Histologic mimics of malignant melanoma

Although spongiotic (eczematous), psoriatic and cutaneous skin infections are among the most common in dermatology consultations, melanocytic lesions - including the different types of nevi and melanomas - are among those that cause a great deal of concern and stress to patients and their clinicians. A diagnosis of benign melanocytic nevus carries a very good prognosis. However, a diagnosis of melanoma might indicate more aggressive treatment, lifelong surveillance and a worse prognosis. Differentiating between these conditions is not always a straightforward process for clinicians and pathologists. Therefore, knowledge of melanoma mimickers is very important for clinicians in general, and dermatologists and pathologists in particular. In this review, we called attention to some of the more frequent benign but unusual melanocytic lesions that are of diagnostic concern for clinicians evaluating these cutaneous proliferations.

Immunohistochemical Double Staining of Ki-67/Melan-A in Melanocytic Nevi and Malignant Melanomas / 대한피부과학회지

BACKGROUND: Melanomas need to be differentiated from benign melanocytic lesions during diagnosis. However, it is difficult to differentiate them using histopathology alone, since both neoplasms have broad morphological spectrums and subtle differentiating features. OBJECTIVE: To evaluate the usefulness of Ki-67/Melan-A double staining for differentiating melanoma from benign melanocytic nevi. METHODS: We selected 20 cases of intradermal nevi, 20 cases of compound nevi, 5 cases of dysplastic nevi, and 25 cases of melanoma from clinicopathologically proven cases reviewed by the Department of Dermatology at our medical center. Ki-67/Melan-A double staining was performed, and the Melan-A verified Ki-67 index (Ki-67-M index) and Ki-67 index were measured. The immunopositivity was measured in the deepest third of the lesions. RESULTS: The Ki-67-M index of intradermal nevi, compound nevi, dysplastic nevi, and melanoma were 0.4+/-0.9%, 1.0+/-1.1%, 4.3+/-1.7%, and 24.1+/-10.9%, respectively. The best Ki-67/Melan-A cut-off point to distinguish melanomas from benign melanocytic nevi was 5%; the sensitivity and specificity were 100% and 97.7%, respectively. Immunopositivity in the deepest third of the intradermal nevi, compound nevi, and melanoma, were 10.5%, 20%, and 100%, respectively; the sensitivity and specificity for diagnosing melanoma were 100% and 84.6%, respectively. The sensitivity and specificity of combined Ki-67-M and immunopositivity in the deepest third for diagnosing melanoma were 100% and 97.7%, respectively. CONCLUSION: The Ki-67-M index and immunopositivity in the deepest third of melanoma were significantly higher than that of benign melanocytic nevi. Therefore, Ki-67/Melan-A double staining is a potentially valuable diagnostic tool for differentiating melanoma from benign melanocytic nevi.

The Effect of Intense Pulsed Light Treatment on the Epidermal Melanocytic Lesions / 대한피부과학회지

BACKGROUND: Intense pulsed light(IPL) systems are high intensity pulsed sources which emit noncoherent, defocused, polychromatic light in a broad wavelength spectrum of 400-1200nm. The mechanism of action of such light systems corresponds to the selective photothermolysis.Nowdays, IPL system widely used in dermatologic field such as unwanted hair removal, epidermal melanocytic lesions, vascular lesions, and photorejuvenation OBJECTIVE: The purpose of this study was to evaluate the clinical results of diverse epidermal melanocytic lesions after treatment with an IPL source. METHOD: Twenty patients with epidermal melanocytic lesions were enlisted. IPL treatment was administered to the patients in a 4-week sessions. Irradiation wavelength was controlled using cutoff filters ranging from 400 to 700nm, with a fluence of 10-13.5J/cm2 with double pulse illumination and a pulse width of 7msec. RESULTS: By the end of the study, three attending physicians assessed the results for 85% of the subjects as excellent or good, with 85% of the patients reporting that same results; however, deep lesion such as Becker's nevus showed an average clearance of fair. No specific adverse effects except two case of blisters were observed after treatment. CONCLUSION: Treatment of epidermal melanocytic lesions in Asian skin using IPL is an effective, safe, and rapid treatment, with relatively few side effects and high patient satisfaction.

Immunoreactivity of Epidermal Growth Factor Receptors in Melanocytic Lesions / 대한피부과학회지

BACKGROUND: Epidermal growth factor receptors (EGFR) have been reported to be absent in melanomas. But recently, the presence of EGFR on melanocytic cells was reported to be a marker of malignant transformation. OBJECTIVE: Our purpose was to investigate the presence of EGFF in melanocytic lesions and to determine whether EGFR presence correlates with the potential or malignant transformation of melanocytic cells. METHODS: We performed the immunohistochemical studies to reveal immunoreactivity of EGFR in 7 compound nevi, 10 intradermal nevi, and four melanomas using the Vectastain ABC immunoperoxidase stain system. RESULTS: Although the intensity of staining was slightly variable, all melanocytic cell types in the studied lesions of compound nevi, intradermal nevi, and melanoms had immunoreactive EGFR. Intense staining far EGFR of all nucleated layers of keratinocytes overlying a melanocytic lesion was also seen. But in the melanoma cells, the staining intensity was modarately deereased. CONCLUSION: Although we found no correlation of EGFR with the potential for malignancy in melanocytic lesions, the high level of expression within nevocytes and lesional keratinocytes suggests EGFR or transforming growth factor a, by acting through the EGFR, plays a role in the pathogenesis, maintenance, or evolution or these lesions.