Dermal melanoma: A report on prognosis, outcomes, and the utility of sentinel lymph node biopsy

Abstract

Introduction Historically dermal melanoma (DM) has been labeled as either stage IIIB (in-transit) or stage IV (M1a) disease. We sought to investigate the natural history of DM and the utility and prognostic significance of sentinel lymph node biopsy (SLNB). Methods Patients with DM undergoing SLNB at a single center from 1998 to 2009 were identified. Results Eighty-three patients met criteria, 10 (12%) patients had a positive SLNB. Of those, 5 (50%) recurred (all with distant disease). Twenty-one (29%) of the 73 SLNB negative patients recurred and of those, 15 (71%) developed distant metastases, whereas 6 (29%) developed local or regional recurrence, including two false-negative regional nodal recurrences. No in-transit recurrences were recorded. Five-year recurrence-free and disease-specific survival was significantly better for patients with a negative SLNB versus positive SLNB (56.8% vs. 22.2% P =0.02, 81.1% vs. 61.0%, P =0.05, respectively). Conclusion SLNB has prognostic significance for RFS and DSS, and should be utilized in the management of DM based on a >10% yield and low false-negative rate. Our data demonstrate patients with DM do not recur in an in-transit fashion, which along with the survival outcomes suggest the behavior of DM is consistent with primary cutaneous melanoma of similar thickness rather than an isolated in-transit or distant dermal metastasis from a regressed cutaneous primary.

Primary Dermal Melanoma: A Rare Clinicopathological Variant Mimicking Metastatic Melanoma

“…The cases of putative PDM reported in the literature represent a heterogeneous and controversial group of melanomas, including primary nodular melanoma with an occult intraepidermal component, metastatic melanoma with an initial occult primary origin, melanoma arising within and obliterating a pre-existing melanocytic nevus, and a group of true PDM [ 13 , 14 , 15 ].…”

“…Moreover, most conventional staging parameters normally used for prognosis in CM have limited applicability to PDM. Breslow depth and ulceration have no statistically significant relationship with recurrence compared to conventional melanomas [ 3 , 4 , 15 ]. Additional research focusing on appropriate staging and outcome is necessary to delineate this largely indefinite melanoma variant better.…”

Clinical significance of tumor mitotic rate and lack of epidermal attachment in melanoma of the head and neck

“…12,13 These tumors may be a unique subtype of melanoma, distinct from dermal metastases. 11,14 Although histologically similar to metastatic disease, this distinct subtype of melanoma has unexpectedly high survival, which would not be expected from metastatic melanoma of unknown primary. 15 Metastatic melanoma to distant skin, subcutaneous, and nodal sites has an estimated 5-year survival of 5%-19% compared to 80%-100% in primary dermal melanoma.…”

“…Primary dermal melanoma is thought to represent about 0.4%‐0.9% of all melanomas . These tumors may be a unique subtype of melanoma, distinct from dermal metastases . Although histologically similar to metastatic disease, this distinct subtype of melanoma has unexpectedly high survival, which would not be expected from metastatic melanoma of unknown primary .…”

“…Primary dermal melanomas are defined as melanomas situated in the dermis and/or subcutaneous fat with lack of epidermal attachment and no evidence or history of a primary cutaneous melanoma . In this study, primary dermal melanoma is defined as a melanoma (collection of atypical melanocytes that are pleomorphic, often mitotically active) within the dermis without overlying melanoma in situ from which it is arising, in the absence of evidence that this is a metastasis from another primary melanoma.…”