Primary and metastatic melanoma of the GI tract: clinical presentation, endoscopic findings, and patient outcomes

Metastatic Melanoma to the Small Bowel and Colon: A Systematic Review of the Global Experience and Institutional Cohort Analysis Detailing a Rare Clinical Entity

INTRODUCTION

Cutaneous melanoma is among the most common solid tumors to metastasize to the gastrointestinal (GI) tract. Literature summarizing the clinical experience and features of this unique pathology is lacking.

METHODS

A systematic review of the available literature reporting clinically salient features of melanoma metastases to the small and large intestines was conducted. Additionally, we surveyed our institutional experience of surgically treated melanoma metastasis to the small bowel and colon. A descriptive analysis was performed. Kaplan-Meier curves with log-rank tests were used to analyze time-to-event intervals. Univariable and multivariable Cox logistic regression models were generated to identify predictors of survival.

RESULTS

Over 100 studies including 1153 patients were included. GI metastases predominantly affected males, were in the small bowel/jejunum, equally presented as solitary and multiple lesions, and were generally not the first site of distant metastatic disease. The median time from primary lesion diagnosis to GI metastasis was 48 months. Analysis of our institutional cohort suggested that survival in patients receiving complete GI-specific surgical resection and immune checkpoint inhibitors (ICIs) was prolonged compared to palliative resection and without ICI therapy. Positive prognostic factors for survival following GI metastasis included fewer GI metastatic lesions, complete resection, and longer duration between primary tumor diagnosis and GI metastasis.

CONCLUSIONS

GI metastases are a sign of advanced metastatic melanoma. Clinical suspicion of metastatic involvement in patients with a history of melanoma who develop any abdominal symptoms or anemia should remain high. Receipt of complete surgical resection and ICIs may prolong survival in disseminated melanoma.

Prognostic models based on lymph node density for primary gastrointestinal melanoma: a SEER population-based analysis

OBJECTIVE

This study aimed to construct prognostic models to predict the overall survival (OS) and cancer-specific survival (CSS) of patients with primary gastrointestinal melanoma (PGIM).

DESIGN

An observational and retrospective study.

SETTING

Data were obtained from the Surveillance, Epidemiology and End Results (SEER) programme database, encompassing a broad geographical and demographic spectrum of patients across the USA.

PARTICIPANTS

A total of 991 patients diagnosed with PGIM were included in this study.

METHODS

A total of 991 patients with PGIM were selected from the SEER database. They were further divided into a training cohort and a validation cohort. Independent prognostic factors were identified by Cox regression analysis. Two prognostic models were constructed based on the results of multivariable Cox regression analysis. The concordance index (C-index) and area under the time-dependent receiver operating characteristic curve (time-dependent AUC) were used to evaluate the discriminative ability. Calibration curves were plotted to evaluate the agreement between the probability as predicted by the models and the actual probability. Risk stratification was developed given the model.

RESULTS

By the multivariable Cox regression analysis, we identified four independent risk factors (age, stage, lymph node density and surgery) for OS, and three independent risk factors (stage, lymph node density and surgery) for CSS, which were used to construct prognostic models. C-index, time-dependent AUC, calibration curves and Kaplan-Meier curves of risk stratification indicated that these two models had good discriminative ability, predictive ability as well as clinical value.

CONCLUSIONS

The prognostic models of OS and CSS had satisfactory accuracy and were of clinical value in evaluating the prognosis of patients with PGIM.

Metastatic melanoma presenting with dyspepsia: a case report

The gastrointestinal tract is an uncommon site for metastasis. Gastrointestinal metastasis of melanoma is usually asymptomatic, often affects the small intestine (81.1%) and the colon (15.1%), and rarely affects the stomach. Our patient was a 40-year-old man presenting with gradually worsening dyspepsia of a few weeks’ duration. He did not mention other gastrointestinal symptoms, and he was not anemic. He had a history of auricular melanoma, which was resected. A black lesion with a diameter of approximately 20 mm was detected in the body of his stomach during upper gastrointestinal endoscopy. Biopsies were taken, and the diagnosis of metastatic melanoma was confirmed by immunohistochemistry (IHC). A gastrointestinal work-up, computed tomography (CT), and positron-emission tomography (PET) did not reveal additional lesions. The lesion in the stomach was resected, and a new course of chemotherapy was initiated. A lower threshold should be considered for gastrointestinal work-up in patients with melanoma.

Oral malignant melanoma with gastric metastasis and hemorrhage: A case report

BACKGROUND

Although the gastrointestinal tract is a relatively common site of melanoma metastases, reports of digestive tract hemorrhage caused by melanoma are very rare. The metastatic route is still unclear, though it is considered as implant metastasis in oral malignant melanoma.

CASE SUMMARY

We report the case of an 88-year-old man who was admitted to our hospital with hematemesis and melena. By endoscopic inspection, he was diagnosed with active hemorrhage caused by primary gastric cancer or gastric stromal tumor. Eventually, he underwent surgical resection treatment and was discharged. At the outpatient review 3 wk postoperatively, it was noted that an oral melanoma which had been overlooked preoperatively had enlarged several times and was eventually considered to be the primary focus of the gastrointestinal melanoma. The patient passed away at home after 1 mo.

CONCLUSION

In the present case, an oral cavity mass was found but not further identified, which caused misdiagnosis. The possibility of malignant melanoma should be considered when encountering a gastrointestinal mass, especially when combined with mucocutaneous melanoma. In patients who have pure cutaneous melanoma, attention should also be paid to their gastrointestinal symptoms, with regular gastrointestinal endoscopy or systemic examination performed.

Epidemiology and survival outcomes of primary gastrointestinal melanoma: a SEER-based population study

PURPOSE

Primary melanoma arising in the gastrointestinal (GI) tract is rare and poorly characterized. We sought to describe the epidemiology and survival outcomes of primary GI melanoma.

PATIENTS AND METHODS

GI melanoma cases were extracted from the Surveillance, Epidemiology, and End Results (SEER) database by tumor site and histology codes. We calculated age-adjusted incidence, and analyzed demographics, clinical characteristics, as well as overall survival (OS) and cancer-specific survival (CSS) of GI melanoma.

RESULTS

A total of 1080 histologically confirmed cases of primary GI melanoma were identified, with a median age of 71 years (IQR: 59-80). 49.9% of the cases originated from anus, 30.8% had distant disease at diagnosis, and 61.5% received cancer-directed surgery. The distribution of gender and age was varied in GI melanoma subtypes. The incidence of GI melanoma was 0.58 cases per million, and increased remarkably over age, especially in patients aged 60 years or older. The median OS and CSS of the whole cohort was 14 months (95% CI 12.7-15.3) and 22 months (95% CI 18.8-25.2), respectively. Anal melanoma patients had prolonged survival, while those with gastric melanoma had the poorest OS (18 and 4 months, respectively). Multivariate analysis showed that decreased survival was associated with age older than 80 years, gastric and esophageal origin, advanced-stage disease, lymph node metastasis, and without surgery of primary site.

CONCLUSION

Patients with primary GI melanoma trended to present with advanced-stage disease. Overall, GI melanoma had a poor prognosis, but the outcome differed according to the primary sites.