Histological characteristics of metastasizing thin melanomas: a case-control study of 43 cases.
OBJECTIVE
To study clinical and histological features associated with metastasizing thin melanomas (MTMs).


METHODS
Case-control study of clinicopathological features of patients with MTMs by a panel of 10 dermatopathologists.


METHODS
Members of the North American Melanoma Pathology Study Group selected the cases from the melanoma databases at 8 academic institutions.


METHODS
Forty-three patients with MTMs (<1 mm thick) and 42 control subjects without metastasis matched for age, sex, tumor site, and Breslow thickness.


METHODS
None.


METHODS
Clinical (age, sex, site of lesion, stage at diagnosis, metastasis site, disease-free survival, and outcome) and histological (Breslow thickness, Clark level, growth phase, regression, and inflammatory response) features of patients with MTMs vs controls.


RESULTS
There was an overrepresentation of axial tumors among patients with MTMs. Extensive regression was present in 18 patients (42%) with MTM vs 2 matched control subjects (5%) (95% confidence interval, 21%-53%; P =.001). Other histological variables were not significantly different. Two patients had melanomas in situ with subsequent metastasis.


CONCLUSIONS
Thin melanomas with extensive regression represent a group at higher risk for the development of metastasis. Furthermore, the risk of metastasis cannot be dismissed in cases of melanoma in situ.
Guitart
Joan
J
Department of Dermatology, Northwestern University Medical School, 675 N St Clair, Suite 19-150, Chicago, IL 60611, USA. j-guitart@nwu.edu
Lowe
Lori
L
Piepkorn
Michael
M
Prieto
Victor G
VG
Rabkin
Michael S
MS
Ronan
Salve G
SG
Shea
Christopher R
CR
Tron
Victor A
VA
White
Wain
W
Barnhill
Raymond L
RL
D000328:Adult; D000368:Aged; D002278:Carcinoma in Situ / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology*; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D012075:Remission, Spontaneous; D012307:Risk Factors; D012878:Skin Neoplasms / Q000473:pathology*