Epidemiology and outcomes of gastrointestinal mucosal melanomas: a national database analysis

Small bowel melanoma causing obstruction: A case report and a literature review

INTRODUCTION

Primary small bowel melanoma (PSBM) is a rare form of melanoma that originates from the intestinal mucosa. It is typically asymptomatic; however, it can present with non-specific symptoms, which pose challenges in accurately diagnosing the condition. In rare cases, it may manifest as small bowel obstruction, further adding challenges with diagnosis and management.

CASE PRESENTATION

A 57-year-old male presented to the hospital with complaints of chronic constipation, abdominal pain, and abdominal enlargement. Computed tomography (CT) scan revealed thickening of the jejunum wall, while endoscopy and biopsy revealed nothing. During surgery, surgeons identified and excised a jejunal mass. Subsequent pathological analysis confirmed the diagnosis of melanoma, and post-surgical examination failed to identify primary cutaneous melanoma.

DISCUSSION

PSBM is a rare and aggressive tumor often misdiagnosed due to non-specific symptoms and challenging imaging interpretations. Obstruction and intussusception are uncommon presentations. Surgical resection offers symptom control and improved prognosis, but achieving negative margins can be challenging. Early recognition and diagnosis are crucial for optimal management.

CONCLUSION

The lack of data in the literature presents challenges in identifying and selecting the optimal approach for managing PSBM. Physicians should increase their awareness of this specific type of tumor to facilitate early-stage diagnosis and provide appropriate care for patients.

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.

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.