下腹部に円形の腫瘤がある（△）．液状物質（※），脂肪組織（丸印），石灰化像（歯または骨↑），軟部組織（または腫瘤内出血：白矢印）を含み典型的な類皮嚢胞（皮様嚢腫：dermoid cyst，成熟嚢胞性奇形腫：mature teratoma）である．図１０〜図１２で少量だが腹水があり，図１〜図４の単純CTと比較して壁の造影効果は弱く，壁はやや肥厚しており捻転と診断する．図１３〜図１７の▲は同様の内容物を含む楕円形の腫瘤で，右卵巣のdermoid cystと思われ， ，子宮は左側へ偏移し，腹壁直下の病変（△）は左卵巣原発であり．図１３で捻転していない右卵巣腫瘤の脂肪組織（丸印）の壁は造影効果があり壁も薄い（▲）．手術及び病理所見：左卵巣腫瘍の捻転（図A）と右卵巣腫瘍．左卵巣卵管切除と右嚢腫切除を行った．いずれもdermoid cyst．歯，皮膚，皮膚付属器，血管，脂肪，神経，気管支上皮，気管支腺など多彩な３胚葉成分を伴う腫瘍で未熟成分は認めない．

文献考察：卵巣腫瘍捻転のCT所見
１）Kim YH, Cho KS, Ha HK, Byun JY, Auh YH, Rhim HC, Shim JC, Cha SJ, Hur G. CT features of torsion of benign cystic teratoma of the ovary. J Comput Assist Tomogr. 1999 Nov-Dec;23(6):923-8.
　PURPOSE: The purpose of this work was to evaluate the usefulness of CT scans for distinguishing torsed from uncomplicated benign cystic teratoma (BCT). METHOD: Retrospective analysis was performed in 14 torsed BCTs (14 patients) and in 23 uncomplicated BCTs (20 patients) for comparison. The features on CT scans were compared to the pathologic findings. RESULTS: CT findings indicating torsed BCT were the presence of eccentric wall thickening of >1 cm, peritumoral infiltration, and presence of enlarged solid tubal mass adjacent to the uterus (p
２）Rha SE, Byun JY, Jung SE, Jung JI, Choi BG, Kim BS, Kim H, Lee JM. CT and MR imaging features of adnexal torsion. Radiographics. 2002 Mar-Apr;22(2):283-94.
　In adnexal torsion, the ovary, ipsilateral fallopian tube, or both twist with the vascular pedicle, resulting in vascular compromise. Unrelieved torsion is likely to cause hemorrhagic infarction as the degree of arterial occlusion increases. Therefore, early diagnosis is important to preserve the affected ovary. Adnexal torsion commonly accompanies an ipsilateral ovarian neoplasm or cyst but can also occur in normal ovaries, usually in children. Although ultrasonography is typically the initial emergent examination, computed tomography (CT) and magnetic resonance (MR) imaging may also be useful diagnostic tools. Common CT and MR imaging features of adnexal torsion include fallopian tube thickening, smooth wall thickening of the twisted adnexal cystic mass, ascites, and uterine deviation to the twisted side. Uncommon imaging findings in adnexal torsion that are specific to hemorrhagic infarction include hemorrhage in the thickened fallopian tube, hemorrhage within the twisted ovarian mass, and hemoperitoneum. Additional imaging findings that can suggest hemorrhagic infarction include eccentric smooth wall thickening exceeding 10 mm in a cystic ovarian mass converging on the thickened fallopian tube and lack of contrast enhancement of the internal solid component or thickened wall of the twisted ovarian mass. Early diagnosis can help prevent irreversible structural damage and may allow conservative, ovary-sparing treatment. 　　PMID: 11896219