Melanoma of unknown primary site: presentation, treatment, and prognosis--a single institution study. University of Pennsylvania Pigmented Lesion Study Group

A patient with rapidly growing axillary masses

ABSTRACT

About 85,000 melanomas are diagnosed every year in the United States, but only about 3.2% are diagnosed without a primary site. This article describes a patient who presented with two rapidly growing axillary masses and was found to have metastatic melanoma of the lymph nodes with no known primary site. Melanoma of unknown primary (MUP) site is staged either III or IV level. Management is determined in the same manner as stage-matched melanoma of known primary site.

Survival after lymphadenectomy of nodal metastases from melanoma of unknown primary site

Although the vast majority of melanomas have a primary site, 3%-4% of all melanomas in distant sites display no known primary site (MUP). This phenomenon is not fully understood and various hypotheses have been introduced. The prognostic significance of MUP has been unclear, with some studies showing no survival benefit while others find improved survival compared to stage-matched patients with melanoma of known primary site (MKP). Between 1997 and 2014, 864 patients underwent an en bloc resection of clinical nodal metastases at a referral centre for metastatic melanoma in Norway. The MUP (n = 113) and MKP (n = 751) patients were graded with stage III or IV. The overall survival (OS) was calculated with the Kaplan-Meier method, and multivariate analysis identified factors of significance for the two groups. A significant five-year OS emerged for stage III, MUP = 58% and 42% for MKP, but not for stage IV. The five-year relapse-free survival (RFS) was 41% and 31% for MUP and MKP respectively (p = 0.049). The statistically significant inter-group differences (MUP/MKP) were observed in the univariate and multivariate analyses of age, gender, number of affected nodes, tumour size and perinodal growth within stage III and tumour size within stage IV. After regional lymphadenectomy, MUP patients with clinical nodal metastases had a better outcome than MKP patients. This finding supports the theory that an endogenously mediated immune response may promote the regression of a cutaneous melanoma.

Phenotypic Switching of B16F10 Melanoma Cells as a Stress Adaptation Response to Fe3O4/Salicylic Acid Nanoparticle Therapy

Melanoma is a melanocyte-derived skin cancer that has a high heterogeneity due to its phenotypic plasticity, a trait that may explain its ability to survive in the case of physical or molecular aggression and to develop resistance to therapy. Therefore, the therapy modulation of phenotypic switching in combination with other treatment modalities could become a common approach in any future therapeutic strategy. In this paper, we used the syngeneic model of B16F10 melanoma implanted in C57BL/6 mice to evaluate the phenotypic changes in melanoma induced by therapy with iron oxide nanoparticles functionalized with salicylic acid (SaIONs). The results of this study showed that the oral administration of the SaIONs aqueous dispersion was followed by phenotypic switching to highly pigmented cells in B16F10 melanoma through a cytotoxicity-induced cell selection mechanism. The hyperpigmentation of melanoma cells by the intra- or extracellular accumulation of melanic pigment deposits was another consequence of the SaIONs therapy. Additional studies are needed to assess the reversibility of SaIONs-induced phenotypic switching and the impact of tumor hyperpigmentation on B16F10 melanoma’s progression and metastasis abilities.

A Solitary Melanoma Metastasis Confined to the Submandibular Gland

Malignant melanoma is a type of cancer that most commonly originates from the skin, less frequently from mucosal surfaces, the eye, or meninges [Annu Rev Pathol. 2014;9(1):239-71]. In 2019, this type of malignancy was the third most frequent cancer to be diagnosed in males and the fifth most in females according to the American Cancer Society and the National Cancer Institute [CA Cancer J Clin. 2019;69(5):363-85]. The majority of the malignant melanomas in the head and neck region (85-90%) are cutaneous lesions, most often arising in the skin of the face [Head Neck. 2016;38:147-155]. In sharp contrast are the histological findings of metastatic melanoma with an unknown primary site: they are much more scarce and histologically difficult to diagnose. The literature is limited to case studies or small cohorts. In 2-6% of all patients suffering from metastatic melanoma, after clinical examination of the skin and mucosa, imaging, and other diagnostic examination, a primary tumor cannot be found [Eur J Cancer. 2004;40(9):1454-5]. A very small subgroup (0.5%) presents with a single focus of melanoma within the dermis or subcutaneous tissues [Arch Dermatol. 2000;136(11):1397-9]. We hereby report a case in this subgroup of a solitary melanoma metastasis found in the submandibular gland in a 59-year-old male. The tumor was discovered incidentally after surgical excision of this gland because of nodular enlargement.

Clinical outcome of patients with metastatic melanoma of unknown primary in the era of novel therapy

Melanoma of unknown primary (MUP) is considered different from melanoma of known primary (MKP), and it is unclear whether these patients benefit equally from novel therapies. In the current study, characteristics and overall survival (OS) of patients with advanced and metastatic MUP and MKP were compared in the era of novel therapy. Patients were selected from the prospective nation-wide Dutch Melanoma Treatment Registry (DMTR). The following criteria were applied: diagnosis of stage IIIc unresectable or IV cutaneous MKP (cMKP) or MUP between July 2012 and July 2017 and treatment with immune checkpoint inhibition and/or targeted therapy. OS was estimated using the Kaplan–Meier method. The stratified multivariable Cox regression model was used for adjusted analysis. A total of 2706 patients were eligible including 2321 (85.8%) patients with cMKP and 385 (14.2%) with MUP. In comparative analysis, MUP patients more often presented with advanced and metastatic disease at primary diagnosis with poorer performance status, higher LDH, and central nervous system metastases. In crude analysis, median OS of cMKP or MUP patients was 12 months (interquartile range [IQR] 5 – 44) and 14 months (IQR 5 – not reached), respectively (P = 0.278). In adjusted analysis, OS in MUP patients was superior (hazard rate 0.70, 95% confidence interval 0.58–0.85; P < 0.001). As compared to patients with advanced and metastatic cMKP, MUP patients have superior survival in adjusted analysis, but usually present with poorer prognostic characteristics. In crude analysis, OS was comparable indicating that patients with MUP benefit at least equally from treatment with novel therapies.

Melanoma of Unknown Primary: Evaluation of the Characteristics, Treatment Strategies, Prognostic Factors in a Monocentric Retrospective Study

Background

Melanoma of unknown primary (MUP), accounts for up to 3% of all melanomas and consists of a histologically confirmed melanoma metastasis to either lymph nodes, (sub)cutaneous tissue, or visceral sites without any evidence of a primary cutaneous, ocular, or mucosal melanoma. This study aimed to investigate the characteristics, treatment strategies, and prognostic factors of MUP patients, in order to shed some light on the clinical behavior of this malignancy.

Methods

All the consecutive patients with a diagnosis of MUP referring to our institutions between 1985 and 2018 were considered in this retrospective cohort study. The records of 173 patients with a suspected diagnosis of MUP were retrospectively evaluated for inclusion in the study. Patient selection was performed according to the Das Gupta criteria, and a total of 127 MUP patients were finally included in the study, representing 2.7% of the patients diagnosed with melanoma skin cancer at our institutions during the same study period. A second cohort of all consecutive 417 MKP patients with AJCC stages IIIB–IV, referring tions in the period considered (1985–2018), was included in the study to compare survival between MUP and MKP patients. All the diagnoses were based on histopathologic, cytologic and immunohistochemical examination of the metastases. All tumors were re-staged according to the 2018 American Joint Committee on Cancer (AJCC) 8^th Edition.

Results

Median follow-up was 32 months (IQR: 15–84). 3-year progression-free survival (PFS) was 54%, while 3-year overall survival (OS) was 62%. Worse OS and PFS were associated with older age (P = 0.0001 for OS; P = 0.008 for PFS), stage IV (P < 0.0001 for OS; P = 0.0001 for PFS) and higher Charlson Comorbidity Index (P < 0.0001 for OS and P = 0.01 for PFS). Patients with lymph node disease showed longer PFS (P = 0.001) and OS (P = 0.0008) than those with (sub)cutis disease. Complete lymph node dissection (CLND) was the most common surgical treatment; a worse OS in these patients was associated with the number of positive lymph nodes (P = 0.01), without significant association with the number of retrieved lymph nodes (P = 0.79). Survival rates were lower in patients undergoing chemotherapy (CT) and target therapy (TT), and higher in those receiving immunotherapy (IT). 417 patients with AJCC stages IIIB–IV of Melanoma Known Primary (MKP) were included for the survival comparison with MUP. 3-year PFS rates were 54 and 58% in MUP and MKP, respectively (P = 0.30); 3-year OS rates were 62 and 70% in MUP and MKP, respectively (P = 0.40).

Conclusions

The most common clinical scenario of our series was a male patient around 59 years with lymph node disease. We report that CLND associated with IT was the best treatment in terms of survival outcome. In the current era of IT and TT for melanoma, new studies have to clarify the impact of novel drugs on MUP.

Metastatic malignant melanoma of unknown primary in temporalis muscle

Metastatic melanoma of unknown primary (MUP) is an uncommon melanocytic lesion found in distant sites with no evident skin involvement. This case report presents a 75-year-old woman who underwent local excision for a lump in the right temporal area, which had been present for 6 months and had been suspected to be a lipoma. Histology confirmed that the tissue excised from the temporalis muscle was composed of atypical, heavily pigmented melanocytes. Her history was negative for melanocytic lesions, and examination and extensive investigation including imaging had failed to identify a primary lesion. The patient is currently being followed up.

Melanoma Characteristics in Patients with a History of UV Tanning Bed Usage

OBJECTIVE

The purpose of this study was to evaluate the effect of tanning bed use on the behavior of subsequent melanomas.

METHODS

Cases of invasive cutaneous melanoma who completed a baseline questionnaire within 1 year of biopsy were ascertained using an institutional registry. Patients were categorized into one of two groups: (1) no history of UV tanning bed usage or (2) any history of tanning bed usage. Data analysis looked for group differences on the following variables: TNM staging, mitotic rate, family history of melanoma, and basic demographic variables.

RESULTS

Among 141 cases, a higher percentage of women (48.28%) reported tanning bed usage compared to men (26.51%, P < .01). Additionally, the average age at biopsy for people who reported tanning bed usage was significantly lower compared to those who had not reported using a tanning bed. There was no significant difference in stage at presentation (P = .56). Those with tanning bed usage presented significantly less often with melanoma of unknown primary (MUP). After controlling for the effects of gender and nodal status, tanning bed usage was not a significant independent predictor of 5 year overall survival.

CONCLUSIONS

If we remove the subject with MUP on the basis that more of these are mucosal in origin, lower TNM stage at presentation are found in patients with no tanning bed melanoma compared to those with history of tanning bed usage. In addition, tanning bed patients are younger and more likely female but with an equivalent mortality rate.

LEVEL OF EVIDENCE

Case Series.

Approach to Patients with Malignant Melanoma of Unknown Primary Origin

Objectives:

Although malignant melanoma accounts for 3% of skin cancers, it is responsible for 75% of deaths associated with skin cancer. In our study, all melanoma cases diagnosed and treated at our clinic were retrospectively reviewed, and the cases of unknown primary origin among them were examined in detail in terms of diagnosis and treatment.

Methods:

The patients with malignant melanoma treated at the inpatient services of our clinic between January 1991 and April 2017 were retrospectively screened in the records. These patients were evaluated for age, sex, tumor type, Breslow depth, metastasis, and treatment. Among these patients, four cases of unknown primary origin were examined in detail.

Results:

During January 1991 and April 2017, 173 patients received inpatient care for malignant melanoma at our clinic. As regards to the melanoma subtypes, nodular type in 45 patients, acral lentiginous type in 43 patients, superficial spreading type in 63 patients, lentigo maligna melanoma in 15 patients, subungual type in 7 patients, and either unidentified melanoma or other subtypes in 10 patients were identified.

Conclusion:

The ideal treatment of a patient with melanoma is multidisciplinary, with plastic surgery having a central role.

Melanoma of unknown primary

Formally described in the 1960s, melanoma of unknown primary (MUP) is characterized by the finding of metastatic melanoma within the lymph nodes, subcutaneous tissues, and other distant sites without an evident primary lesion. The most likely hypothesis of its etiology is an immune-mediated regression of the primary after metastasis has occurred. In addition, patients with MUP appear to have equivalent or better outcomes compared with patients with known primaries of a similar stage.

Primary Melanoma of the Third Metatarsal

Melanoma is a well-known malignant neoplasm of the skin, although it can also arise from other structures. Bone metastasis is not an uncommon event associated with melanoma, although primary osseous melanoma is very rare. In the present report, we describe a case of primary melanoma arising from the left third metatarsal in an adult male. The lesion was treated with surgical excision without adjunct chemotherapy, and recurrence developed approximately 12 months after the foot surgery. The patient died of the cancer 34 months after it had been identified. Primary melanoma arising in a metatarsal is rare, and we wished to highlight this unusual presentation.

Stage IV melanoma of unknown primary: A population-based study in the United States from 1973 to 2014

BACKGROUND

Melanoma of unknown primary (MUP) is incompletely described on a population level.

OBJECTIVE

We sought to characterize stage IV MUP in a population-based cancer registry.

METHODS

We developed a novel search algorithm to identify cases of stage IV MUP in the Surveillance, Epidemiology, and End Results 18 registries from 1973 to 2014. Cases of stage IV melanoma of known primary (MKP) served as a comparison group. Age-standardized incidence rates, demographic characteristics, adjusted disease-specific survival, and Cox proportional hazard models were calculated for MUP and MKP.

RESULTS

A total of 322 stage IV MUP cases and 12,796 stage IV MKP cases were identified in Surveillance, Epidemiology, and End Results 18 registries from 1973 to 2014. The incidence of stage IV MUP is increasing, particularly for patients younger than 30 years of age. In multivariate analyses, age older than 50 and a lack of surgical treatment were negative prognostic factors for stage IV MUP. Relative survival, but not 5-year adjusted disease-specific survival, was higher for stage IV MUP than for MKP.

LIMITATIONS

Limitations include the retrospective study design and possible misclassification of MUP.

CONCLUSIONS

The incidence of stage IV MUP is increasing, and stage IV MUP shares similar prognostic factors with stage IV MKP, including age and surgical treatment.

Metastatic melanoma of unknown primary in the temporalis muscle

Melanomas are aggressive cancers that present as cutaneous, mucosal and ocular lesions with the ability to metastasise widely. There are, however, occasions where lesions are found in distant sites such as lymph nodes, viscera and subcutaneous tissues without clinically apparent skin involvement. This is known as metastatic melanoma of unknown primary (MUP). Its presentation in skeletal muscle is rare, and the available literature is sparse. This article presents an 85-year-old woman with a MUP presenting in the right temporalis muscle, which was diagnosed with the aid of the ultrasound-guided core biopsy. The melanoma deposit was successfully excised, and no recurrence was identified. The patient is now under close follow-up.

Metastatic Melanoma of a MetatarsalA Case Report

A 53-year-old woman presented with painful swelling of the right forefoot presenting clinically as a metatarsal stress fracture. Radiographs showed destructive changes, and diagnostic imaging revealed an aggressive neoplasm. The lesion was biopsied, and the pathologic diagnosis was metastatic melanoma. A thorough physical examination and advanced imaging did not reveal a primary tumor. Ray resection was performed with en bloc resection of the neoplasm. The patient continues to receive long-term immune stimulation chemotherapy 34 months after the ray resection.

From melanocytes to melanomas

Melanomas on sun-exposed skin are heterogeneous tumours, which can be subtyped on the basis of their cumulative levels of exposure to ultraviolet (UV) radiation. A melanocytic neoplasm can also be staged by how far it has progressed, ranging from a benign neoplasm, such as a naevus, to a malignant neoplasm, such as a metastatic melanoma. Each subtype of melanoma can evolve through distinct evolutionary trajectories, passing through (or sometimes skipping over) various stages of transformation. This Review delineates several of the more common progression trajectories that occur in the patient setting and proposes models for tumour evolution that integrate genetic, histopathological, clinical and biological insights from the melanoma literature.

Primary Melanoma of Infra Temporal Fossa: A Case Report

This is the second case report in English literature of a primary non-cutaneous non mucosal melanoma (NCNM) originating from Infratemporal fossa (ITF). A 21 year woman who was previously treated for craniopharyngioma 14 years back with surgery and radiation, presented with left ITF swelling which after excision was histologically confirmed to be NCNM. She has been disease free till date. Therapeutic difficulties and diagnostic dilemmas in such a case are discussed. We propose the term of non cutaneous non mucosal melanoma (NCNM) for this rare entity.

Primary dermal melanoma: a West Australian cohort

BACKGROUND

The objectives of this study were to identify a subgroup of patients with putative primary dermal melanoma after thorough multidisciplinary clinical and histological evaluation, and to describe the clinical, histological and selected molecular features of these lesions.

METHODS

The records of the Western Australian Melanoma Advisory Service were searched for potential cases of primary dermal melanoma. The clinical and histological features were reviewed, immunohistochemical assessment was performed and clinical outcomes recorded.

RESULTS

Eighteen cases of putative primary dermal melanoma with available clinical data were identified. Two of 12 cases in which further histological sections could be obtained were excluded because of the presence of findings suggesting an epidermal origin on these further sections. In one additional case, such origin could not be histologically excluded. Median follow-up period for the remaining cases was 68 months. Confirmed primary dermal melanoma accounts for 0.87% of cases of melanoma referred to a subspecialist melanoma advisory service. These cases show significant histological overlap with dermal/subcutaneous metastases of melanoma, but display a relatively good prognosis, with a 5-year survival of 87.5%.

CONCLUSION

Our results support the recognition of a distinct group of melanoma that mimics metastatic melanoma, but is associated with a relatively favourable outcome. The group of putative primary dermal melanoma is likely to be heterogenous, including cases of primary nodular melanoma in which epidermal connection has not been identified, metastatic melanoma with an occult primary lesion and true primary dermal melanoma.

Acute Liver Failure Associated with Diffuse Hepatic Infiltration of Malignant Melanoma of Unknown Primary Origin

An 83-year-old man admitted for left hand pain due to a large necrotic ulcer presented with many sites of erythema on his trunk. Computed tomography revealed multiple poorly marginated masses in the liver; however, no malignant cells were detected on a biopsy of several skin lesions. He died on the 47th hospital day, and autopsy was subsequently performed, showing multiple nodules in the liver. The histological findings revealed clusters of malignant melanoma cells that had diffusely infiltrated the liver parenchyma. No tumor cells were detected in the skin lesions or lymph nodes. Immunohistochemically, the patient was diagnosed to have metastasis from malignant melanoma of unknown origin.

Utility of sentinel lymph node biopsy for solitary dermal melanomas

BACKGROUND AND OBJECTIVES

Solitary dermal melanoma (SDM) is melanoma confined to subcutaneous and/or dermal layers in the absence of a known primary cutaneous lesion. We hypothesized that sentinel node biopsy is an effective staging strategy for this rare disease.

METHODS

A Markov decision model was constructed to represent two management strategies for SDM: wide local excision followed by observation, and wide local excision followed by sentinel node biopsy. Utilities, likelihood of positive sentinel node biopsy, and cancer progression rates during a five year time horizon were assigned based on institutional data and a review of existing literature. Estimated costs were derived using Medicare reimbursements.

RESULTS

Excision followed by sentinel node biopsy provides greater utility, yielding 3.85 discounted quality-adjusted life years (dQALY) compared to 3.66 for excision alone. The incremental cost-effectiveness ratio for sentinel node biopsy is $19,102 per dQALY. Sensitivity analyzes demonstrated that observation is more cost-effective if greater than 23% of sentinel node biopsies are positive (16% reported), or if 5-year survival for observed patients is greater than 76% (69% reported).

CONCLUSIONS

Based on existing clinical evidence, sentinel node biopsy yields greater utility than excision alone and is cost-effective for patients presenting with solitary dermal melanoma.

Metastatic malignant melanoma of the inguinal lymph node with unknown primary lesion

Background. Malignant melanoma could present with metastasis with unknown primary (MUP) and this happens in 2-3% according to the studies. Around 90% of melanomas have cutaneous origin, but still there are melanomas that could be found in visceral organs or lymph nodes with unknown primary site. Spontaneous regression of the primary site could be an explanation. Case Report. We report a 58-year-old Caucasian male who presented with a right sided swelling in the inguinal region. Surgery was performed and biopsy showed metastatic malignant melanoma. No cutaneous lesions were identified by history or physical examination. Work up could not detect the primary lesion and patient was started on radiotherapy and immunotherapy. Conclusion. We present a case of malignant melanoma of unknown primary presenting in an unusual place which is the inguinal lymph node. Theories try to explain the pathway of development of such tumors and one of the theories mentions that it could be a spontaneous regression of the primary cutaneous lesion. Another theory is that it could be from transformation of aberrant melanocyte within the lymph node. Prognosis is postulated to be better in this case than in melanoma with a known primary.

Primary dermal melanoma: a unique subtype of melanoma to be distinguished from cutaneous metastatic melanoma: a clinical, histologic, and gene expression-profiling study

BACKGROUND

Primary dermal melanoma (PDM) is a subtype of melanoma confined to the dermis that may be morphologically impossible to distinguish from cutaneous metastatic melanoma (CMM).

OBJECTIVE

We sought to better characterize PDM by describing the clinical, histologic, and molecular features of 49 cases of PDM and determine whether a gene expression-profiling test could help distinguish PDM from CMM.

METHODS

We describe 49 cases of PDM and determined whether any clinical or histopathologic features had a statistically significant relationship with outcome. Secondly, we performed a melanoma gene expression-profiling test on a subset of the PDM and CMM cases.

RESULTS

Overall recurrence was infrequent and seen in 9 of 49 cases. Six patients had locoregional recurrences and 3 patients had distant metastasis. None of the clinical or histologic parameters showed a statistically significant relationship with recurrence. There was a statistically significant association of a class I signature by DecisionDx-Melanoma assay (Castle Biosciences Inc, Friendswood, TX) for PDM whereas CMM were more frequently class II (P value = .023).

LIMITATIONS

The mean follow-up time was 26 months.

CONCLUSIONS

Most conventional staging parameters used for prognosis in cutaneous melanoma have limited applicability to PDM. The melanoma prognostic assay may be a useful tool for distinguishing PDM from CMM.

S100 expression by atypical megakaryocytes: a previously unreported potential pitfall in dermatopathology

Several types of large atypical epithelioid cells can mimic tumoral melanocytes and can therefore be a source of misdiagnosis of melanoma. Megakaryocytes are one of these types, and are not frequently mentioned in the literature. In the current report, we present the case of a 76-year-old man presenting with acute panmyelosis with myelofibrosis. The bone marrow biopsy contained atypical megakaryocytes that expressed S100 in the cytoplasm. We discuss how such aberrant expression could be a source of some diagnostic problems in dermatopathology, including cutaneous melanoma, metastasis of melanoma in bone marrow and metastasis of melanoma in sentinel lymph nodes.

Metastatic melanomas of unknown primary show better prognosis than those of known primary: a systematic review and meta-analysis of observational studies

BACKGROUND

Melanoma of unknown primary (MUP) is a condition of metastatic melanoma without a primary lesion.

OBJECTIVE

We sought to identify the prognosis of MUP compared with melanoma of known primary (MKP).

METHODS

We searched for observational studies containing at least 10 patients with MUP from MEDLINE and EMBASE from inception to December 22, 2012. The outcomes of interest were overall and disease-free survival; meta-analyses of hazard ratio stratified by stage using a random effects model were performed. In addition, second systematic review identified risk factors influencing the survival of patients with MUP.

RESULTS

Eighteen studies including 2084 patients with MUP and 5894 with MKP were included. MUP had a better overall survival compared with MKP in stage III (15 studies; hazard ratio 0.83, 95% confidence interval 0.73-0.96, P = .010) and stage IV (6 studies; hazard ratio 0.85, 95% confidence interval 0.75-0.96, P = .008). Secondly, 22 studies including 3312 patients with MUP were reviewed, and increased stage and old age were the risk factors in patients with MUP.

LIMITATIONS

Diverse observational studies were reviewed, and selection and reporting biases are possible.

CONCLUSIONS

The current meta-analyses suggest better survival outcomes in patients with MUP than those in patients with MKP with the same corresponding tumor stage.

A rare case of metastatic malignant melanoma to the colon from an unknown primary

Metastatic melanoma from an unknown primary (MUP) is rare; its occurrence in the gastrointestinal tract is of exceedingly low prevalence. We report a case of a 73-year-old man with metastatic malignant melanoma to the colon from an unknown primary. The rarity of MUP and importance of screening for gastrointestinal metastasis in patients with malignant melanoma are discussed along with the role of surgical resection in improving prognosis and overall survival.

Molecular characterization and patient outcome of melanoma nodal metastases and an unknown primary site

Background

Melanoma of unknown primary site (MUP) is not a completely understood entity with nodal metastases as the most common first clinical manifestation. The aim of this multicentric study was to assess frequency and type of oncogenic BRAF/NRAS/KIT mutations in MUP with clinically detected nodal metastases in relation to clinicopathologic features and outcome.

Materials and Methods

We analyzed series of 103 MUP patients (period: 1992–2010) after therapeutic lymphadenectomy (LND): 40 axillary, 47 groin, 16 cervical, none treated with BRAF inhibitors. We performed molecular characterization of BRAF/NRAS/KIT mutational status in nodal metastases using direct sequencing of respective coding sequences. Median follow-up time was 53 months.

Results

BRAF mutations were detected in 55 cases (53 %) (51 V600E, 93 %; 4 others, 7 %), and mutually exclusive NRAS mutations were found in 14 cases (14 %) (7 p.Q61R, 4 p.Q61K, 2 p.Q61H, 1 p.Q13R). We have not detected any mutations in KIT. The 5-year overall survival (OS) was 34 %; median was 24 months. We have not found significant correlation between mutational status (BRAF/NRAS) and OS; however, for BRAF or NRAS mutated melanomas we observed significantly shorter disease-free survival (DFS) when compared with wild-type melanoma patients (p = .04; 5-year DFS, 18 vs 19 vs 31 %, respectively). The most important factor influencing OS was number of metastatic lymph nodes >1 (p = .03).

Conclusions

Our large study on molecular characterization of MUP with nodal metastases showed that MUPs had molecular features similar to sporadic non-chronic-sun-damaged melanomas. BRAF/NRAS mutational status had negative impact on DFS in this group of patients. These observations might have potential implication for molecular-targeted therapy in MUPs.

Melanoma patients with an unknown primary tumor site have a better outcome than those with a known primary following therapeutic lymph node dissection for macroscopic (clinically palpable) nodal disease

BACKGROUND

Several reports in the literature suggest a difference in outcome between melanoma patients with macroscopic (clinically palpable) nodal disease from an unknown primary (MUP) and a known primary (MKP). The purpose of this study was to compare the outcomes for MUP and MKP patients after therapeutic lymph node dissection (TLND) for macroscopic nodal disease.

METHODS

From a large, prospective, single-institution database, the details of melanoma patients who first presented with macroscopic nodal disease and underwent TLND between 1971 and 2010 were extracted and analyzed.

RESULTS

There were 287 MUP patients and 264 MKP patients who fulfilled the study selection criteria. MUP patients had better disease-free, distant metastasis-free, and melanoma-specific survival after their TLND than MKP patients (all p < 0.001). Extranodal melanoma extension, >3 positive lymph nodes, and administration of adjuvant radiotherapy were all independent predictors of reduced disease-free and melanoma-specific survival (all p < 0.05). MUP patients also had a better prognosis than MKP patients whose primary melanoma had regression (p = 0.001).

CONCLUSIONS

The occurrence and improved outcome of MUP patients may be due to immune-induced total regression of the primary tumor and better immunologic prevention or control of distant metastatic disease. Alternatively, in some MUP patients, melanoma may not be metastatic but may originate de novo from nevus cells in lymph nodes, with the more favorable prognosis attributable to their primary nodal origin and complete surgical resection.

Patients undergoing lymphadenectomy for stage III melanomas of known or unknown primary site do not differ in outcome

The outcome of patients with palpable melanoma metastases in lymph nodes in the presence (metastatic melanoma of known primary site, MKP) or absence (metastatic melanoma of unknown primary site, MUP) of an identifiable primary tumour remains controversial. Some of the previous studies contained large case series that included historical patients. We aimed to compare outcomes of those with MUPs versus MKPs with palpable lymph node invasion, after staging with modern imaging technology. Aprospective study of patients from a single tertiary institution who were undergoing lymph node dissection for palpable metastatic melanoma between 2000 and 2011 was conducted. All patients were ascertained by computerised tomography scanning and most diagnosed after 2004 had positron emission tomography scanning also. Clinicopathological details about the primary melanoma and lymph node dissections were gathered. Factors associated with recurrence and melanoma-specific mortality in those with MKP and with MUP were assessed using univariate and multivariate analyses. Out of 485 patients studied, 82 had MUP and 403 had MKP. Patients were followed up for a median of 17.4 and 19.0 months, for MKP and MUP, respectively. Five-year adjusted melanoma-specific survival was 58% for MUPs versus 49% for MKPs and was not significantly different between the two groups (adjusted Cox proportional Hazard ratio = 0.88 95% confidence interval [0.58, 1.33] p = 0.54). Previously established prognostic factors such as number of positive nodes and extracapsular extension were confirmed in both sets of patients. We conclude that among melanoma patients presenting with clinically detectable nodes, when accurately staged, those without an identifiable primary lesion have similar outcomes to patients with MKP.

Persistent painless hemospermia due to metastatic melanoma of the right seminal vesicle

BACKGROUND

Metastatic melanoma of the seminal vesicles is a very rare clinical entity and has been reported only once until today in a patient suffering from concomitant HIV infection 12 years ago.

CASE PRESENTATION

We report a case of persistent, painless hemospermia in a young Caucasian caused by metastatic malignant melanoma of the right seminal vesicle. The diagnosis was established by magnetic resonance imaging and transrectal ultrasound-guided biopsy. In the subsequent diagnostic workup the primary location of the tumor remained unknown but concomitant pulmonary, hepatic and supraclavicular lymph node metastases have been detected. Despite immediate chemotherapy initiation the patient finally succumbed to his progressive disease six months later.

CONCLUSIONS

Malignant melanoma should be considered as a rare differential diagnosis of hemospermia after common causes have been ruled out.

Melanoma patients with unknown primary site or nodal recurrence after initial diagnosis have a favourable survival compared to those with synchronous lymph node metastasis and primary tumour

Background

A direct comparison of prognosis between patients with regional lymph node metastases (LNM) detected synchronously with the primary melanoma (primary LNM), patients who developed their first LNM subsequently (secondary LNM) and those with initial LNM in melanoma with unknown primary site (MUP) is missing thus far.

Patients and Methods

Survival of 498 patients was calculated from the time point of the first macroscopic LNM using Kaplan Meier and multivariate Cox hazard regression analysis.

Results

Patients with secondary LNM (HR = 0.67; p = 0.009) and those with initial LNM in MUP (HR = 0.45; p = 0.008) had a better prognosis compared to patients with primary LNM (median survival time 52 and 65 vs. 24 months, respectively). A high number of involved nodes, the presence of in-transit/satellite metastases and male gender had an additional independent unfavourable effect.

Conclusions

Survival of patients with LNM in MUP and with secondary LNM is similar and considerably more favourable compared to those with primary LNM. This difference needs to be considered during patient counselling and for stratification purposes in clinical trials. The assumption of an immune privilege of patients with MUP which is responsible for rejection of the primary melanoma, and results in a favourable prognosis is not supported by our data.

Melanoma of unknown primary origin presenting as a rapidly enlarging adrenal mass

Metastasis to the adrenal can be seen in the context of metastatic melanoma, but primary adrenal melanoma is very uncommon. We present a case of a rapidly enlarging adrenal mass that mimicked non-functioning primary adrenal malignancies but later proved to be part of a widely metastatic melanoma of unknown primary origin. Careful physical examination of the patient led to the discovery of a subcutaneous metastatic focus that was not seen on [(18)F]-fluorodeoxyglucose positron emission tomography/CT imaging. The presence of subcutaneous metastases raised the suspicion for metastatic melanoma; however, pathological confirmation remained the ultimate tool to reach the final diagnosis.

Melanoma of unknown primary origin: a population-based study in the Netherlands

AIM

Few population-based studies have been published on melanoma of unknown primary origin (MUP). This study's aim is to describe characteristics and survival of MUP patients in the Netherlands, based on nationwide data from the Netherlands Cancer Registry (NCR).

METHODS

Patient and tumour characteristics of MUP patients were retrieved from the NCR. Subgroups were made according to metastatic site: nodal or distant. Survival rates were calculated using the Kaplan-Meier method. To obtain a better insight in the composition and prognosis of the MUP group, the survival was compared to that of patients with melanoma of a known primary origin (MKP), tumour-node-metastasis (TNM) stage III and IV.

RESULTS

Of all 33,181 melanoma patients diagnosed between 2003 and 2009, 2.6% (n=857) were diagnosed with MUP. MUP patients with nodal metastases had a similar survival as MKP stage III with macroscopic nodal involvement. After stratification according to the number of involved lymph nodes, the survival of patients with nodal metastases with one involved lymph node was not significantly different between MUP and MKP. The survival of MUP patients with two or more involved lymph nodes was slightly worse than that of MKP stage III patients with macroscopic nodal involvement with two or more involved lymph nodes. MUP patients with distant metastases had a similar survival as MKP stage IV. After stratification according to number of metastatic sites and metastatic site category, the survival in MKP stage IV patients with (sub)cutaneous metastases was slightly worse than MUP distant patients with (sub)cutaneous metastases.

CONCLUSIONS

The results of this study imply that MUP patients form a heterogeneous group, and that MUP patients with nodal metastases could be classified as stage III melanoma with macroscopic nodal involvement, and MUP patients with distant metastases as stage IV melanoma.

Melanoma of unknown primary as a cause of intestinal obstruction - a case description

Melanoma of unknown primary applies to 1-8% of all diagnosed melanomas, whereas primary melanoma of the small intestine is a extremely rare case. One of the melanoma characteristics is its capability of forming metastases in the small intestine which very often are diagnosed during autopsy.We present a case report of diagnosed melanoma of unknown primary, whose first symptom was intestinal obstruction. Before admission to the hospital cause of intestinal obstruction, the patient didn't present any signs and symptoms. All typical localizations of primary melanoma were excluded during diagnostic procedure. Palliative right hemicolectomy and segmental small intestine resection were performed. There were no complications in the postoperative course. On the ninth day the patient was discharged from hospital.Quick identification and radical resection of melanoma metastases in the alimentary tract may improve the survival rate in this group of patients. Resection, even if it is palliative by assumption, is not only the best method of elimination of persistent symptoms but it also gives hope for longer survival.

Primary dermal melanoma: a case report and a review of the literature

Patients with cutaneous metastatic melanoma of unknown primary origin (stage IV M1a disease according to the American Joint Committee on Cancer melanoma staging system) have an estimated 5-year survival rate of between 5% and 17.9% and a median survival of 6 months. However, certain patients with stage IV M1a disease have much higher survival rates. The existence of this subpopulation has given rise to the term primary dermal melanoma to describe such cases. We report a case of melanoma with characteristics consistent with primary dermal melanoma and review the relevant literature. A diagnosis of primary dermal melanoma requires careful clinical and pathologic correlation and should be considered in all patients with a solitary melanoma confined to the dermis and subcutaneous tissue when there is no evidence of a primary tumor or disease at other sites following appropriate staging studies. We believe that familiarity with this subtype of melanoma is essential in order to provide patients with optimal care and better prognostic information.

The 'epidemic' of melanoma between under- and overdiagnosis

In the past decades, the incidence of melanoma has been reported to rise in epidemic proportions. The chief reason for that pseudo-epidemic is improved criteria for diagnosis that allow melanomas to be recognized far more accurately and at earlier stages. The rising number of melanomas diagnosed has resulted in increased diagnostic scrutiny, more pigmented lesions being biopsied and more melanomas recognized, thus enhancing the 'epidemic' in self-perpetuating fashion. Regression of melanomas may, in part, explain why lesions undetected before did not result in a far higher mortality. Another potential reason for the disparity between increasing incidence of melanoma and relatively steady mortality may be overdiagnosis of melanoma. The latter may be curtailed by establishment of well-defined diagnostic categories, efforts to establish reliable criteria for recognition of those categories, better clinicopathologic correlation, postponement of biopsy of pigmented lesions in the case of irritation and excisional rather than incisional biopsies.

The Appearance of a Candidate Site for a Primary Melanoma: A 5 Year-gap with a Melanoma of an Unknown Site

Although more than 90% of melanomas have cutaneous origins, melanomas sometimes present metastatically with no apparent primary lesion. A 62-year-old female presented with black pigmentation on her left thumbnail that had begun 2 years earlier and after the biopsy, she was diagnosed with malignant melanoma. Interestingly, 7 years earlier, a 4 cm palpable mass on her left axilla had been diagnosed as melanoma from an unknown primary site (MUP) with the involvement of an axillary lymph node. We speculate that the melanoma of the left thumb was the primary site and the melanoma in the axilla was a metastasis from the left thumb, and suggest several hypotheses explaining the appearance of the primary lesion as acral lentiginous melanoma after detecting a metastatic site. We consider this case interesting because it helps us to understand the pathogenesis of MUP and reminds physicians to conduct careful periodical work-ups of melanoma patients, and highlights the importance of continued long-term follow-up, especially for patients with MUP.

Malignant gastrointestinal melanoma with an unknown primary

Malignant melanoma is rare in India; melanoma presenting as a metastatic disease with an unknown primary, involving the gastrointestinal tract without involving lymph nodes is extremely uncommon. We report a case of a 28-year-old male with a malignant melanoma metastasizing to stomach and liver with an unknown primary. Relevant literature is being reviewed.

A high proliferative index of recurrent melanoma is associated with worse survival

OBJECTIVE

Previous melanoma studies evaluating prognostic factors of survival at recurrence have focused on primary tumor characteristics and clinical variables at first recurrence. We examined the prognostic relevance of recurrent tumor proliferation.

METHODS

114 melanoma patients with available recurrent tissues who were prospectively enrolled at New York University Medical Center were studied. Standard of care prognostic variables (e.g. stage at initial diagnosis and lactate dehydrogenase level) and recurrent tissue expression of proliferative marker Ki-67 were evaluated for their association with overall survival.

RESULTS

High Ki-67 expression was observed in 57 (50%) of the 114 recurrent melanomas. On univariate analysis, the median overall survival of patients whose recurrent tumors overexpressed Ki-67 was significantly shorter than that of patients whose recurrent tumors had low Ki-67 expression (3.6 vs. 9.5 years, p = 0.03). On multivariate analysis, a high proliferative index of the recurrent melanoma remained an independent predictor of worse overall survival, controlling for stage at initial diagnosis, disease-free survival, and stage at first recurrence [HR = 2.09 (95% CI 1.24-3.54), p = 0.006].

CONCLUSIONS

Our results demonstrate the prognostic relevance of tumor proliferation in recurrent melanoma patients. Data also support restratification of risk assessment upon recurrence that considers tumor biology in addition to clinical variables evaluated as part of the standard of care.

Outcome after therapeutic lymph node dissection in patients with unknown primary melanoma site

PURPOSE

The aim of this study was to evaluate the incidence and outcome of melanoma of unknown primary site (MUP) after therapeutic lymph node dissection (TLND) of palpable nodal melanoma metastases. Disease-free (DFS) and overall survival (OS) time of MUP patients were analyzed and compared to patients undergoing a TLND for known primary melanomas (MKP).

METHODS

This single institution retrospective study analyzed 342 consecutive patients who were treated with 415 TLNDs for palpable nodal disease from 1982 to 2009. Univariate and multivariate analyses included: MUP versus MKP, gender, Breslow thickness, ulceration of primary tumor, site of primary tumor, site of dissection, extracapsular extension, number of collected nodes, number of positive nodes and the node positive ratio.

RESULTS

A total of 47 MUP were identified in 342 patients (13.7%). In univariate analysis, a trend was seen toward better survival for MUP patients compared to MKP patients having 5-year OS rates of 40% and 27%, respectively (P = 0.06). Multivariate analysis for OS showed two highly significant factors associated with worse prognosis: extracapsular extension and N3 status (both P < 0.001). Two factors were associated with a significant better prognosis: MUP (P = 0.03) and a neck dissection (P = 0.04).

CONCLUSIONS

Patients with MUP showed a statistically significant better OS compared to patients with melanoma metastases from known primary tumors. Presence of extracapsular extension and an increased number of positive nodes are statistically significantly negative prognostic factors for OS. The absence of a primary melanoma in stage III melanoma patients does not preclude surgery.

Malignant melanoma: from cell kinetics to micrometastases

Malignant melanoma (MM) micrometastases are basically seen in three locations inside the peritumoral dermis. They are localized (i) inside the interstitial sector of the dermal stroma; (ii) abutted to the external surface of the microvasculature; and (iii) more rarely present inside vascular channels. Single-cell and paucicellular micrometastases may be disclosed using immunohistochemistry even in the absence of larger microsatellites, which represent micronodular nests of metastatic cells. The presence of microsatellites is frequently tied to markers of MM aggressiveness including thickness and the Ki-67 index. Micrometastases may be present in the same conditions, but even as early as thin MM showing a small growth fraction. Microsatellites as well as micrometastases appear to predict locoregional extension and decreased relapse-free interval, but not distant metastasis and overall survival. These considerations have implications for patient care since patients with microsatellites and micrometastases are now included in the clinical stage III category of the disease. Their implication as a prognostic factor is not fully dependent on or linked to other markers of MM aggressiveness.

Metastasis in an orthotopic murine model of melanoma is independent of RAS/RAF mutation

Melanoma is the most lethal skin tumor in large part because of a propensity for early metastasis. Good models of this most clinically relevant feature of melanoma are lacking. Here, we report the development of an in-vivo model of metastasis that relies on orthotopic injection of green fluorescent protein-tagged lines in immunodeficient mice, serial intravital imaging of tumor progression, and quantification of distant spread by two-photon laser scanning microscopy, immunohistochemistry, and real-time PCR analysis. Using this system, we report an assessment of the in-vivo growth and metastatic properties of 11 well-characterized human melanoma cell lines. A subset of lines showed rapid in-vivo growth with invasion of host vasculature and distant seeding of viscera in this system. The ability to form metastasis in vivo did not correlate with three-dimensional collagen invasion in vitro. Surprisingly, similar lines in terms of molecular genetic events differed markedly in their propensity to metastasize to distant organs such as brain and lung. In particular, two lines harboring B-RAF mutation and high levels of phosphorylated ERK and AKT were reproducibly unable to form tumors after orthotopic injection. Similarly, two previously identified RAS/RAF wildtype 'epithelial like' lines that do not have elevated phosphorylated ERK and AKT or express TWIST1 mRNA still showed a pronounced ability for orthotopic growth and metastatic spread. All the metastatic cell lines in this model showed increased NEDD9 expression, but NEDD9 lentiviral overexpression did not convey a metastatic phenotype on nonmetastatic cells. These data suggest that melanoma metastasis is a molecularly heterogeneous process that may not require epithelial-to-mesenchymal transition or ERK activation, although both may facilitate the process.