Primary malignant melanoma of the parotid gland (PGMM) is extremely rare, with a poor prognosis. Surgery is the main treatment option followed by adjuvant treatments such as radiotherapy, but which adjuvant treatment to be optimal is still controversial. In this case, a 63-year-old male PGMM patient was first misdiagnosed as a “myoepithelial tumor” and then treated with surgery, postoperative immunotherapy (sintilimab), chemotherapy, and radiotherapy successfully. The progression free survival was more than 19 months without signs of metastasis or recurrence to date. To our best knowledge, this is the first report of postoperative immunotherapy combined with chemotherapy and radiotherapy for PGMM. Our case indicated that combination therapy including surgery, adjuvant immunotherapy (sintilimab) combined with chemotherapy and radiotherapy may be a potential treatment option for PGMM, which needs further research.

Primary cardiac angiosarcoma (PCA) is a relatively rare and fatal disease with poor prognosis. It remains controversial whether its survival can be improved with additional treatment besides complete surgical excision. In this case,we presented a 52-year-old man with PCA in the right atrial who underwent a palliative resection, but suffered from metastases of the brain, lung and liver rapidly. He accepted multi-mode combination therapy including first-line chemotherapy, second-line anlotinib which was not only concurrent with brain radiotherapy but also concurrent with immunotherapy in the end. Although anlotinib combined with brain radiotherapy had a effectively control on the intracranial lesions, progression free survival was 5 months. But overall survival didn’t significantly prolonged, for he only survived for 12 months. In conclusion, the treatment for those metastatic PCA still needs further exploration.

Rationale: Multiple primary malignant tumors are rare and challenging to diagnose. Diffuse malignant peritoneal mesothelioma (DMPM) originate from the peritoneum, which lacks specific clinical manifestations and is difficult to diagnose, with a short survival about 10 to 13 months for inoperable ones. This is the first report of metachronous double primary malignant tumors in nasopharyngeal carcinoma and DMPM accompanied with paraneoplastic syndromes. Patient concerns: A 61-year-old man presented with abdominal discomfort with a history of nasopharyngeal carcinoma 5 years ago. Diagnoses: The diagnosis of DMPM was finally confirmed by laparoscopic mesenteric biopsies. Paraneoplastic syndromes including increased platelets were present when diagnosis, followed by increased neutrophils after disease progression. Interventions: Due to intolerable for surgery, he was treated with pemetrexed combined with nivolumab, intraperitoneal infusion of nivolumab, radiotherapy, anlotinib and maintenance treatment of nivolumab. Outcomes: Progression-free survival in first line is 12 months, overall survival is 23 months. Lessons: This indicate that comprehensive treatment including immunotherapy may be helpful for inoperable DMPM patients with nasopharyngeal carcinoma accompanied with paraneoplastic syndromes.