Clinical Aspects of Unknown Primary Melanoma

Abstract

Of 980 patients with malignant melanoma treated during the past seven years, 55 (5.6%) were found to have metastatic disease and no detectable primary tumor. Thirty-six of these patients with "unknown primary melanoma" had disease limited to lymph nodes (Stage II), whereas 19 had disseminated melanoma (Stage III). The sex and age distribution of these 55 patients were similar to those of a control group of 86 patients with palpable lymph node metastases from a known primary. The site of lymph node metastases for Stage II patients in each group was similar although unknown primary patients seemed to have slightly more involved lymph nodes. By studying patients with the same stage and similar extent of disease, the prognosis of unknown primary melanoma could be determined and compared to known primary melanoma. The overall recurrence rate of patients with unknown primary was no higher than that of patients with known primary. This observation appeared to be true even when patients were compared with respect to adjuvant immunotherapy. The use of adjuvant immunotherapy appeared to favorably affect recurrence rates among the unknown primary patients. Since the recurrence rate for patients with unknown primary melanoma was no higher than that of patients with known primary melanoma, we advocate aggressive surgical management. The occasional long-term survivor with Stage III unknown primary suggests that judicious surgical intervention may benefit these patients as well.

Lung metastasis of malignant melanoma with unknown primary origin

“…Malignant melanoma cases with unknown primary origin are rarely seen, constituting 2-6% of all malignant melanoma cases (3)(4)(5). In the study conducted by de Waal et al (4), the primary origin was reported to be unknown in 857 (2.6%) of 33,181 melanoma patients monitored between 2003 and 2009.…”

Pleomorphic adenoma of the upper lip

“…Several studies have reported worse prognosis for patients with MUPs (10), while others have reported better (2,6,11) or similar survival rates (3,7). With regard to isolated subcutaneous masses, Schlagenhauff et al reported a 5 year survival of 83% (2).…”

“…This problem becomes even more complex when it presents as a metastatic lesion with no known primary site. Melanomas of unknown primary site account for 1-8% of all melanomas in different series (1)(2)(3)(4)(5)(6)(7). Lymph node metastases account for nearly two third of these cases in most of the series with axillary lymph nodes being the most common site.…”

Melanoma of Unknown Primary as a Cause of Intestinal Obstruction - a Case Description

“…Unfortunately, in spite of precise diagnostics it is impossible to locate the primary site of the tumour. Melanoma of unknown primary applies to 1-8% of all diagnosed melanomas (1,2,3). It is usually diagnosed when patients can observe clinical symptoms in the form of metastases.…”

“…In order to make a definite diagnosis of melanoma of unknown primary it is necessary to confirm the presence of metastases histopathologically and to exclude all possible locations of the primary focus. There are several theories attempting to explain the aetiology of melanoma of unknown primary (2,3). The first is a spontaneous regression of the primary focus as an effect of the immune system and the other is a malignant transformation of individual melanocytes, which enter a lymph node without forming a focus within any organ (2,3).…”