Pulmonary sequestration associated with pulmonary actinomycosis: A case report and literature review

Rationale: Pulmonary sequestration (PS), a rare pulmonary disease, arises from congenital pulmonary vascular dysplasia. Meanwhile, pulmonary actinomycosis is a purulent infection of lung lesions triggered by the inhalation of actinomycetes, which is also uncommon. Even rarer is the occurrence of pulmonary actinomycete infection secondary to PS. Herein, we present a case report of such a rare occurrence.

Patient concerns: The 21-year-old female patient had been erroneously diagnosed with pneumonia and tuberculosis, presenting symptoms of cough, sputum, and hemoptysis; however, the implemented anti-infection and antituberculosis treatments proved to be ineffective.

Diagnoses: The diagnosis of the sequestration in the right lower lung was confirmed through an enhanced chest CT scan and a 3-dimensional reconstruction of the pulmonary vessels.

Interventions: During the surgical video-assisted thoracoscopic resection of the right lower lobe lesion, it was discovered that the isolated lung tissue's blood supply vessel originated from the thoracic aorta. Additionally, the pathological examination revealed that the lung tissue of the right lower lobe lesion was infected with pulmonary actinomycetes.

Outcomes: Following thorough evaluation, the patient received a final diagnosis of pulmonary actinomycete infection that occurred secondary to right lower lung sequestration. Consequently, they underwent treatment consisting of high-dose penicillin administered for a period of 6 months post-operation. Over the course of the subsequent 23-month follow-up, no recurrence of the infection or abnormal CT scan findings were observed.

Lessons: Pulmonary sequestration bears clinical resemblance to pulmonary actinomycetes. In cases where recurrent episodes of pneumonia occur at the same location, and chest imaging indicates persistent lesions in the basal segment of the lower lobe near the spine, the possibility of PS should be considered. Prompt chest-enhanced CT and 3-dimensional reconstruction of pulmonary vessels are crucial for a definitive diagnosis. Imaging findings such as mass-like consolidation, cystic lesions, liquefactive necrosis, and pneumonia-like changes, coupled with typical air suspension signs and sulfur-like particles visible under tracheoscopy, suggest a potential pulmonary actinomycete infection. Timely biopsy is essential to confirm the diagnosis and prevent missed or incorrect diagnoses.