Dermatoblog - Dermatology Blog » Dermatopathology http://www.dermatoblog.com The latest posts and articles from dermatology Mon, 06 Sep 2010 13:34:01 +0000 http://wordpress.org/?v=2.8.5 en hourly 1 What are the most frequent histologic findings in drug eruptions? http://www.dermatoblog.com/2008/12/01/what-are-the-most-frequent-histologic-findings-in-drug-eruptions/ http://www.dermatoblog.com/2008/12/01/what-are-the-most-frequent-histologic-findings-in-drug-eruptions/#comments Mon, 01 Dec 2008 00:03:22 +0000 Dr. Mascaró http://www.dermatoblog.com/2008/12/01/what-are-the-most-frequent-histologic-findings-in-drug-eruptions/ Drug eruptions are a frequent complication seen in approximately 2% to 3 % of hospitalized patients. Some of these eruptions have a characteristic clinical picture such as erythema multiforme, fixed drug eruption, vasculitis, or acute generalized exanthematic pustulosis. However, most patients present with less specific rashes such as morbilliform drug eruptions, or urticaria that can account for up to 95% of cutaneous drug reactions. The diagnosis of drug eruptions is based on clinical history, particularly when the rash is temporally related to the introduction of a new drug, in the last days or weeks. Most drugs that the patient had been taking for years can usually be excluded as triggering agents. In addition, the clinical features of the rash, and, in some cases, the histopathologic examination of a cutaneous biopsy can help in diagnosis.

Although some drug eruptions have histologic patterns that make them easily diagnosed, in most patients histology is ‘‘non-specific’’ or ‘‘non-diagnostic’’. In a study published in the December issue of the Journal of the American Academy of Dermatology the authors have made a revision of the of cutaneous drug eruptions diagnosed over a 5-year period. A total of 104 cases were included in the study. In 83% of the cases, the suspected drug or drugs could be narrowed to 3 or fewer. The two most frequent classes of drug associated with the appearance of a rash were antibiotics (45%) and antiepileptics (15%). 94% of the rashes were morbiliform. Most of the biopsies (80%) showed superficial dermal inflammatory infiltrates in a combined perivascular and interstitial pattern. There were interface changes in 53% of the biopsies. The inflammatory infiltrates was composed of lymphocytes only in 32% of the cases, lymphocytes and eosinophils in 29% of the cases, lymphocytes and neutrophils in 10% of the cases, and lymphocytes, neutrophils and eosinophils in 21% of the cases. Therefore, 50% of the cases contained eosinophils in the infiltrate. In summary, the finding of superficial infiltrates with or without interface changes, with the presence of eosinophils is the most frequent histologic pattern observed in morbilliform drug eruptions.

Cutaneous drug eruptions: A 5-year experience

Gerson D, Sriganeshan V, and Alexis JB.

J Am Acad Dermatol 2008;59:995-9.

Background: The diversity of cutaneous drug eruptions encompasses many clinicopathologic entities.

Methods: Cases with a pathologic diagnosis of drug eruption from 2000 to 2005 were retrieved from our institution. The histologic slides were reviewed, the patterns of inflammatory changes were recorded, and a chart review was performed.

Results: The majority of the cases (94%) were ‘‘morbilliform’’-type rashes. Eighty-two percent of cases exhibited an inflammatory infiltrate confined to the superficial dermis. Eighty percent exhibited a perivascular and interstitial pattern of dermal infiltrate. The infiltrate was composed of lymphocytes and eosinophils in approximately 29% of cases, lymphocytes and neutrophils in approximately 10% of cases, and lymphocytes, eosinophils, and neutrophils in approximately 21% of cases. Eosinophils were present in only 50% of cases. Approximately half (53%) of the cases exhibited epidermal-dermal interface changes.

Limitations: The cases were limited to those with a pathologic diagnosis of cutaneous drug reaction, thereby excluding any cases with drug-induced disease not specifically diagnosed (histologically) as such.

Conclusions: While the histologic features of most drug eruptions are not entirely specific, the finding of superficial infiltrates composed variably of lymphocytes, neutrophils, and eosinophils, either with or without interface changes, should suggest the possibility of a morbilliform drug eruption. Clinical correlation is very helpful to confirm the diagnosis. To our knowledge, this study is the most extensive documenting the histologic findings in morbilliform drug eruptions.

]]> http://www.dermatoblog.com/2008/12/01/what-are-the-most-frequent-histologic-findings-in-drug-eruptions/feed/ 0 Clinical factors predictive of severe histological dysplasia/early melanoma in pigmented lesions excised due to atypia http://www.dermatoblog.com/2007/10/23/clinical-factors-predictive-of-severe-histological-dysplasiaearly-melanoma-in-pigmented-lesions-excised-due-to-atypia/ http://www.dermatoblog.com/2007/10/23/clinical-factors-predictive-of-severe-histological-dysplasiaearly-melanoma-in-pigmented-lesions-excised-due-to-atypia/#comments Tue, 23 Oct 2007 22:21:00 +0000 Dr. Mascaró //2007/10/23/clinical-factors-predictive-of-severe-histological-dysplasiaearly-melanoma-in-pigmented-lesions-excised-due-to-atypia/ The excision of atypical pigmented lesions is a common practice in Dermatology. However, the correlation between clinical and histological atypia is many times poor and lesions that are clinically atypical turn out to be rather unimpressive histologically. Therefore factors that help to predict the probability of these lesions to be truly atypical or malignant can be useful in clinical practice. In this study published in the October issue of the British Journal of Dermatology, a group from Leeds has performed a retrospective study addressed to find what clinical data predicted severe histological dysplasia/early melanoma in excised atypical melanocytic lesions. There where 434 eligible patients with 189 benign melanocytic naevi, 98 with atypical naevi, 19 with Spitz ⁄Reed naevi, 22 blue or congenital naevi, 29 severely dysplastic naevi ⁄in situ melanomas and 77 invasive melanomas. The authors found that old age, history of clinical changes in the lesions, and site on an extremity where predictors of melanoma. An older age was the only predictor predictive of severe histological atypia (or melanoma in situ) compared mild to moderate atypical naevi.

Straus RM, Elliott F, Affleck P, Boon AP, and Newton-Bishop JA.

Br J Dermatology 157: 758–764.

Background Atypical naevi are common benign skin lesions but are also recognized both as precursors of and risk factors for melanoma. It is therefore imperative to excise those lesions that are either likely to progress or are already progressing to melanoma. Clinically, however, it may be difficult to distinguish these from benign atypical naevi with bland histology.

Objectives To analyse the clinical characteristics of excised melanocytic lesions and to identify the predictors of severe histological atypia/melanoma in situ and invasive melanoma.

Methods The case notes of 434 patients who had melanocytic lesions removed at a pigmented lesion clinic were studied retrospectively. A single pathologist reviewed the excised lesions and clinical characteristics predictive of malignancy were identified.

Results The best predictors of melanoma were older age, history of change and site on an extremity, but only older age was predictive of severe histological atypia/melanoma in situ as opposed to mild to moderate atypical histology.

Conclusions These results confirm the difficulty of differentiating accurately between benign atypical naevi and borderline lesions or early melanoma in a clinical setting. It is therefore necessary to have a sufficiently low threshold for excision to avoid missing early melanomas, particularly in older patients presenting with lesions on the extremities.

]]> http://www.dermatoblog.com/2007/10/23/clinical-factors-predictive-of-severe-histological-dysplasiaearly-melanoma-in-pigmented-lesions-excised-due-to-atypia/feed/ 0 Diagnosis of Syphilis in cutaneous biopsies by PCR and Immunohistochemistry http://www.dermatoblog.com/2007/09/15/diagnosis-of-syphilis-in-cutaneous-biopsies-by-pcr-and-immunohistochemistry/ http://www.dermatoblog.com/2007/09/15/diagnosis-of-syphilis-in-cutaneous-biopsies-by-pcr-and-immunohistochemistry/#comments Sat, 15 Sep 2007 09:54:39 +0000 Dr. Mascaró //2007/09/15/diagnosis-of-syphilis-in-cutaneous-biopsies-by-pcr-and-immunohistochemistry/ Syphilis is a sexually transmitted disease that has re-emerged (primary and secondary syphilis in particular) in the late 1990s in western European countries. This is probably due to behavioural changes, probably driven by changes in the HIV epidemic. The diagnosis is usually based on serology, with a combination of nontreponemal and treponemal tests. However, these tests can be negative in early stages, and have low sensitivity and specificity. In addition, many young and middle-aged dermatologists have had relatively little clinical experience with syphilis. This fact can lower the diagnostic suspicion in some cases, and so syphilis serology is not performed. Therefore, new diagnostic tools will be important in the future. In the October issue of the Journal of Investigative Dermatology a group of French investigators studied the detection of Treponema pallidum in macular or maculo papular skin lesions from patients with secondary syphilis by using both PCR and immunohistochemistry with a polyclonal antibody against T. pallidum. The authors found the presence of T. pallidum in 92% of cases, demonstrating a good sensitivity when both techniques are combined.

Diagnosing Treponema pallidum in Secondary Syphilis by PCR and Immunohistochemistry

Buffet M, Grange PA, Gerhardt P, Carlotti A, Calvez V, Bianchi A, Dupin N.

J Invest Dermatol 2007;127:2345–2350.

Epidemiological aspects of syphilis in Western countries have undergone a significant change with respect to the number of cases. Detection of Treponema pallidum is difficult, and the correct diagnosis of secondary syphilis can be critical. In this study, biopsy samples from skin lesions of 12 patients with secondary syphilis were used. Diagnosis of syphilis was based on clinical presentation, dark-field microscope analysis, and serological tests. Using a polyclonal antibody directed against T. pallidum, we show the presence of T. pallidum in 90% of the samples studied with the bacteria located in the epidermis and the upper dermis. The T. pallidum 47-kDa surface protein gene could be amplified by PCR in 75% of the skin lesions. When combining both techniques, T. pallidum was detected in 92% of the samples from patients with secondary syphilis but not in the control samples. Our work suggests that both immunohistochemistry and PCR could be useful for the diagnosis of secondary syphilis and may be helpful in some rare cases when serological assays failed to detect T. pallidum antibodies.

]]> http://www.dermatoblog.com/2007/09/15/diagnosis-of-syphilis-in-cutaneous-biopsies-by-pcr-and-immunohistochemistry/feed/ 0 Stromelysin-3 expression is useful to differentatiate dermatofibroma from dermatofibrosarcoma protuberans http://www.dermatoblog.com/2007/08/31/stromelysin-3-expression-is-useful-to-differentatiate-dermatofibroma-from-dermatofibrosarcoma-protuberans/ http://www.dermatoblog.com/2007/08/31/stromelysin-3-expression-is-useful-to-differentatiate-dermatofibroma-from-dermatofibrosarcoma-protuberans/#comments Fri, 31 Aug 2007 12:22:58 +0000 Dr. Mascaró //2007/08/31/stromelysin-3-expression-is-useful-to-differentatiate-dermatofibroma-from-dermatofibrosarcoma-protuberans/ Dermatofibrosarcoma protuberans (DFSP) is an uncommon locally aggressive spindle-cell neoplasm that frequently recurs and can even produce distant metastases. The diagnosis is based on histology, but in some cases it can be very difficult to differentiate DFSP from the much more frequent benign spindle-cell neoplasm dermatofibroma (DF). Immunohistochemistry can be useful to differentiate between both neoplasms as DFSP are usually CD34 positive and factor XIIIa negative; while DF are usually stain CD34 negative and factor XIIIa positive. However some cases cannot be differentiated with these stains, and therefore new markers would be useful. Stromelysin-3 was recently found to be useful as it would be positive in DF, and negative in DFSP. In this study published in the August issue of the British Journal of Dermatology, a group of Korean researchers studied 23 cases of DF and 17 cases of DFSP. They found that stromelysin-3 was expressed in all cases of DF, and only one case of DFSP was weakly positive. In addition, they found that this immunohistochemical stain had overall a better sensitivity and specificity than CD34 and factor XIIIa for the diagnosis of these spindle cell neoplasms.

Stromelysin-3 expression in the differential diagnosis of dermatofibroma and dermatofibrosarcoma protuberans: comparison with factor XIIIa and CD34

Kim HJ, Lee JY, Kim SH, et al.

Br J Dermatol 2007; 157:319–324

Background
The distinction between dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP) is a well-known challenge for dermatopathologists. Immunohistochemical stains have been used to augment routine histological examination to aid in differentiating DF from DFSP. Stromelysin-3 (ST3) is a member of the matrix metalloproteinase (MMP) family, MMP-11, which is expressed in the skin during wound healing and in the stroma of basal cell carcinoma. Recent studies demonstrated that DFs expressed ST3, whereas DFSPs were only rarely ST3 positive.

Objectives
To assess the expression of ST3 in DF and DFSP and to ascertain whether ST3 is superior to factor XIIIa or CD34 in differentiating DF from DFSP, by comparison with factor XIIIa and CD34 expression.

Methods
Immunohistochemical staining was performed on 23 cases of DF and 17 cases of DFSP, using antibodies to ST3, factor XIIIa and CD34.

Results
ST3 was expressed in all cases of DF (23 of 23) but only one case showed weakly positive staining in DFSP (one of 17). The mean ± SD ST3 immunohistochemistry (IHC) score in DF was 4Æ52 ± 0Æ67. The sensitivity of ST3 was 100% and the specificity was 94%. Factor XIIIa was expressed in all cases of DF (23 of 23) and in five of the 17 DFSPs. The mean ± SD factor XIIIa IHC score in the DFs was 4Æ43 ± 0Æ73. The sensitivity of factor XIIIa was 100% and the specificity was 71%. CD34 was expressed in four of the 23 DFs and 16 of the 17 DFSPs. The mean ± SD CD34 IHC score in the DFSPs was 4Æ41 ± 1Æ37. The sensitivity of CD34 was 94% and the specificity was 83%.

Conclusions
Immunohistochemical staining with a commercial anti-ST3 antibody can be successfully carried out in routine dermatopathology. We confirmed that ST3 is a positive marker for DF and that ST3 staining might be more reliable than factor XIIIa staining in differential diagnosis of DF and DFSP. As the present study showed that ST3 was not absolutely negative in all cases of DFSP, the combination with CD34 immunostaining could make the dis

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