Invasive mucinous adenocarcinoma (IMA) is a subtype of lung adenocarcinoma characterized by the presence of goblet or columnar tumor cells containing abundant mucin in the cytoplasm. IMA is relatively rare, accounting for 2% to 10% of all primary lung adenocarcinomas. Due to the lack of specificity in its clinical presentation and imaging features, IMA is highly prone to misdiagnosis or missed diagnosis in clinical practice. Previous studies have demonstrated that the prognosis of IMA is heterogeneous and closely related to tumor stage and radiological subtype. Patients with early-stage nodular-type IMA generally show a more favorable prognosis, whereas those with advanced pneumonic-type IMA tend to have poorer outcomes. Furthermore, due to the significant mucin secretion properties, IMA differs markedly from invasive non-mucinous lung adenocarcinoma in terms of pathological morphology, molecular characteristics, and prognosis. Although both subtypes are primarily treated with surgery, the application of emerging targeted and immunotherapies in IMA is still in the exploratory stage. This review aims to systematically summarize the etiology and pathogenesis, imaging features, pathological characteristics, treatment advances and prognosis of IMA, with the goal of providing valuable references for clinical decision-making.