The impact of in vivo reflectance confocal microscopy on the diagnostic accuracy of lentigo maligna and equivocal pigmented and nonpigmented macules of the face.

Limited studies have reported the in vivo reflectance confocal microscopy (RCM) features of lentigo maligna (LM). A total of 64 RCM features were scored retrospectively and blinded to diagnosis in a consecutive series of RCM sampled, clinically equivocal, macules of the face (n=81 LM, n=203 benign macules (BMs)). In addition to describing RCM diagnostic features for LM (univariate), an algorithm was developed (LM score) to distinguish LM from BM.

Subungual melanoma: a study of 124 cases highlighting features of early lesions, potential pitfalls in diagnosis, and guidelines for histologic reporting.

Subungual melanoma (SUM) is an uncommon variant of melanoma that is often difficult to diagnose, both clinically and pathologically. In an attempt to provide pathologic clues to diagnosis, especially in early lesions or small biopsies, and to provide practical advice to pathologists in reporting, the clinicopathologic features of 124 cases of SUM were reviewed, the largest series reported to date. The features of 28 cases of subungual melanoma in situ (MIS), comprising 4 cases of MIS and 24 cases where areas of MIS were present adjacent to dermal-invasive SUMs, were compared with those of a similar number of acral nevi to identify useful distinguishing features.

Low prevalence of RAS-RAF-activating mutations in Spitz melanocytic nevi compared with other melanocytic lesions.

Melanocytic lesions, including Spitz nevi (SN), common benign nevi (CBN) and cutaneous metastatic melanoma (CMM), were analyzed for activating mutations in NRAS, HRAS and BRAF oncogenes, which induce cellular proliferation via the MAP kinase pathway. One of 22 (4.5%) SN tested showed an HRAS G61L mutation.

Dermoscopy and its role in diagnosing melanocytic lesions: a guide for pathologists.

Dermoscopy (surface microscopy) is a clinical technique which uses a hand-held magnifying instrument, usually with liquid at the skin-instrument interface, to examine pigmented lesions on the skin surface. A magnification of x 10 is usually used. Dermoscopy assists in deciding if the lesion should be excised or biopsied, requires monitoring or can be safely left in situ.

UV light from 290 to 325 nm, but not broad-band UVA or visible light, augments the formation of melanocytic nevi in a guinea-pig model for human nevi.

We have previously described a guinea-pig model where pigmented nevi similar to human nevi can be produced by application of low-dose topical 7,12-dimethylbenzanthracene (DMBA) followed by solar-simulated light. Five groups of guinea-pigs were used to test the effect of various spectral bands of solar-simulated light on low-dose DMBA-induced melanocytic nevi. Animals were irradiated with either UVB to near UVA2 (290-325 nm), UVA, visible light, full solar spectrum or no irradiation three times per wk for 12 mo to determine the broad-band effect of nevi-inducing irradiation.

Use of multiple cytometric markers improves discrimination between benign and malignant melanocytic lesions: a study of DNA microdensitometry, karyometry, argyrophilic staining of nucleolar organizer regions and MIB1-Ki67 immunoreactivity.

Confident separation of benign naevi and malignant melanoma can sometimes be very difficult using conventional microscopy. This study evaluated the combined diagnostic abilities of multiple cytometric markers in separating various types of naevi from melanomas. The lesions studied included 27 benign compound naevi, 20 dysplastic naevi, 10 Spitz naevi and 24 melanomas.

Autonomous histopathological regression of primary tumours associated with specific immune responses to cancer antigens.

Spontaneous histopathological regression of cancer has been reported. The involvement of the immune system in such regression has been advocated, leading to the theory of immunological surveillance against cancer. A prediction of this theory is that common tumour antigens can be recognized upon repeated exposure by cell-mediated immunity, which leads to tumour regression and the subsequent appearance of tumour antigen-loss variants.

Argyrophilic staining of nucleolar organizer region count and morphometry in benign and malignant melanocytic lesions.

Differentiation between malignant melanomas (MMs) and benign nevi based on histologic features can sometimes be difficult. This study evaluated the diagnostic effectiveness of argyrophilic staining of nucleolar organizer regions (AgNORs) in separating benign nevi from MMs by assessing 27 compound nevi (CN), 20 dysplastic nevi (DN), 10 Spitz nevi (SN), and 24 MMs. Both AgNOR count and morphology variables were measured from the superficial, middle, and deep zones of the lesions using video image analysis.

Differentiating benign nevi from malignant melanoma using DNA microdensitometry and karyometry and maturation: a zonal comparison, correlation and multivariate analysis.

Objective: To evaluate the diagnostic effectiveness of cytometric features of DNA microdensitometry, karyometry (nuclear morphometry) and maturation and their combinations in separating benign nevi from malignant melanomas.

Study Design: Tumor cells were measured from each of the superficial, middle and deep zones of 81 melanocytic lesions using video image analysis for nuclear DNA content, chromatin compactness, and nuclear size and shape variables. There were 27 banal compound melanocytic nevi, 20 dysplastic compound nevi, 10 Spitz nevi and 24 malignant melanomas (MM).

Melanin bleaching in argyrophilic staining of AgNORs in pigmented lesions: a morphometric evaluation.

Objective: To establish a procedure that can effectively bleach melanin from pigmented lesions without affecting quantification of argyrophilic staining of nucleolar organizer regions (AgNORs).

Study Design: Twenty banal compound nevi, five from each of nonpigmented, slightly pigmented, moderately pigmented and heavily pigmented groups, were bleached by 10% H202 for periods of 0 (nonbleached controls) and 24 hours. AgNOR size and count parameters of nevomelanocytic nuclei were measured by video image analysis.

Spitz naevus versus Spitzoid melanoma: when and how can they be distinguished?

Spitz naevus is a benign melanocytic lesion that shares many histological features with melanoma. While Spitz naevi characteristically occur in children and young adults and melanomas in the middle-aged and elderly, either tumour can occur in patients of any age. In many cases, the histopathological diagnosis of Spitz naevus is straightforward, particularly in small lesions displaying many or all of the typical histological features and occurring in young patients.