Abstract
(1) Background: The purpose of this retrospective study was to evaluate the recurrence and survival rates of metastatic melanoma of unknown primary origin (MUP), in order to further refine current recommendations for the surgical treatment; (2) Methods: Medical data of all MUP patients registered between 2000 and 2011, were analyzed. Seventy-eight patients were categorized in either lymph node (axilla, groin, head-and neck) or subcutaneous MUP. Axillary node MUPs were generally treated with dissections of levels I-III, inguinal node MUPs with combined superficial and deep groin dissections, and head-and-neck node MUPs with neck dissections to various extents, based on lymph drainage patterns. Subcutaneous lesions were excised with 1–2 cm margins. The primary outcome was treatment outcomes in terms of (loco)regional recurrence and survival rates; (3) Results: Lymph node MUP recurred regionally in 11% of patients, with an overall recurrence rate of 45%. In contrast, subcutaneous MUP recurred locally in 65% of patients with an overall recurrence rate of 78%. This latter group had a significantly shorter disease-free interval than patients with lymph node MUP (p = 0.000). In the entire study population, 5-year and 10-year overall survival rates were 56% and 47% respectively, with no differences observed between the various subgroups; (4) Conclusion: The relatively low regional recurrence rate after regional lymph node dissection (11%) supports its current status as standard surgical treatment for lymph node MUP. Subcutaneous MUP, on the contrary, appears to recur both locally (65%) and overall (78%) at a significantly higher rate, suggesting a different biological behavior. However, wide local excision remains the best available option for this specific group.
Highlights
In approximately 3% of all melanoma cases, patients present metastatic melanoma in either lymph nodes,cutaneous tissue, or visceral sites, without a detectable primary tumor, despite extensive examinations [1]
Between January 2000 and December 2011, 3491 patients with melanoma were treated in our institute, of whom 155 (4%) were registered with melanoma of unknown primary origin (MUP)
Twenty patients appeared to have proven or suspected primary melanomas; 52 already had visceral metastases at first presentation; one patient had a metastatic lesion in an unusual basin; three patients lacked sufficient data to confirm the diagnosis of MUP; and one patient on immunohistochemical evaluation had turned out to have a sarcoma
Summary
In approximately 3% of all melanoma cases, patients present metastatic melanoma in either lymph nodes, (sub)cutaneous tissue, or visceral sites, without a detectable primary tumor, despite extensive examinations [1]. There may have been a prior lesion at the site that at the time had been excised without proper histologic analysis, or ectopic nodal nevus cells may have turned malignant in regional lymph nodes [4,5]. The most common clinical presentation of metastatic melanoma of unknown primary origin (MUP). As the primary site is unknown, little can be said about the regional or distant nature of solitary lymph node metastases, but they commonly develop in axilla (54%), neck (26%), and groin (20%) [4,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
