The role of lymphatic mapping and sentinel node biopsy in the management of atypical and anomalous melanocytic lesions.
ABSTRACT Atypical and anomalous melanocytic lesions are tumors that cannot be determined by microscopy to be certainly benign or fully malignant. The malignant potential of these borderline lesions is unknown and logical determination of best therapy is challenging, in particular whether lymphatic mapping and sentinel node biopsy have a place in their management. Lesions that fall into this category include atypical Spitzoid lesions, atypical cellular blue nevi, combined nevi, deep penetrating nevi, ancient nevi, desmoplastic nevi, balloon cell nevi and proliferation nodules of congenital nevi. We report our experience managing patients with these problematic tumors and discuss our approaches to determining the true location of lesional cells in sentinel nodes.
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ABSTRACT: Combined melanocytic nevi are composed of 2 or more distinct populations of nevomelanocytes. Most commonly used to describe the combination of blue nevi with common nevi, it may also be applied to other combinations of benign melanocytic proliferations, including Spitz nevi and nevi with deep dermal pigmented nevomelanocytes. We report the incidence and distribution of these tumors at the Massachusetts General Hospital over the past decade and review guidelines for diagnostic criteria and nomenclature. Between 2000 and 2010 we identified 511 cases of combined nevi, represented by 4 histologically distinct diagnostic categories: (1) blue nevus, (2) nevi with deep dermal pigmented nevomelanocytes (plexiform/deep penetrating, inverted type A/clonal), (3) Spitz or pigmented spindled cell nevus, combined with another type of nevus (usually common or dysplastic), and (4) other combinations including 2 or more nevus types. Nearly one fifth of these tumors displayed atypical features; atypia was observed more often in combined nevi with Spitz or deep pigmented elements (26 of 55, 47%, and 25 of 98, 26%, respectively) than in combined common and blue nevi (37 of 336, 11%). Clinical follow-up data were available for 83% of the patients with atypical combined nevi; none developed recurrence or metastasis with a mean follow-up of over 4 years.The American journal of surgical pathology 08/2011; 35(10):1540-8. · 4.06 Impact Factor
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ABSTRACT: A subset of difficult melanocytic lesions exists with histopathologic features that evade diagnostic consensus from even expert dermatopathologists. Comparative genomic hybridization (CGH) has emerged as a useful diagnostic tool to categorize these lesions, by identifying known chromosomal aberrations in malignant melanoma or the lack thereof in melanocytic nevi. However, determining a lesion's biological behavior primarily on CGH is limited by a relatively small series of corroborative cases without long term follow up. We present a case of a pigmented lesion on the right cheek of a 4 year old boy. The lesion had features of a deep penetrating nevus, but the presence of frequent mitoses, tumor infiltrating lymphocytes, and microscopic foci of tumor necrosis were concerning for an unusual melanoma. We termed this lesion a melanocytic tumor of uncertain potential (MELTUMP) for these reasons. High-resolution array-CGH performed elsewhere on the lesion demonstrated no melanoma-associated genomic abnormalities. A sentinel lymph node biopsy of this patient later revealed multiple small tumor deposits. Although the presence of nodal involvement in similar lesions often do not lead to progressive and fatal disease, this case illustrates that atypical melanocytic lesions with nodal involvement may not demonstrate genomic abnormalities by CGH, and that histopathologic assessment remains paramount in defining these difficult melanocytic lesions. Further comprehensive study of these lesions is needed.Journal of Cutaneous Pathology 01/2012; 39(1):21-4. · 1.77 Impact Factor
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ABSTRACT: Applications that require the use of softball-sized or smaller robots impose size and power constraints that prohibit the use of active sensors such as ladar or sonar for mapping and localization. The small size of such robots also makes passive stereo vision impractical due to the limited baseline. As a result, map building capabilities for such robots will need to be based on structure from motion using monocular sequences of images. This paper presents a novel algorithm for estimation of 2-D hallway structure and robot motion given a set of feature observations from multiple images. The 2-D structure from motion algorithm is posed in a way that is linear in Cartesian coordinates given a set of camera rotations. Given an observation of a feature from a camera position, for a specified rotation of the camera's coordinate system relative to the world there is a linear constraint that the camera's location and the feature's location should both lie along the line of sight between the camera and the feature. Starting with an initial set of camera orientations, the algorithm iteratively switches between refining the estimated camera and feature positions and refining the estimated camera rotations. The performance of the structure from motion algorithm is demonstrated by comparison of the algorithm results on a sequence of images to the manually measured true structure of a typical hallway.Intelligent Vehicles Symposium, 2003. Proceedings. IEEE; 07/2003