尾田 誠一郎

小児の歯原性粘液線維腫の治療は、可及的に低侵襲の治療が求められる。患者は8歳男児、右側下顎骨のX線透過像の精査目的に当科を受診した。単房性、境界明瞭なX線透過像を認めた。生検の結果、歯原性粘液線維腫の診断であった。生検時に可及的に腫瘍を摘出し、開放創とした。10ヵ月後、骨増生を確認し、顎骨形態を温存して残存腫瘍の摘出と骨面の削除を行った。術後3年8ヵ月経過し、再発を認めず経過は良好である。(著者抄録)

筋強直性ジストロフィーは常染色体優性遺伝性疾患である。筋強直性ジストロフィー患者の全身麻酔下手術では、麻酔薬と筋弛緩薬の効果遅延、悪性高熱症、循環器系合併症、呼吸器系合併症の問題から周術期管理に配慮を要する。今回、32歳女性の先天型筋強直性ジストロフィー患者に対して全身麻酔下に智歯の抜去を行った1例を経験したので報告する。全身麻酔法は筋弛緩薬を使用せず、プロポフォールおよびレミフェンタニルによる全静脈麻酔として予定通り手術を終えた。周術期の経過は良好で重篤な合併症を生じなかった。筋強直性ジストロフィー患者には慎重な周術期管理が求められる。(著者抄録)

症例は80歳女性で、右側頬部の違和感を自覚しており、歯科医院で右側頬粘膜下に腫瘤を指摘され、精査目的で当科を紹介受診した。MRIでは腫瘤の境界は明瞭で、T1強調像で中間の低信号、T2強調像で不均一な淡い高信号を呈し、Gd造影T1強調像にて不均一に造影された。局所麻酔下に生検を施行し黄色肉芽腫の病理組織学的診断を得て、全身麻酔下に右側頬粘膜腫瘍摘出術を施行した。口腔内より腫瘍直上の粘膜に切開を加え、腫瘍を周囲組織から剥離摘出した。腫瘍は黄色充実性であり、周囲組織との剥離は比較的容易であった。術後2年8ヵ月経過しているが、再発を認めず経過良好である。病理組織学的所見では、粘膜上皮下に淡明、泡沫、顆粒状の細胞質を有する泡沫細胞の増生を認め、周囲被膜は認められなかった。免疫組織化学染色にて、泡沫細胞はCD68に陽性、S-100蛋白とSOX10は陰性であり、黄色肉芽腫と診断した。

類天疱瘡は、上皮下水疱を呈する自己免疫性水疱症である。2007年から2017年の間に類天疱瘡と診断された24例について臨床病理学的検討を行ったので報告する。内訳は、粘膜類天疱瘡が21例、水疱性類天疱瘡が3例であった。性別は男性5例、女性19例、年齢は44歳から91歳(中央値65.5歳)であった。口腔内での発生部位は歯肉が19例と最も多く、頬粘膜が7例、口蓋が6例であった。口腔内病変のみ認めたのは18例であった。治療法は、ステロイドの全身投与が12例、局所投与が12例であった。局所投与の12例中8例は、ミノサイクリン塩酸塩、ジアフェニルスルフォンおよびニコチン酸アミドが単独または併用で投与されていた。全例の病状は改善し、現在も再燃に注意しながら経過観察を行っている。類天疱瘡は、口腔内のみに病変を認める症例も多く、皮膚科と連携し早期に診断し適切な治療を行う必要があると思われた。(著者抄録)

Autophagy acts as a host-defense system against pathogenic microorganisms such as Group A Streptococcus (GAS). Autophagy is a membrane-mediated degradation system that is regulated by intracellular membrane trafficking regulators, including small GTPase Rab proteins. Here, we identified Rab30 as a novel regulator of GAS-containing autophagosome-like vacuoles (GcAVs). We found that Rab30, a Golgi-resident Rab, was recruited to GcAVs in response to autophagy induction by GAS infection in epithelial cells. Rab30 recruitment was dependent upon its GTPase activity. In addition, the knockdown of Rab30 expression significantly reduced GcAV formation efficiency and impaired intracellular GAS degradation. Rab30 normally functions to maintain the structural integrity of the Golgi complex, but GcAV formation occurred even when the Golgi apparatus was disrupted. Although Rab30 also colocalized with a starvation-induced autophagosome, Rab30 was not required for autophagosome formation during starvation. These results suggest that Rab30 mediates autophagy against GAS independently of its normal cellular role in the structural maintenance of the Golgi apparatus, and autophagosome biogenesis during bacterial infection involves specific Rab GTPases.

腸管ベーチェット病が疑われた再発性アフタ性潰瘍の1例を経験したので報告する。患者は40歳女性。口腔内の難治性アフタ性潰瘍を主訴に当科を受診した。眼症状、皮膚症状および外陰部潰瘍は認めず、再発性アフタ性潰瘍の診断にて副腎皮質ステロイド軟膏にて経過観察を行った。しかし、初診から4年後に血便を認め、下部消化管内視鏡検査を施行したところ、盲腸に複数の潰瘍を認め、腸管ベーチェット病が疑われた。(著者抄録)

UNLABELLED: The standard treatments for oral leukoplakia range from careful observation to complete resection. No surgical intervention is chosen for several supposable reasons. Surgical treatment and no surgical treatment for oral leukoplakia have no defined basis for comparisons, and few studies have reported on the long-term outcomes of oral leukoplakia without surgery. OBJECTIVES: This study aimed to identify the important factors using a long-term wait-and-see policy in patients with oral leukoplakia. MATERIALS AND METHODS: In total, 237 lesions from 218 patients selected for non-surgical therapy between 2001 and 2010 were analyzed. On the basis of long-term follow-up data, lesions were classified as unchanged, reduced, disappeared, expanded, and malignantly transformed. RESULTS: In total, 135 (57.0%) lesions remained unchanged, 30 (12.7%) lesions were characterized by a reduction in size or clinical severity, and 44 (18.6%) lesions had disappeared. Another 17 (7.2%) lesions resulted in spread or clinical deterioration, and 11 (4.6%) lesions developed oral squamous cell carcinoma. CONCLUSIONS: We demonstrated a cumulative malignant transformation rate of 11.6% in 10years without resection. The lesions that were nonhomogeneous, and higher degree of epithelial dysplasia, located on the tongue were likely to progress into cancer. In addition, 32.5% of lesions without surgical treatment were reduced or disappeared. There is a possibility that removal of considerable irritation for a long time contributes to the treatment of this disease. The development of appropriate treatments for oral leukoplakia is required, which will enable successful differentiation between surgical and observation cases.

Autophagy plays a crucial role in host defence by facilitating the degradation of invading bacteria such as Group A Streptococcus (GAS). GAS-containing autophagosome-like vacuoles (GcAVs) form when GAS-targeting autophagic membranes entrap invading bacteria. However, the membrane origin and the precise molecular mechanism that underlies GcAV formation remain unclear. In this study, we found that Rab17 mediates the supply of membrane from recycling endosomes (REs) to GcAVs. We showed that GcAVs contain the RE marker transferrin receptor (TfR). Colocalization analyses demonstrated that Rab17 colocalized effectively with GcAV. Rab17 and TfR were visible as punctate structures attached to GcAVs and the Rab17-positive dots were recruited to the GAS-capturing membrane. Overexpression of Rab17 increased the TfR-positive GcAV content, whereas expression of the dominant-negative Rab17 form (Rab17 N132I) caused a decrease, thereby suggesting the involvement of Rab17 in RE-GcAV fusion. The efficiency of GcAV formation was lower in Rab17 N132I-overexpressing cells. Furthermore, knockdown of Rabex-5, the upstream activator of Rab17, reduced the GcAV formation efficiency. These results suggest that Rab17 and Rab17-mediated REs are involved in GcAV formation. This newly identified function of Rab17 in supplying membrane from REs to GcAVs demonstrates that RE functions as a primary membrane source during antibacterial autophagy.