Sentinel lymph node
biopsy in histologically ambiguous melanocytic tumors with spitzoid
features (so-called atypical spitzoid tumors).Ann
Surg Oncol. 2008 Jan;15 (1):302-9. Epub
2007 Nov 14.
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.
Differentiating spitzoid melanomas from Spitz nevi through CD99
expression.J
Cutan Pathol. 2007 Jul;34(7):576-80.
BACKGROUND: A
true diagnostic marker differentiating Spitz nevi (SN) from
spitzoid melanoma (sMM) has been elusive. CD99, a transmembrane
glycoprotein, believed to play a role in many neoplastic
processes, has yet to be investigated in this regard. Recently,
the expression of CD99 has been shown in 60% of primary melanomas.
Other studies exploring the expression of CD99 in melanocytic
lesions have not been performed. Here, we evaluate the presence of
CD99 in these two histologically difficult to differentiate
entities. METHODS: Cases of sMM were selected based on the
presence of key microscopic words: spitz, spindled and/or
epitheliod. In addition, all the cases of SN over the past 7 years
were retrieved. Each case was stained with anti-human CD99 and
analyzed for the presence of CD99 staining. RESULTS: Fifteen of 27
cases (56%) of sMM expressed CD99 compared with only 3 of 58 cases
(5%) of SN. CONCLUSIONS: This study shows 56% of sMM and only 5%
of SN express CD99. Eight of the sMM showed strong diffuse
staining, a pattern not seen in any of the SN. This study does not
elucidate the role that CD99 plays in these melanocytic processes;
however, it does show that CD99 can be a useful tool in
distinguishing sMM from SN.