Appropriately trained and experienced histopathologists can assess prognostically important features of melanomas accurately and reproducibly. Given our recent finding of the significance of TMR in determining prognosis, it is important that this feature be assessed by a standardized method and documented for all primary cutaneous melanomas.

This large, single-center study confirms that patients with a negative SNB have a significantly better prognosis than those with positive SNs. In those with a negative SNB, primary tumor thickness and ulceration are independent predictors of survival. Incorrect pathologic diagnosis contributed to only a minority of the false-negative results in this study.

Differentiation between malignant melanomas and benign nevi can sometimes be difficult by conventional histopathology, and additional diagnostic markers may be helpful. This study investigated the immunoreactivity of the cell proliferation marker MIB1-Ki67 in 23 compound nevi, 17 dysplastic nevi, 8 Spitz nevi (SN), and 24 malignant melanomas (MMs) and evaluated its ability in separating benign nevi from MMs. In each lesion, the average number (percentage) of MIB1-positive nuclei (%MIB1-Mean) and the maximal number (percentage) of MIB1-positive nuclei (%MIB1-Max) were determined from each of the superficial, middle, and deep dermal zones of the lesion as well as from the entire lesion. The %MIB1-Max was determined from subjectively selected area(s) of high count. Malignant melanomas had a significantly greater %MIB1-Mean and %MIB1-Max than all benign nevi in all individual zones and in the entire lesion (p < 0.05). Discriminant analysis showed that the %MIB1-Mean and %MIB1-Max counted from the whole lesions had better discriminating abilities than from the individual zones. By using the %MIB1-Mean from all zones, all lesions except 1 SN and 3 MMs could be correctly classified as benign or malignant. When using the %MIB1-Max from all zones, all but 2 SN could be correctly separated as benign or malignant. Thus, MIB1-Ki67 immunoreactivity closely correlates with the benignancy or malignancy of melanocytic lesions and may assist in the differentiation of benign nevi from MMs.

An FN SN can occur because of deficiencies in nuclear medicine, surgery, or pathology. qRT can detect "occult" metastatic melanoma in SNs that have been identified as negative by histopathology.

A sentinel lymph node (SLN) that is melanoma negative by pathologic examination implies absence of melanoma metastasis to that regional lymph node field. However, a small proportion of patients develop regional node field recurrence after a negative SLN biopsy. In this study, we reviewed the histopathology of negative SLNs from such patients to determine whether occult melanoma cells were present in the SLNs, to characterize the pathologic features of false-negative SLNs, and to provide recommendations for the histopathologic examination of these specimens. Between March 1992 and June 2001, of 1152 patients who had undergone SLN biopsy for primary melanomas at the Sydney Melanoma Unit, 976 were diagnosed with negative SLNs by initial pathologic examination (using 2 hematoxylin and eosin stained sections, and 2 immunostained sections for S-100 protein and HMB45), and follow-up was available in 957. Of these, 26 (2.7%) developed regional lymph node recurrence during a median follow-up period of 35.7 months. For 22 of them, the original slides and tissue blocks were available for reexamination. The original slides of each block were reviewed. Multiple further sections were cut from each block and stained with hematoxylin and eosin, for S-100, HMB45, and Melan A. Deposits of occult melanoma cells were detected in 7 of the 22 cases (31.8%). In 5 of the 7 cases, deposits of melanoma cells were present only in the recut sections. There were no significant differences in clinical and pathologic variables for those patients in whom occult melanoma cells were found by pathologic reexamination of their SLNs, compared with those in whom no melanoma cells were detected. The detection of melanoma cell deposits in only 7 of 22 false-negative SLNs suggests that mechanisms other than failure of histopathologic examination may contribute to the failure of the SLN biopsy technique in some patients. The failure rate for melanoma detection in SLNs by our routine pathologic examination, using the current protocol at our institution, was <1% (7 of 957 patients). Routinely performing more intensive histopathologic examination of SLNs is difficult to justify from a cost benefit perspective; we therefore recommend examining two hematoxylin and eosin stained sections and two immunostained sections (for S-100 and HMB45) routinely on SLNs from melanoma patients.

The aim of the present study was to determine whether micromorphometric features of positive sentinel lymph nodes (SLNs) from patients with melanoma are useful for predicting further nodal involvement in completion lymph node dissection (CLND) specimens. Of 986 patients with melanoma undergoing SLN biopsy between March 1992 and February 2001, 175 (17.7%) had at least 1 positive SLN and 140 had subsequent CLND specimens available for review. Further nodal involvement in CLND specimens was present in 24 (17.1%) of 140 patients. Of 8 micromorphometric features of the SLNs that were assessed, the presence of metastases in CLND specimens was correlated significantly with a tumor penetrative depth (maximum distance of melanoma cells from the inner margin of the SLN capsule) of more than 2 mm (P < .05), a deposit size of more than 10 mm2 (P < .01), the presence of melanoma cells in perinodal lymphatic vessels (P < .01), and the effacement of nodal architecture by metastatic melanoma cells (P < .05). Our results indicate that some morphologic features of melanoma metastases in SLNs predict the likelihood of further nodal involvement in CLND specimens.

To determine morphologic features of melanophages under in vivo reflectance confocal microscopy (RCM) and to highlight morphologic features that are important in distinguishing melanophages from melanocytes.

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. Malignant melanomas had a significantly greater AgNOR number per nucleus, mean AgNOR area per nucleus, and variation in AgNOR area per nucleus compared with all types of benign nevi (p < 0.05). In multivariate discriminant analysis using a combination of four AgNOR counts and morphometric parameters, all CN and DN, 8 of 10 SN, and 23 of 24 MMs could be correctly classified as benign or malignant. The results suggest that both AgNOR count and morphology help to separate benign and malignant melanocytic lesions and that the combination of both sets of parameters improves their discriminating ability.