Pure desmoplastic melanoma: a melanoma with distinctive clinical behavior.
OBJECTIVE
The purpose of the study was to evaluate the excision margin necessary for desmoplastic melanoma (DM).


BACKGROUND
DM consists of 2 histologic subtypes, pure DM (PDM) and mixed DM (MDM), differing in extent of fibrotic component. We investigated clinical and therapeutic determinants of prognosis in these DM entities.


METHODS
We reviewed 118 PDM and 124 MDM treated at our Institute over 25 years. Local relapse, distant metastasis, and survival were studied.


RESULTS
Most (91.7%) distant metastases in PDM developed after 1 or more local recurrences; whereas distant metastasis usually (79.6%) occurred as first event in MDM. Overall mortality trends in relation to lesion-thickness-plus-excision-width differed for PDM (P = 0.014) but not MDM (P = 0.185). For PDM, 5-year crude cumulative incidence (CCI) of mortality was higher (40.0%) for thin tumors (≤ 2 mm thick) excised with 1 cm margin than those excised with 2 cm (14.8%); CCI of mortality for PDM > 2 mm thick excised with 2 cm margins (13.4%) was similar to that for thin PDM lesions excised with 2 cm (14.8%). CCI of local recurrence was also greater in PDM excised with 1 cm margins. In MDM, mortality increased with stage but was independent of excision width (CCI: 29.4% for ≤ 2 mm/2 cm, 31.3% for ≤ 2 mm/1 cm, and 48.3% for > 2 mm/2 cm); a similar trend was found for MDM distant metastases.


CONCLUSIONS
In PDM, limited excision width is associated with significantly greater local recurrence and mortality; treatment should be excision with 2 cm margins even for thin lesions. MDM behaves similarly to other melanomas; treatment should follow guidelines on melanoma management.
Departments of Surgery and Biometry, Fonda-zione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. andrea.maurichi@istitutotumori.mi.it
Andrea
A
Maurichi
Rosalba
R
Miceli
Tiziana
T
Camerini
Paolo
P
Contiero
Roberto
R
Patuzzo
Gabrina
G
Tragni
Federica
F
Crippa
Konstantinos
K
Romanidis
Roberta
R
Ruggeri
Antonino
A
Carbone
Mario
M
Santinami
D000368:Aged; D005260:Female; D005355:Fibrosis; D006801:Humans; D008297:Male; D008545:Melanoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D016019:Survival Analysis