Clinical implications of distinct metastasizing preferences of different melanoma subtypes.
BACKGROUND
The incidence and mortality of malignant melanoma have been rising during the past decades, the latter being due to the high invasion capacity and the metastatic potential of melanoma cells to distant organs.


OBJECTIVE
We investigated the distribution pattern of melanoma metastases taking into account different clinicopathological subtypes of melanoma.


METHODS
We studied 310 stage IV (AJCC 2009) melanoma patients retrospectively with regard to potential correlations between frequency and occurrence of metastasis and the genetic background and pathological/clinical melanoma subtypes. For all patients, the time to distant metastasis (TTDM) and the distribution patterns of metastases were analyzed and correlated to the median survival time.


RESULTS
Superficially Spreading (SSM) and Nodular melanomas (NMM) spread to the brain more frequently than Acrolentiginous (ALM) and Mucosal (MM) melanomas (p = 0.0012). The preference to affect the skeleton was significantly higher for ALM and MM in comparison to SSM and NMM (p = 0.0049). Lentigo maligna (LMM) tumors showed a significantly lower metastatic spread to distant lymph nodes (p = 0.0159). BRAF mutant versus wildtype tumors showed no significant differences concerning localization of metastasis but patients with BRAF mutant tumors were significantly younger at primary diagnosis and had a significantly shorter stage IV survival (p = 0.0106).


CONCLUSIONS
This study shows a clear distinction of melanoma subtypes with regard to metastasizing preferences. Further knowledge about melanoma subtype specific characteristics, including molecular markers predictive of homing preferences, may help to understand and manage this heterogeneous disease in terms of prognosis and follow-up procedures.
Department of Dermatology, University Hospital of Zurich, Gloriastr. 31, 8091 Zurich, Switzerland.
Nicola L
NL
Schoenewolf
Department of Dermatology, University Hospital of Zurich, Gloriastr. 31, 8091 Zurich, Switzerland.
Benedetta
B
Belloni
SAKK Coordinating Center, Effingerstr. 40, 3008 Bern, Switzerland;
Mathew
M
Simcock
Department of Dermatology, University Hospital of Zurich, Gloriastr. 31, 8091 Zurich, Switzerland.
Sabina
S
Tonolla
Department of Dermatology, University Hospital of Zurich, Gloriastr. 31, 8091 Zurich, Switzerland.
Pascale
P
Vogt
Department of Dermatology, University Hospital of Zurich, Gloriastr. 31, 8091 Zurich, Switzerland.
Ellen
E
Scherrer
Department of Otorhinolaryngology, University Hospital of Zurich, Frauenklinikstr. 24, 8091 Zurich, Switzerland.
David
D
Holzmann
Department of Dermatology, University Hospital of Zurich, Gloriastr. 31, 8091 Zurich, Switzerland.
Reinhard
R
Dummer
D000328:Adult; D006801:Humans; D008545:Melanoma / Q000145:classification* / Q000556:secondary*; D009367:Neoplasm Staging; D012189:Retrospective Studies; D012878:Skin Neoplasms; D000096142:Cutaneous Malignant Melanoma
melanoma metastasis; melanoma subtypes; predictive metastatic patterns; prognostic factors