Search

Background: Diagnosis of fibrous tumors can be challenging and expensive due to the use of special stains., Objective: Determine the usefulness of fluorescence microscopy in the evaluation of elastic tissue patterns on hematoxylin-eosin-stained slides., Methods: In total, 228 slides representing different fibrous tumors were evaluated for their elastic tissue patterns by fluorescence microscopy, and sensitivity and specificity were determined for relevant comparisons., Results: Fluorescence microscopy was found to be useful, especially for distinguishing dermatofibroma from dermatofibrosarcoma protuberans and dermatomyofibroma from other fibrous tumors., Limitations: In some cases, excessive background staining made patterns difficult to interpret., Conclusion: Evaluation of elastic tissue patterns by fluorescence microscopy in fibrous tumors is a cheap and efficient means to further delineate these often challenging tumors., (Copyright © 2018 American Academy of Dermatology, Inc. All rights reserved.)

Background: The histopathologic features of tinea vary widely and its diagnosis could be easily missed if the index of suspicion is not high. We aimed in this study to detect histopathologic features that could be a clue for diagnosis, Methods: We retrospectively reviewed 103 cases of tinea, confirmed by Periodic acid-Schiff (PAS) staining. For each case, gender, biopsy site, and pre-biopsy suspicion were recorded. The presence or absence of 17 microscopic features was noted., Results: Concordance between pre-biopsy and histopathologic diagnosis was noted in 57.28% of cases, suggesting that the diagnosis is often not suspected clinically. Among the histopathologic features studied, a compact stratum corneum (either uniform or forming a layer beneath a basket weave stratum corneum), parakeratosis, mild spongiosis and neutrophils in the stratum corneum and within the blood vessels were the most frequent features noted., Conclusion: This study suggests histopathologic clues that should prompt the pathologist to order a PAS stain, especially when diagnosis is not suspected clinically., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Alterations in dermal collagen are noted in dermatofibroma, dermatofibrosarcoma protuberans, morphea, lichen sclerosus et atrophicus, hypertrophic scars, and keloids. The authors sought to determine whether variations in birefringence of collagen by polarized microscopy could be of help in diagnosing such conditions. Representative hematoxylin and eosin sections of 400 cases, including dermatofibroma, dermatofibrosarcoma protuberans, hypertrophic scars, keloid, morphea, and lichen sclerosus, were examined under polarized microscopy. Distinct patterns of birefringence of collagen for each disease were noted under polarized microscopy. This study highlights the use of polarized microscopy as adjunctive tool in differentiating different diseases with collagen alteration.

The skin biopsy pathway involves numerous communication requirements, technical events, human handoffs, and cognitive decisions. Every step in the process has an error rate >0. To deliver the highest quality care, dermatologists obtaining skin biopsy specimens should implement systems in their office to minimize errors. This includes the prevention of wrong-site surgery, which in most instances involves accurate communication of the correct biopsy location to the performing surgeon. Part II of this continuing medical education article presents techniques for assessing and planning improvement to the skin biopsy pathway in your office, and provides a simple online quality improvement activity that allows Board-certified dermatologists the opportunity to potentially improve aspects of the skin biopsy process in their own practices, and in the process obtain Maintenance of Certification credit., (Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Misdiagnosis may result from biopsy site selection, technique, or choice of transport media. Important potential sources of error include false-negative direct immunofluorescence results based on poor site selection, uninformative biopsy specimens based on both site selection and technique, and spurious interpretations of pigmented lesions and nonmelanoma skin cancer based on biopsy technique. Part I of this 2-part continuing medical education article addresses common pitfalls involving site selection and biopsy technique in the diagnosis of bullous diseases, vasculitis, panniculitis, connective tissue diseases, drug eruptions, graft-versus-host disease, staphylococcal scalded skin syndrome, hair disorders, and neoplastic disorders. Understanding these potential pitfalls can result in improved diagnostic yield and patient outcomes., (Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Stem cells generate great interest because they hold the promise for treatment of various incurable diseases. Several distinct stem cell populations have been identified in each organ, including the skin. As the skin is the largest organ in the body and is easily accessible, cutaneous stem cells have raised significant hopes for being a rich source of easily available multipotent stem cells. Genetic alterations and mutations in stem cells are being proposed as initiation step in multiple cancers. Small populations of oncogenic stem cells termed as cancer stem cells or tumour-initiating cells have been identified in multiple tumours, including squamous cell carcinomas, and melanomas that can sustain tumour growth, underlie its malignant behaviour and initiate distant metastases. These cells are controlled and regulated by the same pathways that are also responsible for maintenance and differentiation of normal stem cells. Developing a targeted therapy against the oncogenic stem cells and dysregulated members of the signalling pathways may be the key to understanding and treating skin cancers like melanomas, for which we still do not have an effective treatment., (© 2013 European Academy of Dermatology and Venereology.)

Keratoacanthoma (KA), an epithelial neoplasm occurring in sun-exposed skin of the elderly, is considered a well-differentiated form of conventional squamous cell carcinoma (SCC) that often follows a course of spontaneous regression. Distinguishing KA from conventional SCC or pseudocarcinomatous epithelial hyperplasia ensures proper diagnosis, treatment and management. For some time, perforating elastic fibers have been utilized in differentiating KA from SCC. This phenomenon may also occur in association with scars and hypertrophic lupus erythematosus (LE). To assess the diagnostic utility of perforating elastic fibers, we compared their incidence in KA, SCC, scars with overlying pseudocarcinomatous hyperplasia, hypertrophic LE, hypertrophic lichen planus (LP) and lichen simplex chronicus (LSC). A retrospective case search identified 359 lesions and the presence of perforating elastic fibers was evaluated using routinely stained sections. This phenomenon was documented in all studied groups except hypertrophic LP. The incidence was found to be 71% in KA, 37% in SCC, and was lowest in inflammatory conditions with associated pseudocarcinomatous hyperplasia (hypertrophic LP 0%, hypertrophic LE 5.9% and LSC 28.2%). The observed frequency in pseudocarcinomatous hyperplasia overlying scars (57.8%) vs. KA (71%) was not statistically different. Although elastic fiber trapping has potential value as a diagnostic criterion for KA, dermatopathologists should consider its limitations. Its diagnostic utility was greatest in distinguishing KA from hypertrophic LE and hypertrophic LP. Conversely, elastic trapping is not helpful differentiating pseudocarcinomatous hyperplasia from recurrent/persistent KA following surgery., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The correct identification of vessel type is crucial in distinguishing cutaneous polyarteritis nodosa from superficial thrombophlebitis. As the treatment and prognosis of these conditions are very different, correct diagnosis is critical, but they have overlapping clinical and histopathologic features, which can sometimes make the distinction difficult. Features commonly used to distinguish an artery from vein include vessel shape and diameter, the presence or absence of an internal elastic lamina, smooth muscle pattern, and the presence or absence of valves. Recently, it has been proposed that the amount and distribution of elastic fibers in the medial muscular layer are the most reliable features to make this distinction. The first part of this study used prosector-identified vessels to determine which of these features is most sensitive and specific for identifying an artery and vein. A total of 19 arteries and 16 veins were dissected from autopsy and amputation specimens. For each specimen, the smooth muscle pattern, elastic fiber pattern, the presence of valves, and the presence or absence of an internal elastic membrane were determined. The quantity of elastic fibers in the muscular wall of each sample was also determined. Although the elastic fiber pattern was the most specific feature in identifying a vein, it suffered from low sensitivity (43.8%). The smooth muscle pattern had the highest combined sensitivity and specificity. In the second part of this study, the histologic features listed above were examined in previously diagnosed cases of superficial thrombophlebitis and arteritis. When inflammation is present within and around the wall of the vessel, all of the studied histologic features become less reliable, and the interobserver reliability of distinguishing arteritis from thrombophlebitis was low. Our findings suggest that no single histopathologic feature is completely reliable and combining the histopathologic features with clinicopathologic correlation is essential for correct vessel identification.

A 45-year-old woman presented for evaluation of a solitary pruritic nodule on the abdomen that suddenly appeared 3 weeks before. She was healthy without a significant medical history, travel history, exposures, medications, or pets. She reported that she consumed sushi at least weekly in the city of San Francisco. A punch biopsy revealed a superficial and deep perivascular and interstitial infiltrates consisting of lymphocytes, plasma cells, and many eosinophils. Most notably, there was a parasite centered in the reticular dermis with prominent lateral chords, a well-developed muscular esophagus, and an intestine that contained a brush border and multinucleate cells. Evaluation of these histological sections by the Centers for Disease Control and Prevention determined the parasite to be a nematode of the genus Gnathostoma. The patient underwent a systemic work-up for gnathostomiasis, including imaging, and no other abnormalities were found. She completed a 3-week course of albendazole and has remained asymptomatic since the biopsy of her abdominal lesion. Although gnathostomiasis is often a systemic illness, this patient did well with apparently only localized cutaneous disease. Gnathostomiasis should be considered in patients who present with nonspecific papules and nodules, especially when there is a history of frequent consumption of raw fish.

Objective: To ascertain whether a dose response exists between the dose of brown recluse spider venom (BRSV) and the cutaneous and coagulation effects in a rabbit model. Cutaneous necrosis is a serious complication of brown recluse spider envenomation (spider bite with venom). Disseminated intravascular coagulation (DIC) is a dreaded complication of brown recluse envenomation in humans. New Zealand white (NZW) rabbits have proved to be a model for the study of therapeutic regimens to prevent skin necrosis after spider bites. We studied the venom's effects on the skin and the coagulation mechanism in this rabbit model to determine if a clear dose-response relationship could be established. Establishment of a dose-response relationship is an important first step in determining if the NZW rabbit is a suitable model to study both cutaneous and systemic effects of the venom., Design: Thirty-six NZW rabbits were divided into three groups. One group received a saline injection, and the other two groups received a 4.0 microg or a 10.0 microg dose of purified BRSV intradermally into the skin on the dorsum of the back., Methods: Blood was collected at baseline, 24, 48, and 72 hours. Tissue specimens were obtained after seven days during the animal necropsy and gross and microscopic pathology examination was conducted to assess tissue damage. Measurements included complete blood count (CBC); platelets; PT; activated partial thromboplastin time (APTT); fibrinogen (clottable, immunological); coagulation factors II, V, VII, VIII, IX, X, XI, XII; anti-thrombin (AT); alpha-2 antiplasmin (AP); Protein C (PC); mixing studies; lupus anticoagulant screening; plasminogen; thrombin-antithrombin; fibrin degradation products (FDP); d-dimer; and thrombin time., Results: Gross pathology results were consistent with previous studies that used higher doses of BRSV. The WBC and platelet counts decreased at 24 hours in the two groups receiving the BRSV (p < 0.05). BRSV produced a dose related prolongation in the APTT (p < 0.05). Levels of fibrinogen as well as factors V, VII, VIII, IX, X, AT, and AP (p < 0.05) were increased in response to the BRSV. Protein C decreased at 24 hours (p < 0.05) and remained low in other time points. Mixing studies corrected the prolonged APTTs to normal ranges. Factor IIXI and XII showed no significant alteration in response to the BRSV., Conclusions: In the model, both the size and depth of the eschar were dose-related. We also observed a dose related elevation in the APTT that corrected with mixing studies. The dose-response relationship suggests direct interference by a component of the venom, rather than an idiosyncratic response. We did not detect a deficiency of commonly measured coagulation factors or evidence of a lupus anticoagulant. Protein C demonstrated a decrease. Although DIC did not occur in this rabbit model, a dose-related elevation in APTT was noted. The finding that the elevation corrected with mixing studies suggests that a plasma factor is essential in the coagulopathy associated with brown recluse envenomation. Further studies to identify this factor could shed light on human coagulopathy following envenomation.

Petrolatum rarely causes hypersensitivity reactions. We report a case of a 51-year-old white man with allergic contact dermatitis due to white petrolatum on damaged skin. The patient, who presented with a history of hand dermatitis and intolerance to ointments for years, was patch-tested with white petrolatum on scratched skin. Patch tests with the European Standard series, preservatives, steroids, vehicles, and emulsifiers were also performed. The patch-test reaction to white petrolatum on scratched skin was positive at 48 and 96 hours. All other patch-test results were negative.

Basaloid follicular hamartoma is an uncommon neoplasm with distinctive histopathological findings. It presents as four distinctive clinical forms: a solitary papule, a localized plaque of alopecia, a localized linear and unilateral type, and generalized papules with associated alopecia and myasthenia gravis. Histologically, basaloid follicular hamartomas are characterized by thin branching strands and thick cords of basaloid or squamoid cells extending from a follicle into a loose, fibrillar, fibrocytic or mucinous connective tissue stroma. We report a case of long-standing, generalized basaloid follicular hamartomas associated with acrochordons, seborrhoeic keratoses, and a history of chondrosarcoma. In general, solitary tumours are sporadic; multiple tumours are inherited and frequently associated with a syndrome. Further surveillance is warranted to determine if the association of multiple basaloid follicular hamartomas and chondrosarcoma constitutes an inherited syndrome.

Tinea nigra is a relatively uncommon dermatiaceous fungal infection, usually caused by Phaeoannellomyces werneckii, that may mimic a melanocytic lesion. We describe the value of epiluminescent dermoscopy of tinea nigra plantaris compared with other common diagnostic tools and procedures available (clinical appearance, potassium hydroxide [KOH], culture, culture mount preparation, and biopsy). A case of tinea nigra plantaris was evaluated clinically, microscopically with KOH, and dermatoscopically. Dermatoscopic findings were evaluated according to the Stolz system. Dermoscopy, clinical presentation, and microscopy with KOH all confirmed the diagnosis, with dermoscopy being the fastest and simplest procedure. Dermoscopy is a useful clinical adjuntive tool in differentiating tinea nigra from a melanocytic lesion.

Histologic specimens from 41 rabbits were studied for changes resulting from the manual injection of brown recluse spider venom. Major findings included a mixed inflammatory cell infiltrate, coagulative tissue necrosis, and vasculitis. All specimens demonstrated a well-delineated zone of eosinophilic staining recognizable as "mummified" coagulative necrosis of the epidermis and dermis. A dense band of neutrophils bordered the zone of necrosis. Immediately adjacent to the neutrophilic band, small vessel vasculitis was a universal finding. Degranulated eosinophils and neutrophils and macrophages filled with eosinophilic granules were common. Inflammatory foci were often centered on groups of lipocytes within the dermis. Large vessel vasculitis resembling that seen in polyarteritis nodosa was present deep to 7 of the 40 eschars. Large vessel vasculitis may contribute to the large zones of necrosis seen after some brown recluse spider bites. Eosinophils may play a role in tissue damage after envenomation.