Bilateral auricular squamous cell carcinomas with perineural invasion

BACKGROUND

Bilateral squamous cell carcinoma (SCC) of the external ears is a rare phenomenon, and we are unaware of instances of bilateral perineural involvement.

OBJECTIVE

To describe bilateral auricular SCCs, each with perineural invasion.

METHODS

Case report and literature review.

RESULTS

Histopathologic examination revealed perineural invasion in both tumors.

CONCLUSION

This appears to be an unusual presentation of bilateral auricular SCCs with perineural invasion in an elderly immunocompromised patient.

Basal cell carcinoma arising in a cleft lip repair scar

BACKGROUND

A case of basal cell carcinoma (BCC) developing in the repair scar of a cleft lip is presented.

OBJECTIVE

Primary BCCs arising in surgical scars are very rare and no known reported cases exist of a BCC developing in a surgically repaired cleft lip scar.

METHODS

A 69-year-old white man presented with a 5 mm primary BCC on his upper lip at the site of his cleft lip repair scar. The diagnosis was made by a tangential biopsy that showed an ulcerated BCC.

RESULTS

Review of the medical literature indicates that a scar may be an independent risk factor for developing BCC.

CONCLUSION

BCC may rarely arise in a cleft lip repair scar.

Study design in the evaluation of breast cancer imaging technologies

RATIONALE AND OBJECTIVES

Bringing a new imaging technology to market is a complex process. Beyond conceptualization and proof of concept, obtaining U.S. Food and Drug Administration (FDA) approval for clinical use depends on the documented experimental establishment of safety and efficacy. In turn, safety and efficacy are evaluated in the context of the intended use of the technology. The purpose of this study was to examine a conceptual framework for technology development and evaluation, focusing on new breast imaging technologies as a highly visible and current case in point.

MATERIALS AND METHODS

The FDA views technology development in terms of a preclinical and four clinical phases of assessment. With a concept of research and development as a learning model, this phased-assessment concept of regulatory review against intended use was integrated with a five-level version of a hierarchy-of-efficacy framework for evaluating imaging technologies. Study design and analysis issues are presented in this context, as are approaches to supporting expanded clinical indications and new intended uses after a new technology is marketed.

CONCLUSION

Breast imaging technologies may be intended for use as replacements for standard-of-care technologies, as adjuncts, or as complementary technologies. Study designs must be appropriate to establish claims of superiority or equivalence to the standard for the intended use. Screening technologies are ultimately judged on their demonstrated effectiveness in decreasing cause-specific mortality through early detection, but they may be brought to market for other uses on the basis of lesser standards of efficacy (eg, sensitivity, specificity, positive and negative predictive value, and stage of disease detected).

Dermatologist and electrologist perspectives on laser procedures by nonphysicians

BACKGROUND

As hair removal technology continues to evolve and new equipment comes to market, conflicts may develop between dermatologists and electrologists regarding the professional control and use of these devices.

METHODS

A total of 1004 Fellows of the American Academy of Dermatology and 719 electrologists from the southern United States were anonymously surveyed about clinical laser procedures (CLPs).

RESULTS

Compared to electrologists, dermatologists were more likely to support clinical laser regulations that placed licensed physicians in control (P =.001) and preferred that a delegating physician be physically present on the premises when CLPs were performed (P =.001). If a laser device was invented for permanent hair removal that was identical to traditional needle/probe electrolysis in every respect except energy type ("laser fiberoptic probe," LFP), electrologists were more likely than dermatologists to support independent use of this device by electrologists (P =.001). A greater percentage of electrologists from Texas, a state without electrolysis licensing, were more likely to support the unlicensed use of the LFP and CLPs than electrologists from states requiring electrolysis licensing.

CONCLUSIONS

These data are consistent with previously published literature and permit a greater understanding of the multiple attitudinal, regulatory, and ethical issues involved when considering delegated and independent CLPs by electrologists.

Feature selection and classifier performance in computer-aided diagnosis: the effect of finite sample size

In computer-aided diagnosis (CAD), a frequently used approach for distinguishing normal and abnormal cases is first to extract potentially useful features for the classification task. Effective features are then selected from this entire pool of available features. Finally, a classifier is designed using the selected features. In this study, we investigated the effect of finite sample size on classification accuracy when classifier design involves stepwise feature selection in linear discriminant analysis, which is the most commonly used feature selection algorithm for linear classifiers. The feature selection and the classifier coefficient estimation steps were considered to be cascading stages in the classifier design process. We compared the performance of the classifier when feature selection was performed on the design samples alone and on the entire set of available samples, which consisted of design and test samples. The area Az under the receiver operating characteristic curve was used as our performance measure. After linear classifier coefficient estimation using the design samples, we studied the hold-out and resubstitution performance estimates. The two classes were assumed to have multidimensional Gaussian distributions, with a large number of features available for feature selection. We investigated the dependence of feature selection performance on the covariance matrices and means for the two classes, and examined the effects of sample size, number of available features, and parameters of stepwise feature selection on classifier bias. Our results indicated that the resubstitution estimate was always optimistically biased, except in cases where the parameters of stepwise feature selection were chosen such that too few features were selected by the stepwise procedure. When feature selection was performed using only the design samples, the hold-out estimate was always pessimistically biased. When feature selection was performed using the entire finite sample space, the hold-out estimates could be pessimistically or optimistically biased, depending on the number of features available for selection, the number of available samples, and their statistical distribution. For our simulation conditions, these estimates were always pessimistically (conservatively) biased if the ratio of the total number of available samples per class to the number of available features was greater than five.

Clinical management of the acute sunburn reaction

Critical reviews of published human studies about pharmacologic agents used to treat the sunburn reaction show that systemic and topical corticosteroids have little or no clinically important effect on the sunburn reaction. Systemic and topical nonsteroidal anti-inflammatory drugs, when used at dosages to achieve optimal serum levels for anti-inflammatory effect, only result in an early and mild reduction of ultraviolet B-induced erythema. Due to the lack of demonstrated clinical efficacy of these and other medicines to eliminate sunburn or decrease healing time, we currently suggest conservative local symptomatic treatment with adequate pain control until the sunburn naturally resolves.

Components-of-variance models and multiple-bootstrap experiments: an alternative method for random-effects, receiver operating characteristic analysis

RATIONALE AND OBJECTIVES

The purpose of this study was to develop an alternative approach to random-effects, receiver operating characteristic analysis inspired by a general formulation of components-of-variance models. The alternative approach is a higher-order generalization of the Dorfman, Berbaum, and Metz (DBM) approach that yields additional information on the variance structure of the problem.

MATERIALS AND METHODS

Six population experiments were designed to determine the six variance components in the DBM model. For practical problems, in which only a finite set of readers and patients are available, six analogous bootstrap experiments may be substituted for the population experiments to estimate the variance components. Monte Carlo simulations were performed on the population experiments, and those results were compared with the corresponding multiple-bootstrap estimates and those obtained with the DBM approach. Confidence intervals on the difference of ROC parameters for competing diagnostic modalities were estimated, and corresponding comparisons were made.

RESULTS

For mean values, the agreement of present estimates of variance structures with population results was excellent and, when suitably weighted and mixed, similar to or closer than that with the DBM method. For many variance structures, the confidence intervals in this study for the difference in ROC area between modalities were comparable to those with the DBM method. When reader variability was large, however, mean confidence intervals from this study were tighter than those with the DBM method and closer to population results.

CONCLUSION

The jackknife approach of DBM provides a linear approximation to receiver-operating-characteristic statistics that are intrinsically nonlinear. The multiple-bootstrap technique of this study, however, provides a more general, nonparametric, maximum-likelihood approach. It also yields estimates of the variance structure previously unavailable.

Differential expression of the HHV-8 vGCR cellular homolog gene in AIDS-associated and classic Kaposi's sarcoma: potential role of HIV-1 Tat

Human herpesvirus 8 (HHV-8) has been causally linked to Kaposi's sarcoma (KS). There is significant homology between some HHV-8 genes and cellular genes including D-type cyclin (vCYC), G protein coupled receptor (vGCR), macrophage inflammatory proteins (vMIP-I, vMIP-II), bcl-2 (vBCL2), interferon regulatory factor-1 (vIRF1), interleukin-6 (vIL6), and complement-binding protein (vCBP). In this study, we analyzed expression of these viral homologs and HIV-1 Tat by reverse-transcriptase polymerase chain reaction (RT-PCR) coupled with Southern blot hybridization in AIDS-KS (AKS) tissue, classic KS tissue(CKS), and peripheral blood mononuclear cells, and phorbol ester (TPA)-treated and untreated HHV-8 positive lymphoma cells (BCBL1). While vCYC (AKS 6 of 6; CKS 3 of 3), vMIP-I (AKS 5 of 6, CKS 3 of 3), vBCL2 (AKS 6 of 6; CKS 3 of 3), and vIRF1 (AKS 5 of 6, CKS 3 of 3) transcripts were detected in both AKS and CKS, vGCR and HIV-1 Tat were expressed only in AKS samples (vGCR: AKS 3 of 6, CKS 0 of 3; Tat: AKS 4 of 6, CKS 0 of 3). vMIPII, vCBP, and vIL6 expression were not detected in any KS samples. Since vGCR expression is limited to AKS, it is possible that vGCR is activated by HIV-1 Tat. These results suggest that HIV-1 Tat may contribute to AKS pathogenesis through the tumorigenic and angiogenic effects of vGCR.

Classifier design for computer-aided diagnosis: effects of finite sample size on the mean performance of classical and neural network classifiers

Classifier design is one of the key steps in the development of computer-aided diagnosis (CAD) algorithms. A classifier is designed with case samples drawn from the patient population. Generally, the sample size available for classifier design is limited, which introduces variance and bias into the performance of the trained classifier, relative to that obtained with an infinite sample size. For CAD applications, a commonly used performance index for a classifier is the area, Az, under the receiver operating characteristic (ROC) curve. We have conducted a computer simulation study to investigate the dependence of the mean performance, in terms of Az, on design sample size for a linear discriminant and two nonlinear classifiers, the quadratic discriminant and the backpropagation neural network (ANN). The performances of the classifiers were compared for four types of class distributions that have specific properties: multivariate normal distributions with equal covariance matrices and unequal means, unequal covariance matrices and unequal means, and unequal covariance matrices and equal means, and a feature space where the two classes were uniformly distributed in disjoint checkerboard regions. We evaluated the performances of the classifiers in feature spaces of dimensionality ranging from 3 to 15, and design sample sizes from 20 to 800 per class. The dependence of the resubstitution and hold-out performance on design (training) sample size (Nt) was investigated. For multivariate normal class distributions with equal covariance matrices, the linear discriminant is the optimal classifier. It was found that its Az-versus-1/Nt curves can be closely approximated by linear dependences over the range of sample sizes studied. In the feature spaces with unequal covariance matrices where the quadratic discriminant is optimal, the linear discriminant is inferior to the quadratic discriminant or the ANN when the design sample size is large. However, when the design sample is small, a relatively simple classifier, such as the linear discriminant or an ANN with very few hidden nodes, may be preferred because performance bias increases with the complexity of the classifier. In the regime where the classifier performance is dominated by the 1/Nt term, the performance in the limit of infinite sample size can be estimated as the intercept (1/Nt= 0) of a linear regression of Az versus 1/Nt. The understanding of the performance of the classifiers under the constraint of a finite design sample size is expected to facilitate the selection of a proper classifier for a given classification task and the design of an efficient resampling scheme.

Uncertainties in estimates of lesion detectability in diagnostic ultrasound

Statistical properties of estimates of focal lesion detectability for medical ultrasonic imaging systems are investigated. Analytic forms for bias and variance of estimates of detectability of a lesion consisting of fully developed speckle embedded within a speckle background are derived. Bias and variance of estimates of detectability are investigated using a computer simulation and experiments on tissue-mimicking phantoms. This work offers a systematic methodology for interpreting measurements on phantoms in order to assess lesion detectability. In addition, it provides useful results which may be used to improve design of phantoms and experiments for imaging-system performance assessment.

Beach holiday sunburn: the sunscreen paradox and gender differences

A survey about sunbathing practices was performed on a summer holiday weekend at a Galveston beach. The likelihood of sunburn increased with increasing duration of sun exposure, with 100% of subjects experiencing sunburn after exposure > or = 4.5 hours. Men exhibited a significantly higher frequency of sunburn, employed fewer sun-protective measures, and demonstrated less knowledge concerning sun safety information and skin cancer than women. This information suggests a need for greater educational efforts directed toward changing public attitudes about preventing sunburn, especially those of men, that currently lead to high-risk sunbathing behavior.

[Effect of subjective theories on the coping with illness process--exemplified by patients with chronic pancreatitis]

The concept of locus of control, as a basic aspect of subjective self-perception and world perception, has turned out to be an important construct in the area of psychosomatic medicine for the explanation and prediction of illness-relevant behaviour. This study investigates the influence of illness-specific locus of control on the course of the disease in patients suffering from chronic pancreatitis. While most investigations in this area of research are methodologically restricted to paper-and-pencil questionnaires, the present study registered the concept of locus of control within the metatheoretical framework of "research programme subjective theories". This programme focuses on the capacity of patients to create their own models of their relationship with the world. The procedure involves two stages of research: In the first phase of communicative validation the patient is interviewed about the possibility to influence the course of his disease. A few days later, in a second session, the patient models together with the interviewer a structure of his subjective theory. In the second stage, the phase of explanatory validation, this model will be tested using empirical methods for validation. Compared to a paper-and-pencil questionnaire this procedure means more expenditure for research. On the other hand the results are detailed and specified. Hence, it can be shown that patients dispose over a set of subjective theories on how to influence the course of their illness. These subjective theories determine the patients' coping styles. Methodological and theoretical consequences for coping research and treatment of chronic diseases are discussed.

Tumor remnants within giant cells following irradiation of cutaneous squamous cell carcinoma

BACKGROUND

The histopathologic effects of curative doses of radiation therapy on cutaneous squamous cell carcinoma (SCC) have not been well described in the dermatologic literature.

OBJECTIVE

To understand the histopathologic process of cutaneous SCC involution following radiation treatment.

METHODS

Hematoxylin-eosin stain and immunoperoxidase stains for keratin were performed on tissue from the site of a primary cutaneous SCC 2 months after completion of fractionated radiation therapy (7000 cGy total) but prior to clinical involution.

RESULTS

Histopathological examination of the irradiated SCC revealed dermal keratin pearls and keratinocytic necrosis resembling apoptosis as well as inflammation and foreign body giant cell reaction. Immunoperoxidase staining for keratin revealed cellular remnants of cutaneous SCC without intact keratinocytic nuclei within giant cells.

CONCLUSION

Complete clinical resolution of the SCC over the next several weeks without recurrence after 15 months confirmed the histopathologic findings of tumor destruction by primary radiation therapy.

Metastatic basal cell carcinoma presenting as unilateral lymphedema

BACKGROUND

Metastatic basal cell carcinoma (MBCC) is rare, occurring in only 0.0028-0.55% of all basal cell carcinomas (BCCs). Patients with MBCC may present with a variety of findings, related to the site of metastasis.

OBJECTIVE

Clinical presentation of a MBCC that became symptomatic due to unilateral lymphedema and a review of the relevant literature.

METHODS

Case report with literature review.

RESULTS

Patients may present with lymphadenopathy, ulcerations, anemia, bone pain, or muscle weakness related to the site of metastasis. In this reported case, MBCC presented as unilateral lymphedema. Risk factors for MBCC include radiation, large and invasive tumors, and a history of recurrence. The average survival time for localized lymph node metastasis in BCC is 3.6 years. This patient is currently 2 years since MBCC presentation and is currently without evidence of recurrence.

CONCLUSION

To our knowledge, we report the first case of MBCC that presented as unilateral lymphedema.

Mohs micrographic surgery

Mohs micrographic surgery (MMS) is a specialized type of minimal marginal surgery that offers cure rates superior to other options in the treatment of contiguous skin cancers in selected settings. Developed by Dr. Frederic E. Mohs, the technique originally required in situ tissue fixation before excision. Most Mohs micrographic surgeons now use the fresh tissue technique exclusively. Horizontal frozen histologic sections of the excised tumor permit more complete microscopic examination of the surgical margin than traditional methods. Residual tumor is graphically mapped and malignant extensions are pursued with staged excisions until the tumor is removed. Maximum sparing of tumor-free adjacent tissue is achieved with histologic mapping of the tumor boundaries, thus optimizing subsequent wound reconstruction. The history, techniques, indications, cure rates, and current controversies of MMS are reviewed.

Unusual patterns of chronic photodamage through clothing

Recent cancer statistics estimate that the yearly incidence of cutaneous malignancies in the United States is similar to the incidence of all other cancers combined. Ultraviolet radiation-induced photodamage of the skin plays a large role in the growth of these skin cancers. The case of a 47-year-old white man with peculiar patterns of actinic skin damage on the anterior chest and back is presented, and the relationship of these findings with his choice of clothing is reviewed. The transmission of ultraviolet radiation through clothing fabrics is addressed, with recommendations for the use of clothing as an effective form of photoprotection.

Emergency department management of sunburn reactions

The medical records of fifteen patients presenting to the emergency department of a university hospital for sunburn were reviewed. Patients with sunburn had a mean age of 27 years and injury was most likely to occur in July. Six patients had blisters secondary to the ultraviolet injury. Treatment with nonsteroidal anti-inflammatory drugs was used for nine of fifteen patients. Although eight instances of patient education about the primary prevention of future sunburn were documented in the medical records, only one patient record had documentation of her being warned about her increased risk for skin cancer.

Dermatologists' attitudes toward independent nonphysician electrolysis practice

BACKGROUND

Dermatologists' attitudes toward independent electrolysis practice by nonphysicians has historically ranged from the critical to the praiseworthy. It is hypothesized that dermatologists' attitudes toward independent electrolysis practice by nonphysicians is related to physicians' perception of licensing requirements for independent nonphysician electrologists (INE).

METHODS

Nine hundred and thirty-seven fellows of the American Academy of Dermatology (AAD) residing in the Southern United States were anonymously surveyed about independent electrolysis practice by nonphysicians. The results of the survey were analyzed using the Pearson chi-square test.

RESULTS

Dermatologists who perceived that licensing was required for INE were significantly more likely to refer patients to INE for hair removal (P = 0.001) and prescribe EMLA cream (lidocaine 2.5% and prilocaine 2.5%) to patients requesting it for electrolysis performed by INE (P = 0.001). However, those dermatologists who had electrolysis services available in their practice settings (15.1%) were significantly less likely to refer patients to INE (P = 0.001) and to prescribe EMLA cream to patients seeking electrolysis from INE (P = 0.034). Only 5.7% of responding dermatologists supported the use of hair removal lasers by INE.

CONCLUSION

Dermatologists' attitudes toward INE generally appear to be positively related to perceived licensure requirements for INE, but these positive attitudes do not extend to independent laser use by nonphysician electrologists for hair removal.

Mucoepidermoid carcinoma with cutaneous presentation

Mucoepidermoid carcinomas are malignant neoplasms that rarely involve the skin. Composed of both mucus-secreting cells and epidermoid-type cells in various proportions, mucoepidermoid carcinomas occur most commonly in salivary glands. In this case report, we describe a high-grade mucoepidermoid carcinoma with cutaneous involvement. Although this patient was referred for Mohs' micrographic surgery, further evaluation showed either direct or metastatic extension from the parotid gland to skin and distant metastases to the lung and bone. Despite extensive bone involvement, serum levels of ionized calcium, phosphorus, and lactate dehydrogenase remained normal. In view of the widespread metastases, the treatment plan was altered to radiotherapy and chemotherapy instead of surgery. Instructive lessons from this case include the recognition by dermatologists of this rare entity, the importance of a detailed history and complete evaluation of the patient before determining appropriate therapy, and the necessity of individualizing diagnostic tests to a particular patient.