食道m3・sm癌の最新の診断―X線診断の立場から

Usefulness of X-ray Examination for Superficial Esophageal Cancers Invaded More Deeply Than the Muscularis Mucosae

要旨　当科におけるm₃以深食道表在癌52例の最深部X線所見について，最深部の形態により隆起型（19例）と陥凹平坦型（33例）に分けて検討し以下の結果を得た．①隆起型では正面像で，大きさ16mm以上，または10mm以上かつ高さ0-Iはsm_{2, 3}癌であった．②隆起型のうち0-IIa＋IIc型，m_3a癌（粘膜筋板に接するのみ）5例では4例（80％）に側面所見で伸展性の保たれた偽硬化が認められ鑑別診断に有用な所見であった（感度80％，特異度93％）．③特殊な形態の0-Isep，sm_{2, 3}癌では側面変形の乏しい症例がみられた．④陥凹平坦型m₃癌では長径2mm以下の微小な浸潤部をX線で指摘するのは困難であった．⑤陥凹平坦型における側面変形では局所的な直線化がm_3b癌（粘膜筋板に浸潤するもの），およびsm₁癌の診断に有用であった（感度80％，特異度83.3％）．⑥陥凹平坦型における側面変形ではsm_{2, 3}癌12例中9例（75％）が陰影欠損，不整硬化を示した（感度75％，特異度91％）．以上，今回の検討から隆起型病変では隆起最大径と高さがsm_{2, 3}癌の診断に，側面変形の偽硬化が粘膜筋板に接する程度のm₃癌の診断に有用な所見であった．また，陥凹型病変では粘膜筋板に浸潤するm₃およびsm₁癌とsm_{2, 3}癌の鑑別には，側面像が直線化までか，あるいは陰影欠損，不整硬化を示しているかを読影することで鑑別可能と考えられた．

　In order to clarify the accuracy of X-ray examination for diagnosis of the depth of invasion, we analyzed fifty-two cases of superficial esophageal cancers that had invaded more deeply than the muscularis mucosae. Subjects were divided into the two categories which showed protruding type (19cases) and depressed or flat type (33cases). The results were as follows ; ① In the en-face X-ray view of the protruding-type ca, the protrusions larger than 16mm in diameter or gross type 0-I which is larger than 10mm were diagnosed as sm_2,3 ca, respectively. ② In the lateral view of the protruding-type ca, gross type 0-IIa＋IIc m_3a ca (just attached to the muscularis mucosae) deformity of pseudo-rigidity was shown in 4 of the 5cases (sensitivity : 80％, specificity : 93％). ③ Some cases of peculiar gross type 0-Isep sm ca lacked definite lateral deformity. ④ In depressed or flat-type ca, it was impossible to detect the pin-point invasion less than 2mm in diameter. ⑤ In depressed or flat type-ca, m_3b (invading into the muscularis mucosae) or sm₁ ca, focal straightening in the lateral view was shown (sensitivity : 80％, specificity : 83.3％). ⑥ In depressed or flat type-ca, sm_2,3 ca, a marginal defect or irregular rigidity in 9 of the 12cases was shown (sensitivity : 75％, specificity : 91％). Conclusions ; In the en-face view of the protruding type-ca, the diameter and the height of the protrusions were useful for diagnosing sm_2,3 ca, and pseudo-rigidity was the specific finding for gross type 0-IIa＋IIc m_3a ca in the lateral view. In the lateral view of the depressed or flat type-ca, detecting the focal straightening and the marginal defect or irregular rigidity enabled us to distinguish m_3b or sm₁ ca from sm_2,3 ca.