Malignant melanoma of unknown primary site. To make the long story short. A systematic review of the literature

Metastasis-specific patterns of response and progression with anti-PD-1 treatment in metastatic melanoma

This study evaluated patterns of response as discerned by comprehensive metastasis-specific analysis in metastatic melanoma patients receiving anti-PD-1 antibodies. Bi-dimensional measurements of every metastasis in patients enrolled in the KEYNOTE-001 trial at a single institution were obtained at baseline and throughout treatment. Twenty-seven evaluable patients had 399 baseline metastases measurable on CT imaging. Complete response (CR) which occurred in 52.6% of metastases was smaller (mean 223 mm² versus 760 mm² , p < .01) and occurred more frequently in the lungs (65% versus 39.4%, p < .01). Response was heterogenous (new/progressing metastases alongside CR metastases) at first assessment in 4/14 patients with objective response (OR) as opposed to 7/13 patients with non-OR. CR of individual metastases is common and influenced by site and size. Most patients with OR demonstrate homogenous regression in all metastases at the first assessment. In contrast, patients with early heterogeneity had a poor outcome.

Primary Solitary Melanoma of the Lymphatic Nodes Or a Single Metastasis of Unknown Melanoma: Do We Need a New Staging System?

BACKGROUND

Malignant melanoma is a disease which has a cutaneous origin in 90% of the patients, but in rare cases, it could be discovered as secondary deposits with unknown primary site. Metastatic Malignant Melanoma occurs without a primary site in about 3% of all melanoma patients, and it could be divided into two main groups: metastatic lymph nodes' involvement or non-lymph nodes disease. The lack of unified classification and staging system, provided by AJCC (2009), as well as the lack for curtain diagnostic and therapeutic protocol, prompt us to raise the question what is the right way to precede in cases of metastasis of the lymph nodes, without evidence of a primary tumour?

CASE REPORT

We report a case of 67-years- old woman who presented in the dermatology clinic after a surgical removal of an enlarged lymph node in her left femoral area, verified histologically as a metastasis of melanoma. After a diagnostic refinement in the clinic, the diagnosis of metastasis of malignant melanoma was confirmed by histology revision. We use the presented case to create for the first time in the world literature a novel stereotype of thinking, which is also followed by a stereotype of clinical behaviour - gentle to the patient, but providing a certain amount of security and satisfaction for the medical staff.

CONCLUSION

The affection of a single lymph node in the absence of a primary tumour should not automatically lead to the conclusion that it is a single metastasis, but rather a primary melanoma of the lymph nodes, in cases of a negative PET scan, for example. In these cases, the measuring of the tumour thickness should guide the further therapeutic behaviour and determine the approach.

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.

Discrepancy in BRAF status among patients with metastatic malignant melanoma: A meta-analysis

The incidence of malignant melanoma is growing rapidly. Approximately half of the cases are BRAF mutated, making treatment with kinase inhibitors a (MEK and BRAF inhibitors) preferred choice in the advanced setting. The vast majority of these patients will benefit from the treatment. It is therefore of vital importance that the BRAF analysis is reliable and reflects the true nature of the tumour. Intraindividual tumour BRAF heterogeneity may exist, and changes of BRAF status over time might occur. We reviewed the literature by searching the PubMed database and 630 potentially relevant studies were identified. Thereafter, studies that investigated intralesional heterogeneity only, studies with ≤10 patients and studies that did not include adequate data to calculate discrepancy rates were excluded. Twenty-two studies met our inclusion criteria and were included in the meta-analysis. The pooled discrepancy rate between primary and metastatic lesions was 13.4% (95% confidence interval [CI]: 9.2-18.2%) while it was 7.3% (95% CI: 3.3-12.6) between two metastatic lesions. The number of patients whose tumoural BRAF status was changed from mutation to wild type and from wild type to mutation, respectively, was comparable. We conclude that a clinically meaningful discrepancy rate in BRAF status both between primary-metastatic and metastatic-metastatic melanoma lesions exists. Our results support the polyclonal model of melanomas in which subclones with different BRAF status co-exist in the same melanoma lesion. In addition, the results indicate a need for biopsy of a metastatic lesion for subsequent BRAF analysis when treatment with kinase inhibitors is considered.

Treatment Outcomes for Metastatic Melanoma of Unknown Primary in the New Era: A Single-Institution Study and Review of the Literature

BACKGROUND

Metastatic melanoma of unknown primary (MUP) is uncommon, biologically ill defined, and clinically understudied. MUP outcomes are seldom reported in clinical trials. In this study, we analyze responses of MUP patients treated with systemic therapy in an attempt to inform treatment guidelines for this unique population.

METHODS

New York University (NYU)'s prospective melanoma database was searched for MUP patients treated with systemic therapy. PubMed and Google Scholar were searched for MUP patients treated with immunotherapy or targeted therapy reported in the literature, and their response and survival data were compared to the MUP patient data from NYU. Both groups' response data were compared to those reported for melanoma of known primary (MKP).

RESULTS

The MUP patients treated at NYU had better outcomes on immunotherapy but worse on targeted therapy than the MUP patients in the literature. The NYU MUP patients and those in the literature had worse outcomes than the majority-MKP populations in 10 clinical trial reports.

CONCLUSIONS

Our study suggests that MUP patients might have poorer outcomes on systemic therapy as compared to MKP patients. Our cohort was small and limited data were available, highlighting the need for increased reporting of MUP outcomes and multi-institutional efforts to understand the mechanism behind the observed differences.

Genomic analysis of melanoma evolution following a 30-year disease-free interval

Ultra-late melanoma recurrence is infrequent, poorly understood and, in most cases, difficult to unambiguously distinguish from a new primary melanoma. We identified a patient with a second melanoma diagnosed after a 30-year disease-free interval, and sought to determine if this new lesion was a recurrence of the original melanoma. Here we report the genomic sequence analysis of the exomes of 2 melanoma lesions isolated from the same individual in 1985 and 2015, and their comparison to each other and to the germline DNA of the patient. Identification of many shared somatic mutations between these lesions proves a lineal relationship spanning 30 years. Unlike prior reports of ultra-late melanoma recurrence, the availability of the original tumor and the use of comprehensive genomic analysis allowed us to confirm that the second lesion is truly a recurrence. We demonstrate the acquisition of numerous additional mutations during the 3 decade asymptomatic period. These data highlight the low but very long-lasting risk of recurrence in this patient population.

Spindle Cell Melanoma and Interdigitating Dendritic Cell Sarcoma: Do They Represent the Same Process?

Intranodal spindle cell lesions on biopsy are problematic for a surgical pathologist, often requiring an extensive immunohistochemical evaluation with variable and frequently unsatisfactory results. In the absence of a history of malignancy, the differential diagnosis of a spindle cell tumor must include both a primary nodal proliferation and a metastatic process. Particularly challenging are those lesions that share morphologic and immunohistochemical features; spindle cell melanomas (SCM) and interdigitating dendritic cell sarcomas (IDCS) belong to this category. At present, electron microscopy is the only method proposed to distinguish between the 2 entities; however, this method is often unavailable and impractical. In this study, we assessed the comparative immunophenotypes of 18 cases of SCM and 8 cases of IDCS, with particular emphasis on the expression of MUM-1, β-catenin, SOX-10, MiTF, and p75. Our results showed nearly equivalent staining patterns and profiles; 12% and 17% of IDCS and SCM were labeled for MUM-1, 75% and 83% stained for β-catenin, 0% and 24% expressed MiTF, and 100% and 94% labeled for p75, respectively. All cases of IDCS and SCM displayed strong nuclear reactivity for SOX-10. On the basis of our study and pertinent literature, the morphologic and immmunophenotypic features of SCM and IDCS appear to be virtually indistinguishable from one another, raising the question as to whether these 2 entities represent a pathobiologically similar or even identical process.

PD-1 and PD-L1 inhibitors in melanoma treatment: past success, present application and future challenges

Anti-programmed death (PD)-1 antibodies have now become the standard of care for advanced melanoma, with two drugs gaining US FDA approval in recent years: nivolumab and pembrolizumab. Both have demonstrated significant activity and durable response with a manageable toxicity profile. Despite initial success, ongoing challenges include patient selection and predictors of response, innate resistance and optimizing combination strategies. In this overview, we take a closer look at the history and development of therapeutic targets to the PD-1/PD-ligand (L)1 pathway, clinical evidence, availability of biomarkers and their limitations in clinical practice and future strategies to improve treatment outcomes.

Intramammary metastatic melanoma of unknown primary origin in a 58-year old patient: a case report

BACKGROUND

Malignant melanoma metastasis to the breast is a rare disease.

CASE PRESENTATION

We present the case of a 58-year-old postmenopausal Caucasian woman with metastatic malignant melanoma of unknown origin of the right breast. She presented with a palpable lump in the inferior quadrant of her right breast. The investigations concluded it was breast metastasis from a malignant melanoma of unknown origin. The treatment consisted of mastectomy and axillary lymph node dissection. Two lymph nodes were positive for tumor cells and one showed extracapsular extension. Our patient did not receive immediate adjuvant therapy. Six weeks after the surgery, our patient presented a relapse in the right axilla (a 6 × 4 cm mass) with positive internal mammary lymph nodes and a single brain metastasis. This relapse motivated an adjuvant treatment with partial regression of the disease. Currently, our patient presents multiple metastases with poor prognosis.

CONCLUSIONS

From this experience, we advocate an immediate aggressive handling of melanoma metastasis to the breast.

Unusual presentation of melanoma of unknown primary origin: A case report and review of literature

Malignant melanomas often present with metastasis to regional lymph nodes. Patients are also known to present with metastatic nodes in the absence of a known primary. However metastatic melanoma involving the stomach is rare in the scenario of an unknown primary lesion. We present a case of a 41-year-old lady who was treated for nodal disease in the right axilla 8. months earlier with an unknown primary. She later presented to us with a recurrent right axillary swelling and on evaluation was found to also have a nodular deposit on the greater curvature of the stomach. Histopathology of the deposit in conjunction with immunohistochemical markers S.100P, Melan-A and HMB-45, confirmed the diagnosis of malignant melanoma. The patient underwent surgical excision of both lesions and is now on regular follow-up.

Evaluation of the pharmacokinetics and metabolism of pembrolizumab in the treatment of melanoma

INTRODUCTION

Advanced melanoma is a devastating disease that has propelled research in therapeutics beyond chemotherapy and radiotherapy. Being highly immunogenic, melanoma is a model tumor for immunotherapy and has highlighted the therapeutic potential of the immune checkpoint inhibitors.

AREAS COVERED

This review discusses the pharmacologic properties, clinical efficacy, and safety profile of pembrolizumab, an IgG4-kappa humanized monoclonal antibody against the programmed cell death protein 1 (PD-1) receptor, for the treatment of unresectable or metastatic melanoma.

EXPERT OPINION

Pembrolizumab was the first PD-1 inhibitor to be approved by the U.S. Food and Drug Administration (FDA). Remarkably, this accelerated approval for the treatment of advanced, heavily pretreated melanoma was based on response rates alone from a phase I trial. As anticipated, pembrolizumab confirmed a survival advantage in phase II and III trials and has led the way for the study of other drugs that share its mechanism of action. Defining disease and patient characteristics associated with a response remains amongst the most pressing priorities.

Cutaneous Melanoma with Brain Metastasis: Report of 193 Patients with New Observations

BACKGROUND

Brain metastasis is a common endpoint in patients suffering from malignant melanoma. However, little is known about factors that predispose to brain metastases.

OBJECTIVE

We performed a retrospective clinical and pathological investigation of melanoma patients with brain metastases in order to better characterise this patient population.

METHODS

193 melanoma patients with brain metastasis histologically diagnosed between 1990 and 2015 at the University Hospital Zurich were retrospectively identified and further specified for sex, age at diagnosis and detection of brain metastasis, and localisation. In addition, data were extracted regarding the subtype of primary melanoma, Breslow tumour thickness, Clark Level, mutation status, extent of metastatic spread and history of a second melanoma.

RESULTS

We found a significant male predominance (n = 126/193; 65%; p < 0.001). Breslow tumour thickness showed a wide range from 0.2 to 12.0 mm (n = 99; median 2.3 mm). 14 of 101 melanomas (14%) were classified as T1, thereof 11 (79%) were found in men. In 32 of 193 patients (17%), the primary melanoma was unknown.

CONCLUSIONS

Of special interest in our series is the high incidence of male predominance (79%) in cases of thin metastasing melanoma (14%), implicating genetic or epigenetic (hormonal) gender differences underlying tumour progression. Additionally, the high percentage of unknown primary melanoma (17%), at least partly representing completely regressed melanomas, indicates the importance of immune surveillance in melanoma progression.

The curious incident of 3 melanomas and their possible origins-A case report and review of literature

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The presence of a melanoma in the breast should prompt a close and meticulous search for a primary lesion and for potential signs of metastasis in nodal basins and common metastatic sites.

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Encapsulated subcutaneous nodules can be attributed to replaced lymph nodes or subcutaneous melanoma either secondary to metastasis from an unknown primary or as a primary dermal melanoma.

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Various permutations should be considered, especially in patients with atypical presentations such as ours, such that a suitably appropriate management and follow-up plan can be tailored.

Background

We describe an unusual case of 2 intra-parenchymal breast melanomas with a concomitant subcutaneous melanoma in the ipsilateral upper limb and no definite primary lesion.

Case report

Our patient is a 40-year-old Chinese female who presented with a breast lump in her left breast for which excision biopsy showed melanoma. A PET-CT revealed a second lesion in her breast. A left upper arm nodule with no overlying skin changes was also noted. She underwent a mastectomy and excision biopsy of the upper arm nodule. Histology showed that the second breast lesion was also a melanoma, while the arm nodule contained melanoma cells within a fibrous capsule.

Conclusion

The presence of a melanoma in the breast should prompt a close and meticulous search for a primary lesion and potential signs of metastasis. Encapsulated subcutaneous nodules can be attributed to replaced lymph nodes or subcutaneous melanoma which can be either primary dermal melanoma or metastasis from an unknown primary.

Metastases of Melanoma to Head and Neck Mucosa: A Report of Short Series

Objectives

Metastasis of melanoma to the head and neck mucosa is a very unusual condition. The aim of this study was to report four cases of patients with metastatic melanoma in the head and neck mucosa treated at a single institution.

Methods

Clinical data were obtained from the medical records. All cases were histologically reviewed to confirm the diagnosis, and immunohistochemical reactions were performed in the cases submitted to biopsy.

Results

All patients were males and the mean age was 40.5 years old. The sites of the metastatic tumors were gingival mucosa, floor of the mouth, oropharynx, and larynx. Two tumors appeared as submucosal nodules with normal color; one lesion was a blackish nodular lesion, and one was shown to be an ulcerated lesion. The size of tumors ranged from 2.0 to 4.0 cm. All patients had developed systemic disease at time of diagnosis of metastatic tumor in the head and neck mucosa. Survival rates ranged from 2 to 19 months after the diagnosis of the metastatic mucosal melanoma in the head and neck region.

Conclusion

Although rare, patients with melanoma must be closely and regularly followed up, with careful routine examination of head and neck, because metastatic tumors in this region seem to be part of a lethal widespread metastatic disease.

Open-label, multicenter, single-arm phase II DeCOG-study of ipilimumab in pretreated patients with different subtypes of metastatic melanoma

BACKGROUND

Ipilimumab is an approved immunotherapy that has shown an overall survival benefit in patients with cutaneous metastatic melanoma in two phase III trials. As results of registrational trials might not answer all questions regarding safety and efficacy of ipilimumab in patients with advanced melanoma seen in daily clinical practice, the Dermatologic Cooperative Oncology Group conducted a phase II study to assess the efficacy and safety of ipilimumab in patients with different subtypes of metastatic melanoma.

PATIENTS AND METHODS

We undertook a multicenter phase II study in melanoma patients irrespective of location of the primary melanoma. Here we present data on patients with pretreated metastatic cutaneous, mucosal and occult melanoma who received up to four cycles of ipilimumab administered at a dose of 3 mg/kg in 3 week intervals. Tumor assessments were conducted at baseline, weeks 12, 24, 36 and 48 according to RECIST 1.1 criteria. Adverse events (AEs), including immune-related AEs were graded according to National Cancer Institute Common Toxicity Criteria (CTC) v.4.0. Primary endpoint was the OS rate at 12 months.

RESULTS

103 pretreated patients received at least one dose of ipilimumab, including 83 cutaneous, seven mucosal and 13 occult melanomas. 1-year OS rates for cutaneous, mucosal and occult melanoma were 38 %, 14 % and 27 %, respectively. Median OS was 6.8 months (95 % CI 5.3-9.9) for cutaneous, 9.6 months (95 % CI 1.6-11.1) for mucosal, and 9.9 months (lower 95 % CI 2.3, upper 95 % CI non-existent) for occult melanoma. Overall response rates for cutaneous, mucosal and occult melanoma were 16 %, 17 % and 11 %, respectively. Eleven patients had partial response (16 %) and ten patients experienced stable disease (14 %), none achieved a complete response. Treatment-related AEs were observed in 71 patients (69 %), including 20 grade 3-4 events (19 %). No new and unexpected safety findings were noted.

CONCLUSIONS

Ipilimumab is a treatment option for pretreated patients with advanced cutaneous melanoma seen in daily routine. Toxicity was manageable when treated as per protocol-specific guidelines.

TRIAL REGISTRATION

Clinical Trials.gov NCT01355120.

Treatment of Regional Metastatic Melanoma of Unknown Primary Origin

(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.

Primary Pulmonary Malignant Melanoma: An Unexpected Tumor

Malignant melanoma occurs most frequently on the skin. However, it can also arise in other organs and tissues of the body. Primary pulmonary malignant melanoma is a very rare non-epithelial neoplasm accounting for 0.01% of all primary pulmonary tumors. The treatment of choice is surgical resection of the tumor with an oncologically adequate margin as in lobectomy or pneumonectomy. The prognosis of this condition is rather poor. Based on previous data, its 5-year survival is at least 10%. Here, we report a case of an 82-year-old woman whose primary pulmonary melanoma was detected incidentally.

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.

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.

[Ways to personalized medicine for gastric cancer]

Gastric cancer is the fourth most common tumor and the second most common cause of cancer-related deaths in the world. Approximately 70 % of the patients already have lymph node metastases at the time of the diagnosis leading to a median overall survival time of 16.7 months. Complete resection of the primary tumor with D2 lymphadenectomy offers the only chance of cure in the early stages of the disease. Survival of more locally advanced gastric cancer was improved by the introduction of perioperative, adjuvant and palliative chemotherapy of gastric cancer; however, the identification of novel predictive and diagnostic targets is urgently needed. Our own studies on gastric cancer biology identified several putative tumor biologically relevant G-protein-coupled receptors (e.g. AT1R, AT2R, CXCR4, FZD7, LGR4, LGR5, LGR6). Some of these receptors are also putative stem cell markers and may serve as future targets of an individualized therapy of gastric cancer.

Metastatic Tumors of Unknown Origin: Ancillary Testing in Cytologic Specimens

The application of ancillary studies, such as immunostains, to cytopathology has improved the ability to make accurate diagnoses with precise subclassification. Even with these techniques, there are still aspiration and exfoliative cytology cases for which it remains difficult to definitively determine the source and/or subtype. This article focuses on the well-established and novel ancillary studies used in the modern era of cancer diagnoses in cytopathology, particularly in the diagnostic work-up of metastatic tumors without a known primary.

Rhabdomyoblastic differentiation in metastatic melanoma: making sense of a rare but complex form of mimicry

A case of melanoma with rhabdomyoblastic differentiation is presented in the context of the previously reported cases. The emerging literature seeking to identify the molecular basis of rhabdoid and rhabdomyoblastic differentiation, as well as their poor prognosis, is reviewed. The combination of a diverse range of morphology and the potential for spontaneous primary tumor regression, despite metastasis, makes the accurate diagnosis of melanoma challenging. Histopathology review is often recommended in these cases, as is referral to a specialized cancer center for discussion in a multidisciplinary meeting. Improved recognition of this rare pattern of melanoma morphology may provide the means for omics-based techniques to identify novel therapeutic targets to improve the prognostic outlook for these patients.

Malignant melanoma of the ileo-anal pouch anastomosis after restorative proctocolectomy for ulcerative colitis: report of a case

A 62 year-old patient with therapy-refractory pouchitis after proctocolectomy for ulcerative colitis was admitted with hematochezia and abdominal discomfort. A malignant melanoma (MM) was found after repeated biopsies of the pouch. Complete staging revealed no evidence for distant metastases and the patient underwent abdominoperineal pouch resection. Six weeks later, the patient was readmitted because of severe general deterioration and diffuse metastatic spread to the liver was found. The patient died of hepatorenal syndrome shortly thereafter.

Patients with inflammatory bowel disease are at increased risk of developing cancer, including rarities such as MM. Our experience stresses the importance of repeated biopsies in therapy-refractory pouchitis.

Melanomas of unknown primary have a mutation profile consistent with cutaneous sun-exposed melanoma

Melanoma of unknown primary (MUP) is an uncommon phenomenon whereby patients present with metastatic disease without an evident primary site. To determine their likely site of origin, we combined exome sequencing from 33 MUPs to assess the total rate of somatic mutations and degree of UV mutagenesis. An independent cohort of 91 archival MUPs was also screened for 46 hot spot mutations highly prevalent in melanoma including BRAF, NRAS, KIT, GNAQ, and GNA11. Results showed that the majority of MUPs exhibited high somatic mutation rates, high ratios of C>T/G>A transitions, and a high rate of BRAF (45 of 101, 45%) and NRAS (32 of 101, 32%) mutations, collectively indicating a mutation profile consistent with cutaneous sun-exposed melanomas. These data suggest that a significant proportion of MUPs arise from regressed or unrecognized primary cutaneous melanomas or arise de novo in lymph nodes from nevus cells that have migrated from the skin.

Colocalization of inflammatory response with B7-h1 expression in human melanocytic lesions supports an adaptive resistance mechanism of immune escape

Although many human cancers such as melanoma express tumor antigens recognized by T cells, host immune responses often fail to control tumor growth for as yet unexplained reasons. Here, we found a strong association between melanocyte expression of B7-H1 (PD-L1), an immune-inhibitory molecule, and the presence of tumor-infiltrating lymphocytes (TILs) in human melanocytic lesions: 98% of B7-H1(+) tumors were associated with TILs compared with only 28% of B7-H1(-) tumors. Indeed, B7-H1(+) melanocytes were almost always localized immediately adjacent to TILs. B7-H1/TIL colocalization was identified not only in melanomas but also in inflamed benign nevi, indicating that B7-H1 expression may represent a host response to tissue inflammation. Interferon-γ, a primary inducer of B7-H1 expression, was detected at the interface of B7-H1(+) tumors and TILs, whereas none was found in B7-H1(-) tumors. Therefore, TILs may actually trigger their own inhibition by secreting cytokines that drive tumor B7-H1 expression. Consistent with this hypothesis, overall survival of patients with B7-H1(+) metastatic melanoma was significantly prolonged compared with that of patients with B7-H1(-) metastatic melanoma. Therefore, induction of the B7-H1/PD-1 pathway may represent an adaptive immune resistance mechanism exerted by tumor cells in response to endogenous antitumor activity and may explain how melanomas escape immune destruction despite endogenous antitumor immune responses. These observations suggest that therapies that block this pathway may benefit patients with B7-H1(+) tumors.

Primary biliary tract melanoma: Report of a case and review of the literature

INTRODUCTION

Primary melanoma of the bile duct is extremely rare with only nine cases of primary melanoma of the bile duct reported in the literature.

PRESENTATION OF CASE

A 55-year-old previously healthy gentleman developed increasing jaundice over several months and subsequently underwent an ERCP with stone extraction. Cytology brushings in an area of a distal stricture in the bile duct were concerning for cholangiocarcinoma. The patient was referred to our institution and underwent a pancreaticoduodenectomy. The surgical specimen showed a single 4.5cm polypoid lesion located in the bile duct. A diagnosis of melanoma was rendered after immunohistochemical studies on the tumor demonstrated positivity for melanoma markers. Follow-up of the patient with skin, ocular, and lymph node exams showed no evidence of melanoma. A PET scan 4 and 10 months post-surgery failed to reveal either a primary skin lesion or other sites of metastases.

DISCUSSION

The vast majority of melanomas of the bile duct represent metastases from a cutaneous source and tend to present as multiple flat pigmented lesions. Conversely, cases of primary bile duct melanoma are characterized by a distinct gross morphology consisting of a solitary intraluminal polypoid lesion attached by a pedicle with no other identifiable primary lesion. Other supporting criteria include absence of other involved sites and presence of an in situ junctional component.

CONCLUSION

Given the clinical history, gross findings, and lack of a primary cutaneous site or other demonstrable metastases, this patient likely represents the tenth reported case of primary biliary tract melanoma.

Colocalization of inflammatory response with B7-h1 expression in human melanocytic lesions supports an adaptive resistance mechanism of immune escape

Although many human cancers such as melanoma express tumor antigens recognized by T cells, host immune responses often fail to control tumor growth for as yet unexplained reasons. Here, we found a strong association between melanocyte expression of B7-H1 (PD-L1), an immune-inhibitory molecule, and the presence of tumor-infiltrating lymphocytes (TILs) in human melanocytic lesions: 98% of B7-H1(+) tumors were associated with TILs compared with only 28% of B7-H1(-) tumors. Indeed, B7-H1(+) melanocytes were almost always localized immediately adjacent to TILs. B7-H1/TIL colocalization was identified not only in melanomas but also in inflamed benign nevi, indicating that B7-H1 expression may represent a host response to tissue inflammation. Interferon-γ, a primary inducer of B7-H1 expression, was detected at the interface of B7-H1(+) tumors and TILs, whereas none was found in B7-H1(-) tumors. Therefore, TILs may actually trigger their own inhibition by secreting cytokines that drive tumor B7-H1 expression. Consistent with this hypothesis, overall survival of patients with B7-H1(+) metastatic melanoma was significantly prolonged compared with that of patients with B7-H1(-) metastatic melanoma. Therefore, induction of the B7-H1/PD-1 pathway may represent an adaptive immune resistance mechanism exerted by tumor cells in response to endogenous antitumor activity and may explain how melanomas escape immune destruction despite endogenous antitumor immune responses. These observations suggest that therapies that block this pathway may benefit patients with B7-H1(+) tumors.

Survival in cancer of unknown primary site: population-based analysis by site and histology

BACKGROUND

Cancer of unknown primary (CUP) is diagnosed at a metastatic stage, conferring an unfavorable prognosis. The natural history of the disease is poorly understood, which complicates diagnosis, treatment and follow-up. Population-based survival data are lacking regarding location and histology of metastases.

PATIENTS AND METHODS

From the Swedish Cancer Registry, 18 911 CUP patients were identified between years 1987 and 2008. Survival was analyzed by Kaplan-Meier survival curves and Cox regression.

RESULTS

Adenocarcinoma accounted for 70% of all extranodal cases with a 12-month survival of 17% and the median survival of 3 months. Adenocarcinoma was also the most common histology (33.4%) when metastases were limited to lymph nodes, with a 12-month survival of 41% and median survival of 8 months. For extranodal metastases, the extremes in survival were small intestinal cancer with poor prognosis and mediastinal cancer with favorable prognosis. For nodal metastases, patients affected in the head and neck, axillary and inguinal regions had the best prognosis and those with abdominal and intrapelvic metastases the worst prognosis.

CONCLUSIONS

The present data underline the importance of histology and location of metastasis in assisting clinical decision making: hazard ratios differed by a factor of five among extranodal and nodal metastases.

Clear Cell Tumors of Soft Tissue

Clear cell lesions of soft tissue include varying morphologic patterns and a range of clinical behaviors and prognoses. Benign lesions include perivascular epithelioid cell tumors, clear cell fibrous papule, and distinctive dermal clear cell mesenchymal tumor; malignant tumors include clear cell sarcoma, liposarcoma, and rare malignant perivascular epithelioid cell tumors. Clear cell variants of other benign and malignant soft tissue tumors include fibrous histiocytoma, atypical fibroxanthoma, myoepithelioma, leiomyoma and leiomyosarcoma, and rhabdomyosarcoma. Metastatic clear cell tumors, including renal cell carcinoma and adrenal cortical carcinoma, should be considered in the differential diagnosis and excluded through clinical history, imaging studies, and immunohistochemical stains.

Insights into the Role of PAX-3 in the Development of Melanocytes and Melanoma

Melanoma is the deadliest form of skin cancer in the United States with an increasing prevalence. However, the development of melanoma from a melanocyte precursor is still poorly defined. Understanding the molecules responsible for melanoma progression may lead to improved targeted therapy. One potential molecule is the paired box-3 (PAX-3) protein, which has been implicated in the development of melanocytes and malignant melanoma. In melanoma, the expression of PAX-3 is believed to be differentially regulated, and has been linked with malignancies and staging of the disease. The loss of PAX-3 regulation has also been associated with the loss of transforming growth factor-beta (TGF-β) activity, but its effect on PAX-3 in differentiated melanocytes as well as metastatic melanoma remains unclear. Understanding PAX-3 regulation could potentially shift melanoma to a less aggressive and less metastatic disease. This review summarizes our current knowledge on PAX-3 during melanocyte development, its regulation, and its implications in the development of novel chemo-immunotherapeutics against metastatic melanoma.