Pulmonary mucinous adenocarcinoma: A case report and literature review

Rationale:Pulmonary mucinous adenocarcinoma (PMA) is a rare subtype of lung adenocarcinoma. Computed tomography images of PMA show pneumonia-like findings, solitary pulmonary nodules or ground-glass opacity with consolidation. Misdiagnosis can delay genetic diagnosis. This article reported a case of PMA presenting with unique imaging findings.Patient concerns:An 85-year-old female patient was admitted to our hospital with persistent-cough and expectoration. Anti-infection treatment was largely ineffective.Diagnoses:Bronchoscopy with bronchoalveolar lavage and liquid-based cytology revealed the presence of tumor cells. Lung biopsy confirmed the diagnosis of PMA.Interventions:Symptomatic treatment was administrated, including anti-infection, relief of cough and expectoration. Bronchoscopy and lung puncture were performed to help clarify the cause of the disease.Outcomes:The patient's course was uneventful, and she was discharged in good condition. After admission, the patient continued to receive anti-tumor immunotherapy in the oncology department.Lessons:PMA is a subtype of lung adenocarcinoma and has a low incidence. PMA usually presents with atypical clinical symptoms and signs, and it is difficult to be diagnosed based on imaging findings. It is often undiagnosed and misdiagnosed. Clinicians must increase awareness about the need for timely diagnosis, so as to develop more targeted treatment and achieve a better prognosis.