SLNB histology in melanomas < or = 1.0 mm deep is a significant predictor of outcome. SLNB should be considered for selected patients with melanomas .75 to 1.0 mm.
Objective
Selective focal MR‐Signal (diffusion‐) changes in the CA‐1 sector of the hippocampus have been described in transient global amnesia (TGA), but the pathophysiological substrate of these lesions is largely unknown. As several imaging and epidemiological findings point to a vascular origin an analysis of the temporal evolution of the hippocampal apparent diffusion coefficient (ADC) changes may offer new understanding of the pathomechanisms of TGA.
Methods
The time course of the ADC of hippocampal DWI lesions in TGA patients was studied using serial 3 T high‐resolution MR‐imaging within 1‐10 days as well as 4‐6 months after TGA. ADC values from 76 MR‐studies were analyzed and expressed as ratio ADC (rADC) in reference to the unaffected hemisphere.
Results
Twenty‐nine patients with TGA showed 34 DWI lesions with corresponding T2 lesions in the CA‐1 sector of the hippocampal cornu ammonis within a time window of 24‐72 h after onset. Ratio ADC decreased below 1.0 (0.66 ± 0.08) 24 h after the acute TGA episode and did show a further significant decrease to 0.57 ± 0.1 after 3 days (p < 0.05). After 72 h, rADC increased and normalized around day 10 with rADC values of 1.0 (p < 0.05).
Interpretation
The temporal evolution of the rADC in hippocampal signal changes in TGA shows a time course previously described for ischemic lesions in human stroke patients. This might imply a vascular origin of diffusion changes leading to a transient perturbation of memory relevant circuits in the hippocampus. Ann Neurol 2007
FDG-PET reliably detects lymph node tumor deposits greater than approximately 80 mm(3) volume, but sensitivity falls rapidly below this. This amount of tumor is most likely to occur in patients with AJCC stage III or IV disease.
The histologic status of the sentinel lymph node is a highly significant prognostic factor for patients with clinically localized cutaneous melanoma. The patterns of initial treatment failure of patients with positive sentinel lymph node biopsy versus those with negative results have not been well described. The purpose of this study was to determine the relative prognostic importance of sentinel lymph node status and to compare patterns of initial treatment failure and prognosis of node-positive versus node-negative cutaneous melanoma patients staged by sentinel lymph node biopsy and selective lymphadenectomy. The authors reviewed the pertinent demographic and surgical data in a consecutive series of patients with cutaneous melanoma who underwent sentinel lymph node staging of nonpalpable regional nodes. Sentinel lymph node biopsy was performed using a combination of blue dye and radiolocalization. Patients with positive biopsy results underwent selective lymphadenectomy, whereas those with negative results were observed. Site(s) and date(s) of initial recurrence and death were determined, and disease-free and overall survival probabilities were compared between positive and negative groups using the log-rank test and multivariable Cox regression analysis. Between February of 1994 and August of 2000, 408 patients with melanoma underwent sentinel lymph node biopsy to stage 518 regional lymph node basins. Mean Breslow tumor thickness was 2.27 mm (range, 0.2 to 14.0 mm). Eighty-five patients (20.8 percent) had at least one histologically positive sentinel lymph node, and selective lymphadenectomy yielded additional positive lymph nodes in 18 of 84 patients (21.4 percent). Recurrences were noted in 70 patients (17 percent) at a median follow-up period of 31.4 months. Recurrences were more frequent in patients with positive biopsy results (36.5 percent) than in those with negative results (12.1 percent, p < 0.0001). Distant sites of initial recurrence were more likely in the positive group than in the negative group (71 percent versus 49 percent of recurrences, respectively; p = 0.06). The false-negative rate for sentinel lymph node staging was 4.5 percent and overall accuracy was 99 percent compared with clinical follow-up. Disease-free and overall survival correlated significantly with tumor thickness, ulceration, sentinel lymph node status, and the number of tumor-positive lymph nodes (two-sided p < 0.0001 for all comparisons). Multivariable analysis revealed that sentinel lymph node status (p = 0.003), tumor thickness (p = 0.016), ulceration (p = 0.006), and age (p = 0.003) were significant independent predictors of survival for the entire group. Tumor thickness and ulceration were significant predictors of recurrence and survival in sentinel node-negative patients but not in sentinel node-positive patients. Sentinel lymph node histology is possibly the most important negative predictor of early recurrence and survival in patients with American Joint Committee on Cancer stage I and II melanoma. The number of posi...
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