Primary　pulmonary　malignant　melanoma　(pPMM)　is　an　exceptionally　rare　type　of　primary　malignant　tumor.　The　present　study　reports　a　unique　case　of　pPMM　in　a　54-year-old　woman.　Surgical　resection　revealed　a　tumor　localized　around　the　bronchus,　showing　nodular　growth　with　relatively　well-defined　borders　and　no　evidence　of　local　or　distant　metastasis.　To　further　characterize　this　rare　pPMM,　histological　analysis,　immunohistochemistry,　sanger　sequencing　and　next-generation　sequencing　were　conducted.　Histologically,　the　tumor　exhibited　biphasic　differentiation,　with　both　epithelial-like　and　spindle　cell-like　features,　as　well　as　high-grade　characteristics,　including　significant　atypia,　necrosis　and　a　high　mitotic　index.　Key　diagnostic　features　of　malignant　melanoma　were　evident,　including　prominent　red　nucleoli　and　melanin　pigmentation.　Immunohistochemistry　confirmed　the　presence　of　melanoma　markers　and　demonstrated　a　loss　of　H3K27Me3　expression.　The　programmed　death-ligand　1　positivity　rate　of　the　tumor　was　60%.　NGS　identified　a　mutation　in　the　TP53　and　NTRK3　genes,　but　no　BRAF　mutation　was　detected.　This　case　report　highlights　the　unique　presentation　of　pPMM　with　H3K27Me3　loss　and　provides　insights　into　its　genomic　profile,　pathogenesis　and　natural　history.