Garble That Derives From Lack of Definition

Histologically ambiguous ("borderline") primary cutaneous melanocytic tumors: approaches to patient management including the roles of molecular testing and sentinel lymph node biopsy

It is well recognized that the pathologic diagnosis of melanocytic tumors can sometimes be difficult. For some atypical melanocytic tumors that do not display clear-cut features of malignancy, it may be difficult or impossible to exclude a diagnosis of melanoma; this includes those showing some resemblance to Spitz nevi, blue nevi, deep penetrating nevi, and possible nevoid melanomas. When there is uncertainty about whether a primary melanocytic tumor is a nevus or a melanoma, we recommend that a second opinion be sought from one or more experienced colleagues. If diagnostic uncertainty persists, the evidence for or against the various differential diagnostic considerations should be presented in the pathology report and a "most likely" or "favored" diagnosis given. Molecular testing of the primary tumor by using techniques such as comparative genomic hybridization or fluorescence in situ hybridization may assist in establishing a diagnosis of melanoma if multiple chromosomal aberrations are identified. However, these tests require further independent validation and are not widely available at present. Complete excision of the lesion is probably mandatory, but plans for further management should be formulated on a case-by-case basis. While the safest course of action will usually be to manage the tumor as if it were a melanoma (taking into account the tumor's thickness and other prognostic variables), this may not always be appropriate, particularly if it is located in a cosmetically sensitive site such as the face. In some cases, it may be appropriate for the surgical oncologist to convey the diagnostic uncertainty to patients and to present them with management choices so that they can decide whether they wish to be managed aggressively (as for a melanoma) or conservatively. While a sentinel lymph node biopsy may be recommended on the basis of the primary tumor characteristics, the clinical significance of lymph node involvement for these tumors is not yet clear, and it may not have the same prognostic implications as nodal involvement from an unequivocal "conventional" melanoma.

Sentinel lymph node biopsy for patients with diagnostically controversial Spitzoid melanocytic tumors?

The distinction of a Spitz nevus from melanoma can be very difficult. Pathologists may disagree on whether a Spitzoid melanocytic proliferation is benign or malignant, or acknowledge uncertainty about the diagnosis. As long as melanoma is suspected or strongly considered, a clinical management plan is often adopted as if the patient had melanoma, which may include sentinel lymph node (SLN) biopsy for staging. The findings of the sentinel node may resolve the diagnostic controversy about the primary tumor, but there is also the risk for more diagnostic confusion, uncertainty, and errors. We review the arguments in favor and against SLN biopsy for patients with diagnostically controversial Spitzoid melanocytic tumors, summarize current experience, and illustrate diagnostic pitfalls. Although SLN biopsy provides prognostic information helpful for clinical trials, we caution against performing the procedure as a diagnostic adjunct.

Sentinel lymph node biopsy in histologically ambiguous melanocytic tumors with spitzoid features (so-called atypical spitzoid tumors)

BACKGROUND

The distinction of Spitz nevi from melanomas with spitzoid morphology can be difficult. For lesions with overlapping histopathologic features, it may be impossible to predict their malignant potential with certainty. The current study evaluated the role of sentinel lymph node (SLN) biopsy in patients with such atypical spitzoid tumors.

METHODS

The clinical and histopathologic features of 21 patients with atypical spitzoid tumors who underwent SLN biopsy were reviewed and correlated with the presence or absence of metastatic tumor in their corresponding SLNs.

RESULTS

The atypical histopathologic features that were most frequently present included incomplete maturation (11 patients, 52%), two or more dermal mitoses per square millimeter (13 patients, 62%), and deep dermal mitoses (11 patients, 52%). Six patients (29%) showed SLN metastasis. There were histopathologic differences between tumors with positive SLN when compared with tumors with negative SLN: mean tumor thickness (3.38 mm vs. 2.04 mm), incomplete maturation (83% vs. 40%), median dermal mitotic rate (3.5/mm(2) vs. 2/mm(2)), deep dermal mitoses (83% vs. 47%), and expansile dermal nodules (50% vs. 13%). However, of these, only the difference in mean tumor thickness reached statistical significance (P < .05).

CONCLUSIONS

SLN biopsy offers a means of assessing the metastatic potential of atypical spitzoid tumors and aids in the management of these patients by selecting patients who may benefit from a regional node field dissection and those in whom the use of adjuvant therapies could be considered.