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

Report on a case of liver-originating malignant melanoma of unknown primary

Malignant melanoma (MM) frequently occurs in the skin or mucosa, whereas malignant melanoma of unknown primary (MUP) is diagnosed in patients with lymph nodes or visceral organs as the site of origin, where it is challenging to detect the primary lesion by comprehensive examination. MUP is possibly related to the spontaneous regression of the primary lesion. In addition, primary hepatic melanoma (PHM) usually refers to the primary MM occurring in the liver, with no typical primary lesions and no manifestations of tumor metastasis. A 61-year-old male patient with liver as the site of origin was diagnosed with MM by Melan-A, HMB-45, and S-100 immunohistochemistry staining of liver biopsy tissue. Based on a comprehensive examination, no basis was found for melanoma in sites such as the skin, mucosa, five sense organs, brain, digestive tract, respiratory tract, or genitalia, and the patient was subsequently diagnosed with MUP. MMs require a comprehensive inspection, beginning with the liver, to search for the primary lesion; if the primary lesion is not found, the possibility of PHM or MUP should be considered.

Leptomeningeal Disease and Hydrocephalus as the First Presentation of Melanoma

We present a case of an 83-year-old man who developed acute hydrocephalus as the first presentation of leptomeningeal disease secondary to melanoma of unknown primary, which is an exceedingly rare subtype of melanoma, in addition to a very rare complication of malignancy in general, which was diagnosed with imaging as well as cytology modalities. This presentation is rare and highlights the importance of recognizing this condition.

Outcomes in organ transplants from donors with melanoma: a systematic review

Melanoma transmitted through organ transplantation is an increasingly reported event. Immunosuppression increases the risk of melanoma; however, transmission of malignancy from transplanted organs is a distinct etiology of melanoma occurrence. The risk of transmission of melanoma from an organ donor with melanoma has yet to be determined. The authors aimed to investigate this phenomenon by reviewing the outcomes of patients that received organs from donors with melanoma. A systematic literature review was conducted with emphasis on identifying organ donors with known histories of melanoma and reported information regarding recipients of their organs. The databases PubMed, MEDLINE, Embase, and JBI EBP were searched in January 2023. Search terms included "melanoma," terms for solid organs, "donor," "transplant," "transmission," and their variations as well as terms related to temporal relations. Inclusion criteria were articles that stated outcomes in organ recipients from donors that had a diagnosis of melanoma either pretransplant or postmortem. Reference lists of selected articles were hand searched for further studies. A total of 232 articles were identified from the search parameters. After applying inclusion and exclusion criteria, 13 articles were selected. Hand searching the references of these articles yielded four additional articles. Of the 75 organ recipients that received organs from donors with known melanoma, 43 developed melanoma. While a definitive quantitative risk cannot be ascertained based on our review, the numerous reported cases of melanoma in organ recipients from donors that have melanoma should still be considered by clinicians.

Primitive rectal melanoma: A rare case report

Mucosal melanoma is a rare subtype of melanoma distinct from the cutaneous type in its clinical and biological aspects, requiring different therapeutical management. Anorectal melanomas represent less than 1% of anorectal cancers and 0.3% of malignant melanomas, and they are by far the most studied type. Proctologic examination, colonoscopy, and biopsy can establish a correct diagnosis. Imaging techniques, especially MRI can show some characteristic features, but it is essentially performed for extension assessment. We report the case of a 63-year-old man who consulted for rectal bleeding. The proctological examination found a brownish ulcerative-vegetating tumor of 3 cm in diameter located 3 cm from the anal rim. The endoscopic examination revealed a predominance of ulcerative budding lesions and the biopsy specimen confirmed a rectal melanoma. The extension assessment, based on a computed tomography scan and MRI did not show locoregional or distant metastases. Radiotherapy and abdominoperineal resection with pelvic node dissection was the treatment of choice with good evolution.

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.

Impact of systemic therapies in metastatic melanoma of unknown primary: A study from MELBASE, a French multicentric prospective cohort

BACKGROUND

Clinical outcomes of advanced melanoma of unknown primary (MUP) in the era of novel therapies have been scarcely studied.

OBJECTIVE

To investigate the efficacy and safety of systemic treatments in patients with advanced MUP compared to patients with stage-matched melanoma of known cutaneous primary (cMKP).

METHODS

Based on the nationwide MelBase prospective database, this study included advanced melanoma patients treated from March 2013 to June 2021 with first-line immunotherapies, targeted therapies, or chemotherapy. Co-primary outcomes were progression-free survival and overall survival. Secondary outcome was treatment-related toxicities. Multivariate and propensity score analyses were performed.

RESULTS

Of 1882 patients, 265 (14.1%) had advanced MUP. Patients with advanced MUP displayed more often unfavorable initial prognostic factors than those with cMKP. Progression-free and overall survival did not differ significantly between the groups (P = .73 and P = .93, respectively), as well as treatment-related toxicity rate and severity, regardless of treatment type.

LIMITATIONS

No record of standard diagnostic criteria of MUP used in the participating centers.

CONCLUSIONS

Although patients with MUP had less favorable baseline prognostic factors, they benefited from the novel therapies as much as those with cMKP. They should be managed according to similar strategies.

Proton beam therapy for cervical lymph node metastasis in an octogenarian with melanoma of unknown primary: a case report

An 80-year-old man with an approximately 3-cm mass in the right submandibular region presented to our institution. Magnetic resonance imaging revealed enlarged lymph nodes (LNs) in the right neck, and fluorine-18-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) indicated positive FDG accumulation in the right neck LNs only. Excisional biopsy was performed for suspected malignant lymphoma, and the biopsy revealed melanoma. Close examination of the skin, nasal cavity, oral pharyngeal and laryngeal cavities, and gastrointestinal tract were performed. No primary tumor was detected by these examinations, and the patient was diagnosed with cervical LN metastasis from melanoma of unknown primary of clinical stage T0N3bM0 stage IIIC. The patient refused cervical neck dissection because of his age and comorbidity of Alzheimer's disease and instead opted for proton beam therapy (PBT) at a total dose of 69 Gy (relative biological effectiveness) in 23 fractions. He did not receive any systemic therapy. The enlarged LNs shrunk slowly, and FDG PET/CT at 1 year after PBT showed that the right submandibular LN had shrunk from 27 to 7 mm in length, and there was no significant FDG accumulation. At 6 years and 4 months after PBT, the patient is alive without any recurrence.

Increased Early Cancer Diagnosis: Unveiling Immune-Cancer Biology to Explain Clinical "Overdiagnosis"

Even though clinically small 'early' cancers represent many millions of cells biologically, when removed surgically, these often never recur or regrow, nor reduce the individual's lifespan. However, some early cancers remain quiescent and indolent; while others grow and metastasize, threatening life. Distinguishing between these different clinical behaviours using clinical/pathological criteria is currently problematic. It is reported that many suspicious lesions and early cancers are being removed surgically that would not threaten the patient's life. This has been termed 'overdiagnosis', especially in the sphere of cancer screening. Although a controversial and emotive topic, it poses clinical and public health policy challenges. The diagnostic differentiation between 'non-lethal' and 'lethal' tumor forms is generally impossible. One perspective gathering evidential support is that a dynamic balance exists between the immune response and malignant processes governing 'lethality', where many more cancers are produced than become clinically significant due to the immune system preventing their progression. Higher medical screening "diagnosis" rates may reflect lead-time effects, with more 'non-progressing' cancers detected when an early immune-cancer interaction is occurring. We present a model for this immune-cancer interaction and review 'excess' or 'overdiagnosis' claims that accompany increasingly sensitive diagnostic and screening technologies. We consider that immune tools should be incorporated into future research, with potential for immune system modulation for some early cancers.

Safety and efficacy of Pucotenlimab (HX008) - a humanized immunoglobulin G4 monoclonal antibody in patients with locally advanced or metastatic melanoma: a single-arm, multicenter, phase II study

BACKGROUND

Pucotenlimab is a novel recombinant humanized anti-PD-1 (Programmed death-1) monoclonal antibody, which belongs to the human IgG4/kappa subtype, and can selectively block the binding of PD-1 with its ligands PD-L1 and PD-L2.

METHODS

In this phase 2 trial, patients with locally advanced or metastatic melanoma who had failed conventional treatment (chemotherapy, targeted therapy, interferon, IL-2, et al.) were recruited. The patients were administrated with Pucotenlimab of 3 mg/kg every 3 weeks until disease progression, intolerable toxicity, or treatment discontinuation for any other reasons. The primary endpoint was the overall response rate (ORR). The secondary endpoints were disease control rate (DCR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and toxicity.

RESULTS

One-hundred and nineteen patients were enrolled and followed up for 19.32 (ranging from 15.901 to 24.608) months by the cutoff date of July 30^th, 2021. The ORR was 20.17% (24/119, 95% CI, 13.370%-28.506%) based on both independent review committee (IRC) and the investigator's assessment per RECIST v1.1. The median PFS were 2.89 (95% CI, 2.037-4.074) months and 2.46 (95% CI, 2.004-4.008) months based on IRC and investigator's assessment, respectively, per RECIST v1.1. The median OS was 16.59 (95% CI, 13.963-26.973) months. Treatment-related adverse events (TRAEs) occurred in 77.3% (92/119) of the patients. The incidence of Grade ≥ 3 TRAEs was 15.1% (18/119). In addition, none of the patients died because of TRAEs. As for biomarker analysis, Eotaxin (CCL11) and MCP-1 (CCL2) were related to treatment response, while TNF-α and VEGF were related to treatment failure.

CONCLUSIONS

Pucotenlimab as a ≥ 2^nd line therapy showed promising efficacy and tolerable toxicity for patients with locally advanced or metastatic melanoma.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT04749485 (registered retrospectively on 11/02/2021).

A rare case of endobronchial melanoma of unknown primary

A 62-year-old man who presented with complaints of cough and hemoptysis was found to have an endobronchial tumor which obstructed the lingular bronchus. Histopathologic examination of a bronchoscopic biopsy of the tumor was consistent with malignant melanoma. Skin, mucosal, and eye examinations failed to detect the primary site of melanoma and the patient was diagnosed with endobronchial melanoma of unknown primary (MUP). Although the patient underwent a curative surgical resection, recurrence was detected in 4 months. Endobronchial MUP is a rare presentation of melanoma and better therapeutic strategies need to be established.

Pitfalls in Cutaneous Melanoma Diagnosis and the Need for New Reliable Markers

Cutaneous melanoma is one of the most aggressive forms of skin cancer, with the development of advanced stage disease resulting in a high rate of patient mortality. Accurate diagnosis of melanoma at an early stage is essential to improve patient outcomes, as this enables treatment before the cancer has metastasised. Histopathologic analysis is the current gold standard for melanoma diagnosis, but this can be subjective due to discordance in interpreting the morphological heterogeneity in melanoma and other skin lesions. Immunohistochemistry (IHC) is sometimes employed as an adjunct to conventional histology, but it remains occasionally difficult to distinguish some benign melanocytic lesions and melanoma. Importantly, the complex morphology and lack of specific biomarkers that identify key elements of melanoma pathogenesis can make an accurate confirmation of diagnosis challenging. We review the diagnostic constraints of melanoma heterogeneity and discuss issues with interpreting routine histology and problems with current melanoma markers. Innovative approaches are required to find effective biomarkers to enhance patient management.

Long Noncoding RNA LINC02249 Is a Prognostic Biomarker and Correlates with Immunosuppressive Microenvironment in Skin Cutaneous Melanoma

Skin cutaneous melanoma (SKCM) is one of the most aggressive and life-threatening tumors. It has a high incidence rate, as well as significant metastasis and fatality rates. To successfully treat SKCM and to increase the overall survival rate, early identification and risk stratification are both absolutely necessary. Long noncoding RNAs (lncRNAs) play a significant regulatory role in a variety of cancers. However, the expression and function of many lncRNAs have not been investigated. We evaluated the expression profile of the long noncoding RNA LINC02249 (LINC02249) in pan-cancers by using data on gene expression obtained from TCGA and GTEx. The biological function of LINC02249 was determined by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The prognostic value of LINC02249 expression in SKCM patients was statistically analyzed. Besides, the ssGSEA approach was utilized in order to investigate the degree to which LINC02249 expression is correlated with tumor immune infiltration. In this study, the expression of LINC02249 was found to be abnormally high in a variety of tumors, according to our findings. When compared with nontumor specimens, the level of expression of LINC02249 was shown to be significantly elevated in SKCM samples. GO and KEGG assays revealed LINC02249 may be involved in tumor progression. High expression of LINC02249 was associated with shorter overall survival and disease-specific survival of SKCM patients. More importantly, multivariate methods revealed that LINC02249 expression was an independent prognostic factor for SKCM cases. Using ssGSEA, we found that the expression of LINC02249 was negatively associated with different tumor-infiltrating immune cells, especially aDC, Treg, and macrophages. Overall, our findings suggested that LINC02249 can serve as a novel biomarker to predict the prognosis and immune infiltration in SKCM.

Treatment of Metastatic Melanoma at First Diagnosis: Review of the Literature

Metastatic melanoma (MM) is a pathological entity with a very poor prognosis that, until a few decades ago, had a low response rate to systemic treatments. Fortunately, in the last few years, new therapies for metastatic melanoma have emerged. Currently, targeted therapy and immunotherapy are the mainstays of the therapeutic arsenal available for patients with unresectable or metastatic melanoma. However, both clinical evolution and drug efficacy in melanoma patients are very different depending on the stage at which it is diagnosed. In fact, the aggressiveness of melanoma is different depending on whether it debuts directly as metastatic disease or if what occurs is a relapse after a first diagnosis at an early stage, although the biological determinants are largely unknown. Another key aspect in the clinical management of metastatic melanoma at first diagnosis strives in the different prognosis of melanoma of unknown primary (MUP) compared to melanoma of known primary (MPK). Understanding the mechanisms behind this, and the repercussion of implementing targeted and immune therapies in this specific form is crucial for designing diagnosis and treatment decision algorithms that optimize the current strategies. In this review article, we recapitulate the information available thus far regarding the epidemiology and response to immunotherapy treatments or targeted therapy in patients diagnosed with metastatic melanoma as a first diagnosis, with especial emphasis on the emerging specific information of the subpopulation formed by MUP patients.

Hypothesised cutaneous sites of origin of stage III melanomas with unknown primary: A multicentre study

Based on molecular evidence that melanomas with unknown primary (MUPs) arise from the skin, we hypothesised that sites of MUPs are disproportionately on trunk and lower limbs, sites that are not readily visible to patients and clinicians. We tested this hypothesis by inferring the anatomic site of origin of MUPs from the corresponding known cutaneous sites of melanoma patients with known primary tumours (MKPs). We analysed data from three separate cohorts of patients from Brisbane, Australia (n = 236); Manchester, UK (n = 51) and Padova, Italy (n = 33), respectively, who first presented with stage III melanoma with lymph node metastases. We matched two MKP patients to each MUP patient based on lymph node dissection (LND) site, age and sex, and imputed cutaneous sites of origin of MUPs from their two matched MKPs for study countries, giving two possible sites for each MUP per centre. Overall, results showed that MUP patients were predominantly male, and trunk was the most likely origin, comprising around a third to a half of MUPs across the three cohorts. The remaining MUP inferred sites varied by country. In the Australian cohort, the legs accounted for a third of imputed sites of MUPs, while in the UK and Italian cohorts, the most frequent site was the arms followed by the legs. Our findings suggest the need for regular and thorough skin examination on trunk and limbs, especially in males, to improve early detection of cutaneous melanoma and reduce the risk of metastatic disease at the time of presentation.

Malignant biliary obstruction due to metastatic non-hepato-pancreato-biliary cancer

Malignant biliary obstruction generally results from primary malignancies of the pancreatic head, bile duct, gallbladder, liver, and ampulla of Vater. Metastatic lesions from other primaries to these organs or nearby lymph nodes are rarer causes of biliary obstruction. The most common primaries include renal cancer, lung cancer, gastric cancer, colorectal cancer, breast cancer, lymphoma, and melanoma. They may be difficult to differentiate from primary hepato-pancreato-biliary cancer based on imaging studies, or even on biopsy. There is also no consensus on the optimal method of treatment, including the feasibility and effectiveness of endoscopic intervention or surgery. A thorough review of the literature on pancreato-biliary metastases and malignant biliary obstruction due to metastatic non-hepato-pancreato-biliary cancer is presented. The diagnostic modality and clinical characteristics may differ significantly depending on the type of primary cancer. Different primaries also cause malignant biliary obstruction in different ways, including direct invasion, pancreatic or biliary metastasis, hilar lymph node metastasis, liver metastasis, and peritoneal carcinomatosis. Metastasectomy may hold promise for some types of pancreato-biliary metastases. This review aims to elucidate the current knowledge in this area, which has received sparse attention in the past. The aging population, advances in diagnostic imaging, and improved treatment options may lead to an increase in these rare occurrences going forward.

A Case of Metastatic CNS Melanoma of Unknown Primary Presenting with Seizures

Seizures are a common occurrence. The goal of evaluating a seizure is to identify the etiology and to determine the likelihood of recurrence as well as guide management. We present a unique presentation of a 47-year-old female that presented with late onset seizures admitted due to status epilepticus. Brain magnetic resonance indicated diffuse supratentorial hemorrhagic lesions. Neurological workup including brain vessel imaging, CT chest, abdomen, and pelvis as well as CSF and serological workup for vasculitis failed to demonstrate the cause of her brain lesions. Ultimately, a brain biopsy showed metastatic melanoma of unknown primary origin.

Cytologic diagnosis of metastatic melanoma by FNA: A practical review

Malignant melanoma (MM) is a highly aggressive neoplasm with a growing worldwide incidence. It is not uncommon that the disease is already metastatic at the time of the first diagnosis. Regional lymph nodes and skin are the first and most common metastatic sites, followed by distant visceral sites (lungs, liver, and central nervous system) and bone. In this clinical setting, fine-needle aspiration (FNA) often represents the first diagnostic approach. FNA is a useful tool to obtain a rapid and accurate diagnosis, in conjunction with ancillary techniques and molecular analysis, as recommended by recent guidelines. The aim of this review was to describe the cytomorphology, immunocytochemical tools, and molecular tools used for the diagnosis of MM metastases on FNA.

Seborrheic keratosis-like melanoma: a diagnostic challenge

This article summarizes the main epidemiologic and diagnostic features of seborrheic keratosis-like (SK-like) melanoma. We performed a review of the current literature. The real and current incidence and prevalence of SK-like melanoma are unknown. Many lesions are misdiagnosed and not excised with histopathologic confirmation, or excised without an appropriate surgical approach due to a benign clinical and dermoscopic appearance. SK-like melanoma presents both melanoma and SK features. SK-like melanoma and SK are often clinically indistinguishable even for experienced dermatologists. Clinically, it develops as a black-dark brown or light slightly elevated, papule, nodule or plaque with rapid growth and a regular or irregular shape. SK-like melanoma presents melanocytic and nonmelanocytic dermoscopic features. Irregular dark-brown dots/globules, a blue-grayish veil, streaks, irregular pigmentation or network and brown lines point to a melanoma diagnosis. Among the nonmelanocytic features, milia-like cysts and comedo-like openings have been highlighted. The association of polarized and nonpolarized dermoscopic techniques is more accurate for studying the dermoscopic features of SK-like melanoma. If the dermoscopic features are unclear, further investigations with reflectance confocal microscopy (RCM) or biopsy with histologic examination are essential. SK-like melanoma is a dermatologic challenge. Careful clinical and dermoscopic evaluation favor a correct diagnosis. In unclear cases, it is important to perform a biopsy with histologic examination to confirm the correct diagnosis.

Thoracic metastasis of malignant melanoma of unknown primary: A case report and literature review

INTRODUCTION

Metastatic melanoma of unknown primary (MUP) is an unusual entity found in distant sites without evident skin lesion. We report a case of 45-year-old woman who underwent monobloc resection of a metastatic thoracic malignant melanoma of unknown primary, and who is currently under immunotherapy without local or distant recurrence during a follow-up of 18 months. We demonstrate through this case that R0 resection of an MUP associated with immunotherapy improves the prognosis and survival in these patients.

CASE REPORT

This is a 45-year-old woman who underwent monobloc resection of a mass carrying the anterior arch of the second left rib associated with a wedge resection of a nodule at the left upper lobe. Histology confirmed that it was a malignant melanoma. Her history was negative for melanocytic lesions, physical examination and imaging had failed to identify a primary lesion. The patient is currently under nivolumab for Stage IV melanoma and does not present any complications or recurrence during the long term follow up.

DISCUSSION

Metastatic melanoma of unknown primary (MUP) is a melanocytic lesion in distant sites in the absence of apparent skin involvement and is rare, accounting for 3, 2% of all incident melanomas as well as being yet poorly understood in terms of pathogenesis (Bae et al., 2015) [1]. MUP is clinically understudied, investigators to date have reported largely on the use of localized treatment for MUP (surgery or radiotherapy), while the efficacy of systemic therapy in MUP patients remains unexplored. Clinical trials of immunotherapy and targeted therapy in patients with advanced cutaneous melanoma have not explicitly reported response rates specific to MUP patient subgroups due to its low incidence and lack of annotation. MUP's response to these now FDA-approved therapies could add to the discussion of MUP's elusive biological characteristics, as well as aid in making clinical recommendations (Utter et al., 2017).

CONCLUSION

Metastatic MUP is an extremely rare entity which is still poorly understood, few cases are described in the literature, its treatment remains controversial and there are no specific treatment recommendations for patients with MUP. Several authors recommend local treatment when possible and tend to apply similar strategies for patients with paired stage primary known melanoma (PKM).

Biomarkers of Targeted Therapy and Immuno-Oncology in Cancers Metastatic to the Breast

The breast is a rare site for metastases, and their molecular characteristics have not been studied yet. Intrinsic molecular genetics, cancer characteristics, and breast tissue immune responses in diverse metastases to the breast have not been previously studied. We identified 64 patients with cancers metastatic to the breast: 51 carcinomas and 13 melanomas. Programmed death ligand 1 (PD-L1), steroid receptors, and HER2/neu expressions were evaluated using immunohistochemistry. Gene sequencing, copy number alterations, microsatellite instability, and tumor mutational burden were performed using next-generation sequencing platforms. The 3 most common primary sites for metastatic carcinomas were lung (37%), ovary (29%), and fallopian tubes/peritoneum (14%). TP53 mutations were commonly (50%) observed among the carcinoma cases, while other mutations were characteristic for the primary cancers (VHL in renal, BRCA1 in the fallopian tube, and BRAF in melanomas). High tumor mutational burden was detected in 5/14 carcinomas and 3/7 melanomas. Tumor cell PD-L1 expression was detected in 6 carcinomas, but not in any of the melanomas, whereas immune cells' expression of PD-L1 was seen in 17 carcinomas and 6 melanomas. Estrogen receptor status was positive in 13/49 carcinomas including 12 adenocarcinomas originating from the ovary and fallopian tube or peritoneum and 1 duodenal neuroendocrine carcinoma. No carcinoma was HER2/neu positive. Intrinsic genetic characteristics of the metastases to the breast followed the pattern commonly seen in primary tumors. Biomarkers of potential benefit to immune checkpoint inhibition therapy were limited to PD-L1-positive non-small cell lung cancer. No common characteristics of the heterogeneous group of tumor metastases to this organ were identified.

Outcomes after retreatment with MAPK inhibitors and immune checkpoint inhibitors in melanoma patients

Background: When patients with advanced melanoma progress after MAPK inhibitor (MAPKI) and immune checkpoint inhibitor (ICI) treatment, they can either undergo chemotherapy or rechallenge with previously used treatments. Methods: The outcomes of 48 patients retreated with MAPKIs and 50 patients retreated with ICIs following progression were retrospectively analyzed. Results: Upon retreatment with MAPKIs, the disease control rate was 60%. Univariate analysis of possible risk factors associated with short progression-free survival upon MAPKI treatment showed elevated lactate dehydrogenase to be associated with decreased progression-free survival. Disease control rate after ICI retreatment was 24%. Melanoma of unknown primary was associated with prolonged progression-free survival upon ICI retreatment. Conclusion: Retreatment with MAPKIs or ICIs is a feasible option for patients with advanced melanoma.

Primary malignant melanoma of the esophagogastric junction: A case report

RATIONALE

Most gastrointestinal melanomas are metastatic from an oculocutaneous primary lesion; however, primary gastrointestinal melanomas have been found in all levels of the gastrointestinal tract. We present the case of Primary malignant melanoma of the esophagus and discuss the diagnostic methods, differentiation from metastatic lesions and treatment options.

PATIENT CONCERNS

A 78-year-old male patient presented with fresh blood vomiting and tarry stools for 1 day.

DIAGNOSES

Esophagogastroduodenoscopy of this patient revealed a tumor ∼4 cm in size at the cardia side of the esophagogastric junction with dark-red and gray pigmentation. Immunohistochemical stains of the biopsy specimens were positive for S-100 and HMB-45, which are specific markers of melanoma.

INTERVENTIONS

Laparotomy with proximal gastrectomy was performed by the surgeon. Histological examination of the surgical specimen revealed the tumor arose from the distal esophagus with invasion of the proximal stomach. Primary malignant melanoma of the esophagus was diagnosed after a full skin and ophthalmic examination and positron emission tomography, which revealed no lesions elsewhere in the body.

OUTCOMES

No tumor recurrence was noted at the 1-year follow-up.

LESSONS

Primary malignant melanoma of the esophagus is an extremely rare but highly aggressive tumor. The special pattern of pigmentation should be recognized while performing endoscopy. Early detection and radical resection of the tumor are critical to ensure favorable outcomes.

Melanoma With an Unknown Primary in an Asymptomatic Elderly Male With Unilateral Lymphadenopathy

Melanoma with an unknown primary (MUP) is an uncommon metastatic melanoma without an obvious primary site. MUP has a higher prevalence in men in their fifth decade of life. The pathogenesis of MUP is still unknown but several hypotheses have been proposed including the predominant regression theory, occult cutaneous, or visceral location, or by the presence of ectopic melanocytes. Proper physical examination, imaging, and histopathological review are needed to diagnose MUP. Patients with MUP must be aggressively treated and monitored for recurrence. We present a case of MUP occurring in an asymptomatic 61-year-old male with axillary lymphadenopathy. We hope to raise awareness that melanoma of unknown primary can present in lymph nodes without external structural changes.

Comparative genomic characterization of melanoma of known and unknown primary

BACKGROUND

This study aims to genomically characterize melanoma of unknown primary (MUP) in comparison to melanomas of cutaneous primary (MCP).

METHODS

Eligible cases were collected from the MSK-IMPACT™ Clinical Sequencing Cohort published in the cBioPortal database. Genomic analysis was performed using a hybridization-capture-based next-generation sequencing assay designed to detect mutations, small insertions and deletions, copy number alterations, and genomic rearrangements.

RESULTS

Among 462 patients of whom 18.4% had MUP, brain metastasis was more common among patients with MUP (23% vs 7.1%). The differences in genomic profiling between MCP and MUP did not reach statistical significance. The 187 MCP and 44 MUP patients treated with immune checkpoint inhibitors had a median overall survival of 49 and 44 months, respectively (p = 0.705).

CONCLUSIONS

The differences in somatic mutation patterns and survival outcomes were not statistically significant. These findings may allude to similar carcinogenic processes but should be considered exploratory and interpreted with caution.

Melanoma brain metastases in Ireland: surgical and systemic considerations

BACKGROUND

Cerebral metastases is a common complication in patients with melanoma. There is a paucity of information in the Republic of Ireland regarding the factors associated with melanoma brain metastases (MBM).

METHODS

Patients diagnosed with melanoma brain metastases in Ireland were retrospectively identified in Beaumont Hospital between 1999 and 2018. Patient demographics; age at diagnosis of primary melanoma, age at detection of MBM, year of detection of MBM, anatomical location of primary melanoma, BRAF mutation analysis and the number of metastases were investigated. Follow-up data were also derived, including overall survival.

RESULTS

There has being a 158% increase in the incidence of primary melanoma from 1999 compared to 2016. Over the same time period 128 patients with melanoma brain metastases were diagnosed. There was a significant male predominance (n = 77/128; 60%; p < 0.0001). BRAF mutation and leptomeningeal disease were independent prognostic factors in our cohort with a median survival 8 months and 0.5 months, respectively.

CONCLUSIONS

Male predominance, leptomeningeal disease and BRAF mutation represent important considerations in this population group. The results of this study add to our knowledge concerning outcomes in melanoma brain metastases and may be useful in clinical planning and future treatments.

Combined immune checkpoint inhibitors of CTLA4 and PD-1 for hepatic melanoma of unknown primary origin: A case report

BACKGROUND

Melanoma is uncommonly found in lymph nodes, subcutaneous tissue, or visceral organs without a primary lesion, where it is identified as metastatic melanoma with unknown primary (MUP). Hepatic MUP is extremely rare and has a poor prognosis. There is limited information on its pathogenesis, clinical and imaging features, and pathological findings. There are no guidelines for the use of immune checkpoint inhibitors (ICIs) in hepatic MUP, and the treatment outcome has rarely been reported.

CASE SUMMARY

A 42-year-old woman presented to our hospital with hepatic tumors found incidentally during a routine check-up. Contrast-enhanced abdominal com-puterized tomography showed multiple mass lesions in the liver. Pathological results revealed melanoma, which was confirmed by immunohistochemical staining for HMB-45(+), Melan-A(+), S-100(+), and SOX10(+). There was no evidence of primary cutaneous, ocular, gastrointestinal, or anal lesion on a comprehensive examination. The patient was diagnosed with hepatic MUP. She received combined antibodies against cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4, ipilimumab) and programmed death protein-1 (PD-1, nivolumab). She died of hepatic failure 9 mo after hepatic MUP was diagnosed. This the first case of hepatic MUP treated with combined ipilimumab and nivolumab, who showed better outcome than previous cases.

CONCLUSION

Combined ICIs of PD-1 and CTLA-4 may be considered as the first-line therapy for patients with hepatic MUP.

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) 8th 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.

Multidisciplinary Care for Melanoma of Unknown Primary: Experience in the Era of Molecular Profiling

BACKGROUND

Melanoma of unknown primary (MUP) accounts for approximately 3% of melanoma diagnoses. This study sought to evaluate treatment and outcomes for a modern MUP cohort.

METHODS

A retrospective review of MUP was performed at a tertiary referral cancer center.

RESULTS

Of 815 melanoma patients, 67 (8.2%) had MUP. Men were more likely to have MUP than women (67% vs. 55%; p = 0.04). The most common sites of MUP were lymph nodes (28%), visceral solid organs (25%), brain (16%), and skin/subcutaneous tissues (10%). Of the patients who underwent tumor genomic profiling, 52% harbored pathogenic BRAF mutations. Of the 24 patients who underwent multi-gene panel testing, all had pathogenic mutations and 21 (88%) had mutations in addition to or exclusive of BRAF, including 11 patients (46%) with telomerase reverse transcriptase promoter mutations. Checkpoint inhibitors (39%) and BRAF-MEK inhibitors (7%) were the most common first-line treatments. Upfront surgical resection was used for 25% of the MUP patients, and 12 of these resections were for curative intent. During a median follow-up period of 22.1 months, the median overall survival (OS) was not met for the patients with MUP isolated to lymph nodes. At 56.8 months, 75% of these patients were alive. The median OS was 37.4 months for skin/soft tissue MUP, 33.3 months for single solid organ viscera MUP, and 29.8 months for metastatic brain MUP.

CONCLUSION

Multigene panel testing identified pathogenic mutations in all tested MUP patients and frequently identified targets outside BRAF. Despite advanced stage, aggressive multimodal therapy for MUP can be associated with 5-year OS and should be pursued for appropriate candidates.

Paraneoplastic Cerebellar Degeneration Secondary to BRAF Mutant Melanoma Metastasis from an Occult Primary Cancer

Melanoma metastasis from an unknown primary cancer has an incidence of 3.2% among melanoma patients. Furthermore, paraneoplastic neurological syndromes (PNS) are rare, occurring in 1-3% of patients with malignancies. Paraneoplastic cerebellar degeneration (PCD) is one of the classic PNS and is characterized by acute or subacute onset of ataxia and/or presence of onconeural antibodies. A 61-year-old male with ataxia, vertigo, and headache later developed dysarthria, multidirectional nystagmus, hyperactive delirium, auditory hallucinations, psychomotor agitation, and myoclonus. Toxicological, metabolic, infectious, and autoimmune etiologies were assessed and reported negative. An osteolytic lesion was observed in the right iliac crest via computed tomography (CT). A positron emission tomography-CT reported increased fluorodeoxyglucose uptake of a right iliac and right inguinal ganglion. After biopsy of the right inguinal ganglion, a BRAF mutation-positive melanoma metastasis from an occult primary cancer was diagnosed. Dermatologic, ophthalmologic, and endoscopic gastrointestinal assessment did not reveal a primary malignant melanoma. The patient's movement disorders and neuropsychiatric symptoms improved with quetiapine, prednisone, azathioprine, and cyclophosphamide. Oncological management was conducted with MAPK pathway inhibitors (i.e., dabrafenib and trametinib). Movement disorders associated with neuropsychiatric symptoms are complex to diagnose. PNS are rare and often associated with antibodies against neural antigens expressed by the tumor. The case presented above describes a patient with a BRAF-positive malignant melanoma metastasis from an occult primary associated with PCD - to the best of our knowledge, the first reported in the literature.

Large Necrotic Mass in the Small Bowel

Melanoma of unknown primary (MUP) is a melanoma found in sites other than the skin, mucosa, or eye. It is most commonly present in lymph nodes and least frequently in visceral organs. Diagnosis is difficult given its internal presentation and is often late stage with poor prognosis. We report an 89-year-old man who presented with weakness, a 27-kg weight loss, and gastrointestinal bleeding. He was found to have a large necrotic mass in the small bowel consistent with melanoma. Although he had extensive skin, anogenital, and ocular examinations, no cutaneous lesion was identified, therefore leading to a diagnosis of MUP.

Adrenal Gland and Gastric Malignant Melanoma without Evidence of Skin Lesion Treated with the Oncolytic Virus Rigvir

Adrenal gland melanoma is an extremely rare diagnosis with less than 20 cases reported. The criteria for diagnosing adrenal gland melanoma include involvement of only one adrenal gland, presence of melanin pigment in the histological examination of the tumor tissue, no primary melanoma tumor in any other organ, and no history of resection of pigmented lesions. However, it is complicated to rule out melanoma of unknown primary origin. Here we report a female patient who at the age of 75 years was admitted to hospital due to suspicion of adrenal and gastric tumor. The largest tumor was found in the adrenal gland, thus leading to the diagnosis of primary adrenal gland melanoma presenting metastases in the stomach. The melanoma was BRAF wild type. Due to the rarity of this disease, there is no standard treatment. After two subsequent surgeries, treatment with the ECHO-7 oncolytic virus Rigvir was started. The patient has received oncolytic virotherapy for 5 years and 1 month and has been stable since then with good tolerability. The therapy is still ongoing. Adrenal gland melanoma is an extremely rare diagnosis and therefore it is important to discuss the diagnostic criteria and possible treatments.

Melanoma of unknown primary in the pancreas: should it be considered primary?

Background

Malignant melanoma is characterized as highly malignant due to its rapid growth and early metastasis. Metastatic melanoma from occult primary is rare. Melanoma of unknown primary in pancreas are even rear. But it is a biologically ill-defined and clinically understudied concept.

Case presentation

In this report, a 43-year-old man was diagnosed with pancreatic carcinoma. Extended total pancreatectomy together with portal vein reconstruction and extensive lymphadenectomy were performed in our hospital. The patient was diagnosed with pancreatic malignant melanoma after pathological examination. He was still alive 20 months after the operation without any evidence of recurrence.

Conclusion

The described case highlights the possibility of primary pancreatic malignant melanoma and the treatment strategies of this rare carcinoma.

Clinicopathologic characteristics of malignant non-hematopoietic tumors first presented as an axillary mass with emphasis on occult breast carcinoma

BACKGROUND

Non-hematopoietic malignancies first presented as an axillary mass constitute a unique clinical presentation. We investigated the incidence of various types of malignancies and aimed to define clinicopathologic variables that may assist in the diagnosis, with focus on occult breast carcinoma (OBC).

DESIGN

We reviewed the pathology reports of cases with non-hematopoietic malignancies of the axillary region in our institution between 2000 and 2016. We included patients who presented first with axillary mass and with the absence of a known primary. We recorded patients' age and gender, tumor characteristics including size, histologic type, number of positive lymph nodes, and the clinical management. Then we focused on BC which were divided into OBC or primary BC (PBC).

RESULTS

There were 100 cases that met our criteria (28 melanoma, 7 sarcoma and 65 carcinoma). For carcinoma cases, there were 42 BC (19 OBC, 17 PBC, and 6 possible OBC), 17 non-BC, and 6 carcinoma of unknown primary (CUP). Tumors found incidentally were more likely to be of breast primary (p = 0.01). Larger tumor size (in mm) favored melanoma or sarcoma over BC, non-BC carcinoma or CUP with median and range 61 (15, 180), 60 (23, 80), 30 (15, 75), 31 (17, 90), 26 (20, 55), respectively (p < 0.001). There were no differences in the histopathologic findings or clinical presentation.

CONCLUSIONS

More than half of the patients with axillary malignancy have a tumor of non-breast origin. Therefore, clinical and pathologic studies are warranted to identify the primary site.

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.

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

Melanoma of unknown primary (MUP) may have a different biology to melanoma of known primary, but clinical trials of novel therapies (e.g., immune checkpoint or BRAF/MEK inhibitors) have not reported the outcomes in this population. We therefore evaluated the overall survival (OS) among patients with MUP in the era of novel therapy. Data for stage III or IV MUP were extracted from a nationwide database for the period 2003–2016, with classification based on the eighth edition of the American Joint Committee on Cancer criteria. The population was divided into pre‐ (2003–2010) and post‐ (2011–2016) novel therapy eras. Also, OS in the post‐novel era was compared between patients with stage IV MUP by whether they received novel therapy. In total, 2028 of 65,110 patients (3.1%) were diagnosed with MUP. Metastatic sites were known in 1919 of 2028 patients, and most had stage IV disease (53.8%). For patients with stage III MUP, the 5‐year OS rates were 48.5% and 50.2% in the pre‐ and post‐novel eras, respectively (p = 0.948). For those with stage IV MUP, the median OS durations were unchanged in the pre‐novel era and post‐novel era when novel therapy was not used (both 4 months); however, OS improved to 11 months when novel therapy was used in the post‐novel era (p < 0.001). In conclusion, more than half of the patients with MUP are diagnosed with stage IV and the introduction of novel therapy appears to have significantly improved the OS of these patients.

What's new?

Melanoma of unknown primary (MUP) site may have a different biology to melanoma of known primary, but clinical trials of novel therapies (e.g., immune checkpoint or BRAF/MEK inhibitors) have not reported the outcomes in this population. Knowledge about outcomes could however aid clinical management of patients with MUP. In this nationwide study from 2003 to 2016, the authors show that the introduction of novel therapy has significantly improved the overall survival for patients with stage IV melanoma of unknown primary, who represented more than half of the patients diagnosed with MUP in the Netherlands.

Paraneoplastic opsoclonus-myoclonus syndrome secondary to melanoma metastasis form occult primary cancer

Introduction

Opsoclonus-myoclonus syndrome (OMS) is an inflammatory neurological disorder, often requiring a prompt medical evaluation. Among the diverse etiologies associated with OMS are autoimmune, infectious, paraneoplastic, and systemic diseases, and drug intoxication.

Clinical Summary

The case of a 36-year-old female with a disabling holocranial headache, sudden loss of consciousness, aggressive behavior, vertigo, and a personal history of somatoform disorder and major depression is presented here. After hospital admission, the patient developed sudden stereotyped movements in all four extremities and oculogyric crises compatible with OMS. Cerebrospinal fluid analysis, viral and autoimmune assays, as well as blood, urine, and bronchial secretion cultures, drug metabolite urinalysis, and tumor markers were all negative. Furthermore, brain computed tomography (CT) and brain magnetic resonance imaging, along with thoraco-abdominopelvic CT and electroencephalography, were also all negative. The patient suffered type one respiratory insufficiency after 72 h of hospitalization, requiring an endotracheal tube. After 13 days the patient suffered cardiac arrest. Necropsy was performed reporting lymph nodes with a poorly differentiated malignant neoplastic lesion, HMB-45, melan-A, vimentin, and S-100 positive, compatible with melanoma metastasis from an occult primary cancer.

Discussion

While the incidence of melanoma of unknown primary is between 2.6 and 3.2%, with a median overall survival ranging between 24 and 127 months, when melanoma patients develop OMS their survival is markedly decreased. Although only 5 cases of paraneoplastic OMS secondary to melanoma have been reported in the literature, all had a poor prognosis, dying within 8 months of OMS onset.

Current management of regional lymph nodes in patients with melanoma

The publication of recent randomized trials has prompted a significant shift in both our understanding and the management of patients with melanoma. Here, the current management of the regional lymph nodes in patients with melanoma is discussed. This review focuses on selection for sentinel lymph node biopsy, management of the positive sentinel node, management of the clinically positive node, and the controversy over the therapeutic value of early nodal intervention.

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.

Molecular Diagnostics in Clinical Oncology

There are multiple applications of molecular tests in clinical oncology. Mutation analysis is now routinely utilized for the diagnosis of hereditary cancer syndromes. Healthy carriers of cancer-predisposing mutations benefit from tight medical surveillance and various preventive interventions. Cancers caused by germ-line mutations often require significant modification of the treatment strategy. Personalized selection of cancer drugs based on the presence of actionable mutations has become an integral part of cancer therapy. Molecular tests underlie the administration of EGFR, BRAF, ALK, ROS1, PARP inhibitors as well as the use of some other cytotoxic and targeted drugs. Tumors almost always shed their fragments (single cells or their clusters, DNA, RNA, proteins) into various body fluids. So-called liquid biopsy, i.e., the analysis of circulating DNA or some other tumor-derived molecules, holds a great promise for non-invasive monitoring of cancer disease, analysis of drug-sensitizing mutations and early cancer detection. Some tumor- or tissue-specific mutations and expression markers can be efficiently utilized for the diagnosis of cancers of unknown primary origin (CUPs). Systematic cataloging of tumor molecular portraits is likely to uncover a multitude of novel medically relevant DNA- and RNA-based markers.

Characteristics of melanoma in Japan: a nationwide registry analysis 2011-2013

The distribution and incidence of melanoma vary among different races and ethnic groups. This study aimed to investigate the characteristics of cutaneous melanoma, mucosal melanoma, uveal melanoma, and melanoma of unknown primary (MUP) origin in a Japanese population. We studied these four types of melanoma in patients registered in Hospital Based Cancer Registries in Japan from 2011 to 2013. A total of 5566 patients with melanoma were identified. The distribution of sex, age, primary site, and clinical stage was analyzed. The number of patients, proportion in comparison with all melanoma cases, and crude incidence rate per 100 000 person-year of each melanoma type were 4481, 80.5%, and 1.24 in invasive cutaneous; 821, 14.8%, and 0.32 in mucosal; 163, 2.9%, and 0.064 in uveal; and 101, 1.8%, and 0.039 in MUP origin, respectively. Including the patients with in-situ cutaneous melanoma and stage unknown cutaneous melanoma, the crude incidence rate of cutaneous melanoma increased at 1.75. Almost half of the cutaneous melanomas were located in the lower limb. Cutaneous melanoma was the most common, but less frequent than that in western countries. Mucosal melanoma was quite rare, but its proportion and crude incidence rate were higher than those in western countries. Uveal melanoma was particularly rare, and its crude incidence rate was lower than that in western countries. MUP origin was also particularly rare, but it had almost the same incidence rate as that in other countries. Melanoma in Japan was heterogeneous among the four melanoma types and shares some attributes with that in western countries.

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.

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.