逆行性後骨間皮弁形成術を行ったBowen病の1例

Bowen's Disease Treated with a Reversed Posterior Interosseous Flap in a Patient with Rare Vascular Anatomical Variation. Case Report

　症例は78歳の男性で，左手関節尺側部のBowen病の診断で切除術を受けた．7年後に右膝蓋骨骨折を受傷し入院した際に，同部位に表皮の不規則な肥厚と不全角化や痂皮形成がみられ，再発と判明した．腫瘍切除術後に生じた皮膚欠損を，逆行性後骨間皮弁で被覆した．近位皮膚穿通枝の走行は筋間中隔に一致せず総指伸筋・小指伸筋の深部をくぐり橈側寄りから皮膚に到達し，さらに中央・遠位部の皮膚穿通枝は欠損し，稀な解剖学的変異を伴っていた．後骨間動脈には多彩な解剖学的変異があり，術中に臨機応変な対応を迫られる場合がある．

　A 71-year-old man presented with Bowen's disease on the ulnar side of the left wrist, and the lesion was resected.　Seven years later he injured his right patella and was hospitalized, and irregular thickening and incomplete cornification were noted on his left wrist.　Since a skin biopsy indicated a recurrence of Bowen's disease, we removed the lesion surgically and covered the surgical defect with a reversed posterior interosseous flap.　However, the course of the proximal skin perforator artery did not conform to the division between the muscles and instead passed through the deep part of both the extensor digitorum communis and extensor digiti minimi toward the radial aspect of the forearm.　Loss of the skin perforators of the central and distal portions was identified as a rare anatomical variation in this patient.　We therefore elevated the reversed island flap with the next proximal arterial branch.　It is important to be aware that plans for reversed posterior interosseous flaps may need to be changed intraoperatively.