The significance of crystalline/chrysalis structures in the diagnosis of melanocytic and nonmelanocytic lesions.

BACKGROUND: Crystalline/chrysalis structures (CS) are white shiny streaks that can only be seen with polarized dermatoscopy. OBJECTIVES: We sought to estimate the prevalence and assess the clinical significance of CS in melanocytic and nonmelanocytic lesions. METHODS: This was a prospective observational study in which dermatoscopic assessment of lesions was recorded in consecutive patients examined during a 6-month period. In addition, a data set of biopsy-proven melanomas was retrospectively analyzed. RESULTS: In all, 11,225 lesions in 881 patients were prospectively examined. Retrospectively, 229 melanomas imaged with polarized dermatoscopy were analyzed. In the prospective data set, a median of 12.7 lesions (range, 1-54) were evaluated per patient. None of clinically diagnosed Clark nevi (n = 9750, 86.8%) demonstrated CS. Overall, CS were observed in 206 (1.8%) lesions, most commonly dermatofibromas and scars among nonbiopsied lesions. A total of 265 (2.4%) lesions were biopsied, including 20 melanomas and 36 nevi. Among biopsied malignant lesions, CS were most commonly observed in basal cell carcinoma (47.6%) and invasive melanomas (84.6%). Melanomas were more likely to have CS than biopsied nevi (odds ratio = 9.7, 95% confidence interval 2.7-34.1). In the retrospective data set, CS were more commonly observed among invasive melanomas (41%) compared with in situ melanomas (17%) (odds ratio = 3.4, 95% confidence interval 1.9-6.3, P < .001). The prevalence of CS correlated with increased melanoma thickness (P = .001). LIMITATIONS: Biopsied lesions represent a small percentage of the total number of lesions evaluated. CONCLUSION: Among biopsied malignant lesions, CS are most commonly observed in basal cell carcinoma and invasive melanomas and rarely seen in nevi. In melanoma, CS may reflect increased tumor thickness and progression.

Lentigo maligna in a young adult.

BACKGROUND: Lentigo maligna is mainly diagnosed in the elderly with severely sun-damaged skin. OBSERVATION: We describe a case of lentigo maligna in a 51-year-old woman with Fitzpatrick skin type III. Based on private photographs of the patient, we were able to ascertain that the lesion was already present at the age of 22 years. Despite the 29-year clinical history, the lesion was still entirely intraepidermal on histologic examination. CONCLUSION: Lentigo maligna in young adults is extremely rare, and therefore represents a diagnostic challenge for both clinicians and histopathologists.

Never perform laser treatment of skin tumors with clinical "EFG" criteria.

Laser treatment is a common procedure for the treatment of cosmetically troubling skin lesions but has the limitation that histopathologic diagnosis is usually not obtained prior to treatment. Laser treatment of melanomas with benign clinical features may delay or make more difficult the correct diagnosis of such tumors. A helpful tool to identify clinically innocent appearing melanomas is the "EFG" rule, summarizing the common clinical features as "elevated, firm skin lesions showing continuous growth". We report a 42-year-old woman who presented with a recurrent and metastatic melanoma after laser treatment of a tumor which was apparently clinically innocent and highlight the clinical features of such benign-looking melanomas.

Nevus type in dermoscopy is related to skin type in white persons.

BACKGROUND: Dermoscopic classification of acquired melanocytic nevi (AMN) is based on the evaluation of 3 main criteria-global pattern, pigment distribution, and color. OBJECTIVE: To determine whether these features are different in AMN in white people with different skin types (STs) according to the Fitzpatrick classification. DESIGN: Digital dermoscopic images of AMN were evaluated, and the correlation of the 3 main dermoscopic criteria with patient ST was analyzed. SETTING: Consecutive patients were recruited from 7 pigmented lesion clinics between June 1, 2004, and June 30, 2005. Patients For each patient, the ST (I [always burns, never tans] to IV [rarely burns, tans with ease]) was scored, and 1 representative AMN (defined as the AMN showing a dermoscopic typology that is repeatedly seen in the same patient) was selected and photographed. MAIN OUTCOME MEASURES: The distribution of the dermoscopic criteria of AMN in patients with different STs was calculated by univariate analysis. Differences in prevalence were tested using the chi(2) test. The correlation between dermoscopic criteria and ST, adjusted for age, sex, and enrolling center, was evaluated by calculating odds ratios and 95% confidence intervals by logistic regression analysis. RESULTS: Of 680 included patients, dermoscopic analysis revealed significant differences in the prevalent nevus pattern in the 4 ST groups. Light brown AMN with central hypopigmentation were associated with ST I, and ST IV was associated with the so-called black nevus (P<.001), typified by reticular pattern, central hyperpigmentation, and dark brown coloration. A significant association was also found between multifocal pattern and ST II and ST III. CONCLUSIONS: The dermoscopic nevus type varies according to different ST in white people. This knowledge may have an effect on obtaining for biopsy lesions that exhibit unusual dermoscopic patterns when patient ST is considered.

Dermoscopy patterns of fibroepithelioma of pinkus.

BACKGROUND: Fibroepithelioma of Pinkus (FeP) is a rare variant of basal cell carcinoma that may clinically mimic a number of benign skin tumors. While the dermoscopic features of basal cell carcinoma have been studied extensively, little is known about the dermoscopic features of FeP. OBSERVATIONS: Retrospective evaluation of clinical records and digital clinical dermoscopic images of 10 histopathologically proved FePs (6 nonpigmented and 4 pigmented) was performed. Clinically, no FeP was correctly identified and, in half of all patients, a clinical differential diagnosis of purely benign skin lesions was made. Dermoscopy enabled the correct diagnosis in 9 of 10 FePs, based on the presence of fine arborizing vessels, either alone or associated with dotted vessels, and white streaks (in 100%, 70%, and 90% of lesions, respectively). In the 4 pigmented FePs, a structureless gray-brown area of pigmentation and variable numbers of gray-blue dots were observed, in addition. CONCLUSIONS: Dermoscopy is helpful in diagnosing FeP and in differentiating this variant of basal cell carcinoma from other benign skin tumors commonly included in the clinical differential diagnosis. This presumes, however, that dermoscopy is used as a first-line examination for all skin lesions, not only for those that are clinically suspect.

Slow-growing melanoma: Report of five cases.

BACKGROUND: Epidemiologic data on melanoma reveal a considerable increase in incidence, especially of the early forms (melanoma in situ and early invasive melanoma), but the mortality rates are relatively stable. These data suggest the hypothesis of the existence of a melanoma with less aggressive biological behaviour. This hypothesis is, however, hard to be proven if the assumption is true that more and less aggressive melanomas very often exhibit overlapping clinical and histopathologic features. Digital dermoscopic imaging techniques permit today a detailed documentation of lesions over time and, therefore, represent an optimal tool to disclose the natural evolution of a given lesion. We present five case of slow-growing melanomas observed during a long-term period of follow-up. MAIN OBSERVATION: Five pigmented skin lesions from five patients with multiple atypical melanocytic nevi were examined at the baseline consultation and digital pictures were taken for monitoring purposes. The lesions have been followed-up for a long time because of the absence of significant changes over time. After a variable period of follow-up (1 to 10 years) all lesions were finally removed and subsequent histopathologic examination revealed early stage melanoma in all cases. CONCLUSION: Dermoscopy and digital follow up might be the key factors to improve the knowledge about the natural evolution of nevi and melanoma and the spectrum of undefined melanocytic proliferations.