田中 由美¹, 藤原 宗典¹, 濵崎 直樹², 塩谷 直久², 柴 五輪男³, 今井 照彦³, 林田 幸治⁴, 中村 武彦⁵, 室 繁郎⁶, 平井 都始子⁷

Yumi TANAKA¹, Munenori FUJIWARA¹, Naoki HAMAZAKI², Naohisa SHIOYA², Iwao SHIBA³, Teruhiko IMAI³, Koji HAYASHIDA⁴, Takehiko NAKAMURA⁵, Shigeo MURO⁶, Toshiko HIRAI⁷

¹平成記念病院臨床検査課, ²塩谷内科診療所, ³済生会奈良病院内科, ⁴済生会奈良病院臨床検査部, ⁵平成記念病院内科, ⁶奈良県立医科大学呼吸器内科学講座, ⁷奈良県立医科大学総合画像診断センター

¹Department of Clinical Laboratory, Heisei Memorial Hospital, ²Shioya Clinic of Internal Medicine, ³Department of Internal Medicine, Saiseikai Nara Hospital, ⁴Department of Clinical Laboratory, Saiseikai Nara Hospital, ⁵Department of Internal Medicine, Heisei Memorial Hospital, ⁶The Department of Respiratory Medicine, Nara Medical University Hospital, ⁷The Department of General Diagnostic Imaging Center, Nara Medical University Hospital

キーワード : ultrasonography of respiratory tract, respiratory system, chest wall abscess, fistula, pyothorax necessitates, lung ultrasonography

超音波診断による胸腔内の液体成分の検出能は非常に高く，Ｘ線では指摘できないような極めて少量の胸水でも描出可能である．これまで膿胸を含め，胸水の診断に超音波検査が有用であることは多数報告されてきた．しかし胸壁膿瘍における超音波所見についてはほとんど報告がない．このたび，体表からの超音波検査が胸壁穿孔性膿胸の診断に有用であった1例を経験したので報告する．症例は69歳男性，胃癌，肺癌の術後経過中に右前胸部に腫瘤が出現した．胸部CTで肺癌の再発（癌性胸膜炎，皮下浸潤疑い）と診断され紹介入院した．超音波検査では，無数の点状エコーを有する胸水や胸壁内の楕円形の低エコー病変を認めた．壁側胸膜の一部が破綻し，胸腔と胸壁の低エコー病変の間に瘻孔を認めた．胸水が胸腔と胸壁の間を行き来する流動像を認め，膿胸の胸壁への穿破が疑われた．胸腔穿刺により膿胸と診断し，胸腔ドレナージの結果，胸壁腫瘤もほぼ消失した．超音波検査はリアルタイムでの観察が可能であり，胸壁穿孔性膿胸の診断にも有用である可能性が示された．

The sensitivity of ultrasound to detect liquid components in the thoracic cavity is very high, and it is possible to visualize even very small pleural effusions that cannot be discerned by X-ray. There have been many reports that ultrasonography is useful for the diagnosis of pleural effusion, including empyema. However, there have been few reports of chest wall abscess. We report a case of empyema necessitatis that was diagnosed with ultrasonography from the body surface. A 69-year-old man had a mass on the right chest wall during the postoperative course of gastric and lung cancer. He was diagnosed with pleural recurrence of lung cancer and was suspected to have subcutaneous infiltration based on chest CT, and was admitted to the hospital for referral. Ultrasonography showed pleural effusion and oval hypoechoic lesions in the chest wall. A fistula between the pleural cavity and the hypoechoic lesion in the chest wall was detected on ultrasonography. Pleural effusion was seen to flow from the pleural cavity to the chest wall to and fro. We suspected pyothorax necessitatis and made a diagnosis of pyothorax based on thoracentesis. The chest wall mass disappeared for the most part with thoracic drainage. Real-time observation using ultrasonography could be useful for the diagnosis of empyema necessitatis.