Abstract
RATIONALE: Duodenal malignant melanoma is rare, and its early clinical symptoms are insidious, making it difficult to diagnose in its early stages. Combined with previous literature, We explored the clinicopathological characteristics and v-raf murine sarcoma viral oncogene homolog B1 mutations in primary and metastatic duodenal malignant melanoma, in order to provide some experience on its differential diagnosis and treatment. PATIENT CONCERNS: The 2 patients (a 63-year-old female [Patient 1] and a 54-year-old male [Patient 2]) experienced pain and discomfort in their upper abdomen. Additionally, one of them had a history of skin malignant melanoma. DIAGNOSES: Patient 1 was diagnosed with primary duodenal malignant melanoma; and Patient 2 was diagnosed with metastatic duodenal malignant melanoma. INTERVENTIONS: Patient 1 underwent pancreaticoduodenectomy; and patient 2 underwent complete surgical resection and lymph node dissection. OUTCOMES: After surgery, Patient 1 survived after 26 months follow-up, and Patient 2 died of systemic multi-organ circulatory failure after 1 month follow-up. LESSONS: Primary and metastatic cases should be diagnosed through previous medical history analysis and detailed physical and auxiliary examinations. This would enable a diagnosis based on characteristic histomorphology and immunohistochemical markers. An early diagnosis and surgical treatment can prolong patient survival and the molecular inspection of v-raf murine sarcoma viral oncogene homolog B1 mutations can guide follow-up treatment.