Melanoma of unknown primary site: a 33-year experience at the Turin Melanoma Centre

Abstract

This is an author version of the contribution published on:Questa è la versione dell'autore dell'opera: AbstractUnknown melanoma occurs as metastasis to skin, nodes or viscera, without a detectable cutaneous primary tumour. We reviewed our database of 4881 melanoma patients, diagnosed and followed up prospectively for a 33-year period. We identified 93 cases of metastatic melanoma without evidence of primary; however, five of these patients had a history of a previous excision of a presumed benign lesion without histological examination and were excluded from analyses. At diagnosis, metastases were cutaneous in 35.3% of cases, nodal in 43.2% and visceral in 17% of cases; in 4.5% of patients, both skin and nodes were involved. In all cases, clinical inspection and staging procedures performed at diagnosis of metastatic disease failed to identify a primary melanoma. In 11 cases (11.8%), extensively regressed pigmented lesions (without evidence of melanoma cells at the histological examination) were documented; moreover, we identified in our series five patients with unknown primary affected by vitiligo. The 5-year and 10-year overall survival rates were 49.6 and 41.4%, respectively, with a median of 4.9 years. The 5-year and 10-year time to progression rates were 39.4 and 32.3%, respectively, with a median of 2.3 years. Survival was longer in females and showed significant differences among patients with skin, lymph node or visceral involvement at diagnosis. In melanoma patients, unknown primary represents a not so rare event, with an uncertain origin. We confirmed the relatively good prognosis of unknown primary melanoma patients, a fact that has to be taken into consideration for their management.

Results of systemic treatment of cutaneous melanoma in inoperable stage III and IV

“…A similar correlation occurred between patients with metastasis from an unknown primary site and patients with established diagnosis of cutaneous melanoma. The fact is confirmed by other studies regarding outcomes of melanomas from an unknown primary site [36–39]. Another important factor is patient general status according to ZUBROD/ECOG/WHO scales at the time of therapy initiation.…”

Treatment of melanoma of unknown primary in the era of immunotherapy and targeted therapy: A Dutch population‐based study

“…This stage migration might be explained by the increased use of whole‐body positron emission tomography, which in turn, might have increased the early detection of visceral metastases. In contrast to this result, previous studies have shown that patients with MUP tend to present with nodal involvement alone and less often with visceral metastasis . This inconsistency may be explained by issues with the earlier studies, which used small sample sizes (65–88 patients) and data from single specialist centres for melanoma care.…”

Stage IV malignant melanoma of unknown primary site in a young man

“…Current literature has shown that the MUP concerns ∼2–9% of all melanoma cases 1. Savoia et al ,5 in a series of 93 MUP patients, report that the lymph node involvement as the first manifestation of the disease occurred in half of the examined cases. The theories concerning the aetiology of MUP are: (1) spontaneous regression of the primary lesion, (2) unidentified primary melanoma, (3) previous excision of what was initially considered a benign lesion and (4) a primary origin of melanoma in lymph nodes 5–7.…”