食道ESD切除症例の病理学的検索成績

Pathological Study of the Endoscopic Submucosal Dissection of Esophageal Squamous Cell Carcinoma

要旨　食道扁平上皮癌のESD切除171病変を臨床病理学的に検討し，切除断端陽性例と局所再発ないしリンパ節転移再発例についての特徴を調べた．171病変はすべて一括切除が行われたが，腫瘍病変の大きさは長径3mm大から90mm大であった．切除断端陽性ないし疑陽性例は11病変で認められた．深部断端陽性例は2例でSM癌が認められ，うち局所再発は1例にみられた．側方断端陽性と考えられた9例中，局所再発は2例であり，T1a-LPM，T1a-EPの深達度であったが，側方断端に上皮異型像が認められ判定保留されていた．病理組職学的に切除断端判定に苦慮した症例では，切除時の熱変化による変性や挫滅（平均1,000μm），伸展固定時の組織崩壊と低異型度の腫瘍病変の良悪判断，非腫瘍性上皮異型などが存在する．リンパ節転移再発例は2例みられたが，ESD試料においてはly因子陽性例は少なかった．詳細な再検索でリンパ管侵襲が見い出された例もあった．再発例やリンパ節転移例のEMR組織において，腫瘍先進部のINFcを示す傾向がみられた．また，EMR 症例309病変を比較検討した結果，局所再発率は3.5％であったが分割切除が33例あり，この分割切除例では局所再発が11例（33％）にみられた．一括切除が可能なESDはEMRに比べ再発率は低く（1.7％），ESDによる切除は良好な成績であった．ESD実施時の正確な診断と範囲や，切除時ないし固定時の変性，挫滅などを考慮して切除断端を考え，病理診断において組織像,リンパ管侵襲，断端における低異型度の病変を見落とさないことが大切である．

　We reviewed 171 lesions treated with ESD excision of the squamous cell carcinoma of the esophagus, clinicopathologically, and examined the characteristis of cases with positive margins, local recurrence and lymphnodal recurrence.

　Excision en bloc was performed in all 171 lesions, but the size of the tumor lesions ranged in length from 3mm to 90mm. Eleven cases were positive or false positive on cut ends ; two “SM" cases were positive for vertical margins and one case had local recurrence. Nine cases were positive for lateral margins and two local recurrent cases were “T1a-EP" and “T1a-LPM" carcinoma with low grade malignancy on the marginal epithelium.

　For the cases where judgment of the excisied specimens was difficult, histologically there was heat change（an average of 1,000μm）in the excising and crush injury at the extensive fixation, and a judgment of malignancy because of the low grade epithelial atypia.

　Two lymphnodal recurrence cases were found, but there were few ly -factor positivity findings in the ESD specimens, and there were some cases in which lymphvascular invasion was found by detailed re-examination. In ESD tissue with recurrence and metastases to lymphnodes, that was a tendency to show INF c in the invasive front of the tumor. Also, in comparative study of 309 cases treated with EMR, the rate of local recurrence in EMR was 3.5%, and 33 cases were piecemeal resection which resulted in 11 cases of local recurrence（33%）. Because of the ESD method excising en bloc was possible, and there was a lower rate of in the rate of recurrence in comparison with EMR（1.7%）, and a high rate of curability was attained by using ESD.

　We have to consider denaturation in order to make a correct diagnosis at the time of performing ESD and, in the pathological diagnosis, it is important not to overlook histological findings such as the presence of tissue degeneration and crush-injury in resected margins, lymphvascular invasion and lesions of low-grade atypia in the margins.