Sentinel lymph node biopsy for patients with problematic spitzoid melanocytic lesions

Abstract

A new device—the rotational particle separator (RPS)—is compared to the cyclone for the removal of ultrafine particles, such as cryogenically condensed contaminant droplets from natural gas. The comparison focusses on identifying for each configuration the smallest size of particle which has a 50% chance of being removed from the gas stream. Whereas a cyclone can only separate 1 μm droplets at very low‐throughputs on the order of 1 MMscfd, at the same energy consumption and device volume, the rotational particle separator removes droplets of that size at throughputs of 300 MMscfd. The advantage of the rotational particle separator, therefore, lies in its compact separation potential for full‐scale industrial gas well throughputs. © 2006 American Institute of Chemical Engineers AIChE J, 2007

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“…We pointed out that this subgroup of tumors has a much more favorable prognosis than ''conventional'' melanomas and that the well-known, important prognosticators for conventional melanomas, such as tumor thickness and sentinel lymph node tumor-harboring status, do not appear to have the same significance for them. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] These facts support our proposal that such melanocytic tumors are biologically distinct and should be classified in a nosologic category separate from both melanomas and nevi.…”

The Spitzoid lesion: rethinking Spitz tumors, atypical variants, ‘Spitzoid melanoma' and risk assessment

“…Almost all completion lymphadenectomies for atypical Spitz tumors with positive SLNs have failed to show any residual tumor. 52,53 In addition, the latter patients have had no further disease recurrence with continued follow-up of 2-3 years. 53 Atypical Spitz tumor deposits in SLNs may possibly have a different biology or significance than metastases from conventional melanoma.…”

“…[51][52][53] Atypical Spitz-like tumors may have metastatic deposits in the peripheral sinuses or parenchyma of SLNs. 51 Although in general the finding of tumor deposits in SLN is de facto evidence for melanoma, only the study of sufficient numbers of cases with long-term follow-up will provide the data to know the biological significance of such SLN deposits associated with atypical Spitz tumors, if they are inherently different from conventional melanomas, and if they potentially have better prognoses.…”

BRAF and NRAS mutations in spitzoid melanocytic lesions

“…These criteria included expansile or sheet-like dermal growth, incomplete to absent dermal maturation, bulbous extension into the deep dermis or subcutis, deep dermal mitoses, and/or high-grade nuclear atypia. 10,13,16,21,22,48 Although the 13 spitzoid melanomas maintained some low-power resemblance to Spitz nevi, they demonstrated at least one, and often multiple, of the following histologic features: asymmetrical growth, lack of lateral circumscription, pagetoid spread of melanocytes in the epidermis, aberrant dermal growth, dermal mitoses at all levels of the lesion, atypical mitoses, and high-grade nuclear atypia. 9,10,12,13,48 The Institutional Review Board at the University of Michigan has approved this study.…”

“…These atypical spitzoid lesions have been referred to variously in the literature as borderline and intermediate melanocytic neoplasia, minimal-deviation melanoma, nevoid melanoma, atypical Spitz nevus/tumor, malignant Spitz nevus, problematic Spitzoid melanocytic lesions, and diagnostically controversial Spitzoid melanocytic tumors. [16][17][18][19][20][21][22] Recently, interest in the RAS-RAF-MEK-ERK-MAP kinase signal transduction pathway has arisen as a site for mutational analysis in a broad spectrum of melanocytic lesions, including Spitz nevi. In a landmark study by Davies et al, 23 66% of malignant melanomas were shown to harbor a T1796A BRAF mutation in exon 15 resulting in the substitution of valine by glutamic acid at position 600 (V600E).…”