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

Melanoma of Unknown Primary With Metastasis to the Brain: A Case Report and Review of the Literature

We present the case of a 72-year-old male found to have melanoma of unknown primary (MUP) in the lung with brain metastasis. The patient has a history of prostate cancer with radical proctectomy in 1999, hypertension with right-sided heart failure, and bilateral cataracts treated operatively. He presented to their home hospital after an unwitnessed fall, with a history of left-sided weakness. He was found to have a parietal lobe mass and two lung masses, where he was transferred to our hospital for a higher level of care. Biopsy of the lung lesion revealed melanoma, and the patient did not have any skin or mucosal foci present to indicate a primary source. We present this case in conjunction with a review of the literature. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, our review resulted in 31 MUP case reports. Data was extracted on epidemiology, clinical presentations, diagnostics, treatment, and outcomes. The mean age was 57.5 with a male-to-female ratio of 1:1.3. The greatest instances of MUP occurred in prior smokers and patients with comorbidities, accounting for 17.95% of cases each. Thirty-one percent of patients presented with a growing palpable mass, 21% with gastrointestinal symptoms, and 21% with B-symptoms. Biopsy was the diagnostic standard, and the majority of patients also underwent biomarker studies. Treatment varied widely, and many patients underwent multiple phases. Outcomes ranged from death within several months to a disease-free period of three years. Our paper highlights the complexity and nuances of diagnosing MUP and primary malignant melanoma of the lung (PMML) and calls for further investigations to improve diagnostic and therapeutic approaches for rare presentations of melanoma. Despite limitations in sample size and data heterogeneity, this study highlights the diverse presentation and disease course of MUP, necessitating further studies to optimize patient outcomes.

Comments on and Illustrations of the EFSUMB CEUS Guidelines: Transabdominal and Endoscopic Ultrasound Features of Intrapancreatic Metastases and the Role of Multiparametric Imaging and EUS-Guided Sampling in Rare Pancreatic Tumors

A definite pathologic diagnosis of intrapancreatic metastasis is crucial for the management decision, i.e., curative or palliative surgery versus chemotherapy or conservative/palliative therapy. This review focuses on the appearance of intrapancreatic metastases on native and contrast-enhanced transabdominal ultrasound and endoscopic ultrasound. Differences and similarities in relation to the primary tumor, and the differential diagnosis from pancreatic carcinoma and neuroendocrine neoplasms are described. The frequency of intrapancreatic metastases in autopsy studies and surgical resection studies will be discussed. Further emphasis is placed on endoscopic ultrasound-guided sampling to confirm the diagnosis.

The role of resection for melanoma metastases to the pancreas

BACKGROUND

Among patients with distant metastatic melanoma, the site of metastases is the most significant predictor of survival and visceral-nonpulmonary metastases hold the highest risk of poor outcomes. However, studies demonstrate that a significant percentage of patients may be considered candidates for resection with improved survival over nonsurgical therapeutic modalities. We aimed at analyzing the results of resection in patients with melanoma metastasis to the pancreas by assessing the available evidence.

METHODS

The PubMed/MEDLINE, WoS, and Embase electronic databases were systematically searched for articles reporting on the surgical treatment of pancreatic metastases from melanoma. Relevant data from included studies were assessed and analyzed. Overall survival was the primary endpoint of interest. Surgical details and oncological outcomes were also appraised.

RESULTS

A total of 109 patients treated surgically for pancreatic metastases were included across 72 articles and considered for data extraction. Overall, patients had a mean age of 51.8 years at diagnosis of pancreatic disease. The cumulative survival was 71%, 38%, and 26% at 1, 3 and 5 years after pancreatectomy, with an estimated median survival of 24 months. Incomplete resection and concomitant extrapancreatic metastasis were the only factors which significantly affected survival. Patients in whom the pancreas was the only metastatic site who received curative resection exhibited significantly longer survival, with a 1-year, 3-year, and 5-year survival rates of 76%, 43%, and 41%, respectively.

CONCLUSION

Within the limitations of a review of non-randomized reports, curative surgical resection confers a survival benefit in carefully selected patients with pancreatic dissemination of melanoma.

Contrast-enhanced ultrasound of pancreatic melanoma: A case report and literature review

Melanoma is a malignant tumor that originates from melanocytes, most of which are of cutaneous origin. Most melanomas identified in the pancreas are metastatic, and primary pancreatic melanoma is extremely rare and has rarely been discussed. The correct preoperative diagnosis of pancreatic metastatic melanoma, especially primary melanoma, is challenging. Herein, we report a 43-year-old man who presented to our hospital due to unexplained left abdominal distension and pain. Abdominal ultrasound examination demonstrated multiple space-occupying lesions of the pancreas, and hypoechoic masses partially filled the splenic vein behind the pancreatic body. In the contrast-enhanced ultrasound (CEUS), all of these lesions showed iso-enhancement to slight hypo-enhancement in the arterial phase and hypo-enhancement in the venous phase. Masses in the splenic vein also showed hypo-enhancement. Imaging features suggested that the pancreatic lesions were malignant tumors. The tumor markers carcinoembryonic antigen, carbohydrate antigen 125 and carbohydrate antigen 19-9 were within normal limits. Based on clinical symptoms, imaging findings and incidence of pancreatic tumors, the patient’s clinical diagnosis was pancreatic carcinoma. Surgery was performed for the patient, while postoperative pathology confirmed malignant melanoma of the pancreas. Therefore, it is significant to identify the clinical and imaging manifestations of pancreatic melanoma in order to better manage the disease. Herein, we reported this case and reviewed the literature from 2000 to 2021 on the clinical and imaging features of 26 patients with pancreatic melanoma. It may improve clinicians’ awareness of the clinical and imaging performance of pancreatic melanoma, resulting in improved diagnosis, differential diagnosis, treatment, and outcomes.

Intra-Abdominal Malignant Melanoma: Challenging Aspects of Epidemiology, Clinical and Paraclinical Diagnosis and Optimal Treatment—A Literature Review

According to European consensus-based interdisciplinary guidelines for melanoma, cutaneous melanoma (CM) is the most deadly form of dermatological malignancy, accounting for 90% of the deaths of skin cancer patients. In addition to cutaneous melanoma, mucosal melanoma occurs in four major anatomical sites, including the upper respiratory tract, the conjunctiva, the anorectal region, and the urogenital area. As this cancer type metastasizes, a classification used in the current medical literature is the distinction between secondary lesions and primary malignant melanoma of the abdominal cavity. Given that malignant melanoma is the most common cancer that spreads to the gastrointestinal tract, different imaging modalities compete to diagnose the phenomenon correctly and to measure its extension. Treatment is primarily surgery-based, supported by immunotherapy, and prolongs survival, even when performed at stage IV illness. In the end, special forms of malignant melanoma are discussed, such as melanoma of the genito-urinary tract and amelanotic/achromic melanoma. The importance of this present literature review relies on yielding and grouping consistent and relevant, updated information on the many aspects and challenges that a clinician might encounter during the diagnosis and treatment of a patient with intra-abdominal melanoma.

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.