BACKGROUND Pulmonary sequestrations often lead to serious complications such as infections, tuberculosis, fatal hemoptysis, cardiovascular problems, and even malignant degeneration, but it is rarely documented with medium and large vessel vasculitis, which is likely to result in acute aortic syndromes. CASE SUMMARY A 44-year-old man with a history of acute Stanford type A aortic dissection status post-reconstructive surgery five years ago. The contrast-enhanced computed tomography of the chest at that time had also revealed an intralobar pulmonary sequestration in the left lower lung region, and the angiography also presented perivascular changes with mild mural thickening and wall enhancement, which indicated mild vasculitis. The intralobar pulmonary sequestration in the left lower lung region was long-term unprocessed, which was probably associated with his intermittent chest tightness since no specific medical findings were detected but only positive sputum culture with mycobacterium avium-intracellular complex and Aspergillus. We performed uniportal video-assisted thoracoscopic surgery with wedge resection of the left lower lung. Hypervascularity over the parietal pleura, engorgement of the bronchus due to a moderate amount of mucus, and firm adhesion of the lesion to the thoracic aorta were histopathologically noticed. CONCLUSION We hypothesized that a long-term pulmonary sequestration-related bacterial or fungal infection can result in focal infectious aortitis gradually, which may threateningly aggravate the formation of aortic dissection.

Pyomyositis is an uncommon clinical scenario; it is usually associated with predisposing factors, including poorly controlled diabetes mellitus, trauma history, and immunocompromise. We discuss the case of an elderly woman with a 20‐year history of diabetes mellitus and remissive breast cancer after modified radical mastectomy and subsequent chemotherapy 28 years previously. The patient presented with severe shoulder pain and gradual swelling. After examination, pyomyositis was diagnosed and debridement surgery was performed. Culture of the wound samples showed the growth of Streptococcus agalactiae. During hospitalization, primary biliary cholangitis (PBC) was diagnosed incidentally, accompanied by poor glycemic control. After treatment with antibiotics for pyomyositis and ursodeoxycholic acid for PBC, the infection resolved in 8 weeks, and her glycemic control was improved after PBC treatment. It is possible that the long‐term untreated PBC worsened insulin resistance and aggravated diabetes mellitus in this patient. To the best of our knowledge, this is the first reported case of pyomyositis caused by an unusual pathogen, S. agalactiae, in a patient with newly diagnosed PBC.