetic skin disorders such as xeroderma pigmentosum and epidermodysplasia verruciformis.Because of the significant morbidity of these lesions and in order to better define the clinical features and treatment outcomes, and to make management recommendations, we conducted a review of all eyelid SCCs treated over a 9 year period. METHODSA retrospective medical record review was conducted of all eyelid squamous cell carcinomas seen in the practice of one of the authors (TJS) in the 9 years from 1992 to 2001. Cases were identified by searching the practice records of the author and hospital and pathology laboratory computerised databases. Included were all lesions originating on the eyelids or canthi with a pathologica...

Recent studies have applied dimensionality reduction methods to understand how the multi-dimensional structure of neural population activity gives rise to brain function. It is unclear, however, how the results obtained from dimensionality reduction generalize to recordings with larger numbers of neurons and trials or how these results relate to the underlying network structure. We address these questions by applying factor analysis to recordings in the visual cortex of non-human primates and to spiking network models that self-generate irregular activity through a balance of excitation and inhibition. We compared the scaling trends of two key outputs of dimensionality reduction—shared dimensionality and percent shared variance—with neuron and trial count. We found that the scaling properties of networks with non-clustered and clustered connectivity differed, and that the in vivo recordings were more consistent with the clustered network. Furthermore, recordings from tens of neurons were sufficient to identify the dominant modes of shared variability that generalize to larger portions of the network. These findings can help guide the interpretation of dimensionality reduction outputs in regimes of limited neuron and trial sampling and help relate these outputs to the underlying network structure.

Cystic fibrosis liver disease (CFLD), which results from progressive hepatobiliary fibrosis, is an important cause of morbidity and mortality, but it is difficult to identify before portal hypertension (PHT) ensues. Clinical signs, serum alanine aminotransferase (ALT) levels, and ultrasound (US) are widely applied, but their value in predicting the presence of cirrhosis, the development of PHT, or adverse outcomes is undetermined. The potential gold standard, liver biopsy, is not standard practice and, notwithstanding sampling error considerations, has not been systematically evaluated. Forty patients with cystic fibrosis (median age 5 10.6 years) with abnormal clinical, biochemical, and US findings were subjected to dual-pass percutaneous liver biopsy. Clinical outcomes were recorded over 12 years of follow-up (median 5 9.5 years for survivors). Logistic regression and receiver operating characteristic analyses were applied to predict hepatic fibrosis (which was assessed by fibrosis staging and quantitative immunohistochemistry) and the occurrence of PHT. PHT occurred in 17 of 40 patients (42%), including 6 of 7 (17%) who died during follow-up. Clinical examination, serum ALT levels, and US findings failed to predict either the presence of liver fibrosis or the development of PHT. Fibrosis staging on liver biopsy, where the accuracy was improved by dual passes (P 5 0.002, nonconcordance 5 38%), predicted the development of PHT (P < 0.001), which occurred more frequently and at a younger age in those with severe fibrosis. Conclusion: Clinical modalities currently employed to evaluate suspected CFLD help to identify a cohort of children at risk for liver disease and adverse outcomes but do not predict an individual's risk of liver fibrosis or PHT development. Liver fibrosis on biopsy predicts the development of clinically significant liver disease. Dual passes help to address sampling concerns. Liver biopsy has a relevant role in the management of patients with suspected CFLD and deserves more widespread application.