

[摘要] 目的 探討18F-氟脫氧葡萄糖(18F-FDG)正電子發射計算機斷層掃描(PET-CT)顯像高代謝假性梅格斯(Meigs)綜合征(PMS)的臨床特點和鑒別診斷。
方法 報告1例PET-CT顯示高代謝的PMS同時伴有糖類抗原125(CA125)升高的病人的臨床資料,并結合相關文獻進行復習。
結果 本文病人臨床表現為盆腹腔囊實性包塊、CA125升高、大量腹水、CT增強掃描呈現強化及PET-CT顯像示蹤劑異常攝取增高,初步診斷為盆腹腔惡性腫瘤。然而,通過術前腹水細胞學檢查聯合CA125/CEA比值和術后病理檢查,最終確診為PMS。
結論PET-CT高代謝同時伴有CA125升高的PMS極易被診斷為惡性腫瘤,需借助術前腹水細胞學檢查聯合CA125/CEA比值和術后病理檢查明確診斷。
[關鍵詞] Meigs綜合征;平滑肌瘤;氟脫氧葡萄糖F18;正電子發射斷層顯像計算機體層攝影術;CA-125抗原;病例報告
[中圖分類號] R737.31
[文獻標志碼] B
[文章編號] 2096-5532(2024)06-0930-04
doi:10.11712/jms.2096-5532.2024.60.181
[開放科學(資源服務)標識碼(OSID)]
[網絡出版] https://link.cnki.net/urlid/37.1517.R.20241231.1451.007;2025-01-02 13:20:51
Pseudo-Meigs’ syndrome with hypermetabolism on 18F-FDG PET/CT: a case report and literature review
HAN Xiahui, XU Yuance, YAO Qin
(Department of Obstetrics and Gynecology, The Affiliated Hospital of Qingdao University, Qingdao 266000, China)
[Abstract] Objective To investigate the clinical features of pseudo-Meigs’ syndrome (PMS) with hypermetabolism on 18F-deoxyglucose (18F-FDG) positron emissiontomography-computed tomography (PET-CT), and discuss its differential diagnosis.
Methods "We reported a patient with PMS with hypermetabolism on PET-CT who also hadan increased carbohydrate antigen 125(CA125) level, and at the same time, relevant literature was reviewed.
Results "This patient had a cystic-solid mass in the abdominopelvic cavity showing enhancement on contrast-enhanced CT scan and abnormally elevated PET-CT tracer uptake, accompanied by an increased CA125 level and massive ascites.The initial diagnosiswas anabdominopelvic malignancy. However, the case was finally confirmed as PMS according to preoperative ascetic fluid cytology,the ratio of CA125 to carcinoembryonic antigen (CEA), and postoperative pathology.
Conclusion PMS with hypermetabolism on PET-CT and increased CA125 levelscan be easily misdiagnosed as a malignant tumor, and its diagnosis need confirmation with preoperative ascetic fluid cytology combined with CA125/CEA ratio and postoperative pathology.
[Key words] Meigs syndrome; leiomyoma; fluorodeoxyglucose F18; positron emissiontomography computed tomography; CA-125 antigen; case reports
梅格斯(Meigs)綜合征是一種罕見的以腹水和胸腔積液為特征的疾病,原發腫瘤通常為卵巢纖維瘤等卵巢良性腫瘤[1]。Meigs綜合征腹水形成的主要原因是液體通過腫瘤表面滲出,超過腹膜的重吸收能力,或腫瘤壓迫淋巴管和靜脈,導致回流受阻[2]。腹水通過膈肌和淋巴結進入胸膜腔,導致胸腔積液[3]。假性Meigs綜合征(PMS)與Meigs綜合征相似,但其原發腫瘤與Meigs綜合征不同,包括子宮平滑肌瘤等其他盆腹腔腫瘤[4]。如果不考慮潛在腫瘤,切除原發灶后胸腔積液和腹水都會消失。正電子發射計算機斷層掃描(PET-CT)顯示的代謝增高通常提示惡性病變,但也可能發生在一些正常組織、良性病變和炎癥部位。本文報告1例并發PMS的良性子宮平滑肌瘤病例,其PET-CT顯示高代謝,并伴糖類抗原125(CA125)升高。
1 病例報告
病人,女,49歲,因“腹脹持續加重1個月”于2023年4月20日就診于我院婦科。病人入院10個月前無明顯誘因出現腹脹,在外院就診考慮為胃腸不適,服用中藥和針灸治療效果不佳。病人近1個月出現嚴重腹脹伴納差。既往史:子宮肌瘤病史4年余,未定期復查;3年前行甲狀腺全切術。16歲月經來潮,月經周期和經血量正常,末次月經為2023年3月31日,孕1產 否認有腫瘤家族史。專科檢查:外陰為已婚已產型,陰道暢通,宮頸光滑無壓痛,子宮增大如孕5個月大小,雙側附件未捫及明顯異常;腹部觸及膨隆,腹肌緊張。彩色超聲檢查顯示盆腔內有一不均勻低回聲團塊,較大切面約20 cm×19 cm×14 cm,腹盆腔見液性回聲,考慮為腫瘤性腹水(大量)。初步診斷為:①盆腔包塊;②腹水;③子宮肌瘤;④甲狀腺術后。
病人入院后完善了常規檢驗和檢查。血清腫瘤標志物CA125為342 kU/L,CA125/CEA為300。兩次腹水和細胞蠟塊的病理檢查均未發現惡性腫瘤細胞。全腹增強CT顯示大網膜略增厚,腹盆腔內見大片液體密度影;盆腔內見邊界清晰、內部強化不均勻的較大軟組織密度影。PET-CT檢查顯示盆腔內有一巨大的軟組織包塊(圖1),其最大截面積約為133 mm×164 mm,密度不均勻,與兩側附件分界不清,示蹤劑攝取異常增加,原發病灶的最大標準攝取值(SUVmax)約為16.0,考慮可能為惡性腫瘤。盆腔大網膜區域可見斑塊狀軟組織灶,示蹤劑攝取輕度增加,SUVmax約為2. 考慮為轉移瘤。左上腹大網膜增厚、密度增高,示蹤劑輕度濃集,SUVmax約為1. 考慮為大網膜轉移可能。左側鎖骨上窩2枚淋巴結的示蹤劑攝取略有增加,SUVmax約為2. 不排除淋巴結轉移的可能。右側頸部Ⅲ區淋巴結的示蹤劑攝取也輕度增加,SUVmax約為1.9。病人因腹盆腔內巨大實性占位,可見液性回聲,且無絕對手術禁忌證,于2023年4月26日在全麻下行腹腔鏡復雜全子宮及雙側附件切除術。術中見盆腔內有淡黃色透明液體游離,總量約12 L(圖2A)。清除腹水后見子宮體略增大,宮底見一直徑約20 cm的漿膜下子宮肌瘤,表面血管豐富,呈怒張狀(圖2B)。肌瘤前壁與前腹壁和旁觀間致密粘連,左側壁與左側部分乙狀結腸也有致密粘連。雙側附件水腫樣改變,大網膜及盆腹腔臟器外觀無明顯異常。術后常規病理檢查:子宮平滑肌瘤,伴梗死;(雙側)輸卵管及卵巢組織為正常組織;腹水內未發現惡性腫瘤細胞。免疫組化檢查:平滑肌肌動蛋白(SMA)(+),CD10(-),Desmin(+),Ki-67(+)約2%,延胡索酸水合酶(FH)(-)(圖2C)。術后診斷為:子宮平滑肌瘤(FH陰性);PMS。術后1、6個月電話隨訪時,病人無腹脹和腹痛,飲食和體質量皆正常,外院復查CA125恢復正常。
2 討" 論
PMS在子宮平滑肌瘤中較少見。若盆腹腔囊實性包塊伴有CA125升高、大量腹水、CT增強掃描增強和PET-CT示蹤劑攝取異常增高,通常被認為是盆腹腔惡性腫瘤。子宮平滑肌瘤是最常見的婦科良性腫瘤,臨床上常表現為月經改變,較少出現CT明顯強化、CA125升高和盆腹腔大量腹水等惡性表現[5-8]。
多種腫瘤可引起PMS,如生殖細胞腫瘤、良性或惡性上皮腫瘤、轉移性腫瘤和子宮肌瘤等[9-12]。研究表明,PMS病人出現胸腹腔積液的可能原因是較大的腫瘤刺激腹膜,或壓迫下腔靜脈、局部靜脈及淋巴管而阻礙液體回流。此外,腫瘤本身釋放的毒素及炎癥產物也可能與胸腹腔積液的生成有關[13]。LIN等[14]報道了1例繼發于乳癌伴卵巢轉移的PMS病例,該病例腹水的產生可能與炎細胞因子和血管內皮生長因子水平增加有關。本文病人子宮肌瘤較大,術后常規病理報告顯示肌瘤伴有梗死。因此,不能排除肌瘤刺激腹膜產生腹水或肌瘤梗死發生炎性滲出的可能性。臨床上Meigs綜合征與PMS不容易區分,病人通常均表現為腹痛和盆腔包塊癥狀。然而,無論潛在的腫瘤類型如何,手術切除原發腫瘤后胸腔積液和腹水都會消失[15]。YAGUCHI等[16]報道了1例由巨大子宮肌瘤伴囊性變引起的PMS,該病人接受子宮肌瘤切除手術和腹水引流后,腹水未復發,這也支持了上述觀點。本文病人術后6個月內都無腹脹和腹痛,符合PMS的特征。
18F-氟脫氧葡萄糖(18F-FDG)是一種能量代謝示蹤劑,PET-CT利用 18F-FDG在體內的分布和攝取情況來評估腫瘤的良惡性或惡性腫瘤的惡性程度。良性腫瘤的葡萄糖代謝活性通常較低,而惡性腫瘤的葡萄糖攝取率可能較高。良性子宮肌瘤PET-CT檢查通常表現為輕、中度代謝增高,其中SUVmax是評估PET圖像上18F-FDG攝取程度的參數,可反映病變的代謝活性。然而,子宮肌瘤的SUVmax截斷值目前尚無統一標準。一項對47例子宮肌瘤病人進行PET-CT成像和超聲檢查的研究顯示,子宮肌瘤的SUVmax值為4.38±2.57[17]。然而,有研究結果顯示,0.5%~3.4%的子宮肌瘤表現出較高攝取陽性率[18],這給鑒定和診斷良性和惡性子宮腫瘤造成了困難。相關研究表明,只有提高SUVmax臨界值,才能提高診斷的準確性。KUSUNOKI等[19]研究發現,將SUVmax截斷值提高到7.5可以區分子宮肌瘤和子宮惡性腫瘤,從而避免不必要的手術。另有研究發現,使用其他示蹤劑如18F-氟氧化雌烷酮(18F-FES)或18F-氟脫氧胸腺嘧啶(18F-FLT)能夠更好地區分良性和惡性子宮腫瘤[20-21]。
LEE等[22]首次報道了1例經病理證實的良性子宮肌瘤,其18F-FDG攝取在PET-CT成像中異常增高,考慮該病人的高代謝與使用促性腺激素釋放激素激動劑有關。然而,子宮肌瘤高代謝的確切機制尚未明確,目前認為可能與以下幾個方面有關。①月經。有研究發現,絕經前子宮肌瘤婦女18F-FDG的攝取率顯著高于絕經后[23]。YOSHIDA等[24]也發現了這一現象,還發現月經周期增殖期的攝取率比其他時期略高。這種與月經相關的高攝取情況可能與子宮肌瘤的細胞豐富度以及雌激素依賴性有關。②肌瘤較大、多發,肌瘤變性以及肌瘤的血供豐富[17,25]。③FH缺陷(FH陰性)型子宮肌瘤。該型子宮肌瘤較少見,占所有類型子宮平滑肌瘤的0.4%~0.6%[26]。出現這種情況的主要原因是編碼FH的基因發生突變,從而減少了參與三羧酸循環的FH的含量。由于延胡索酸無法水解生成蘋果酸,使得氧化磷酸化受損,代謝向糖酵解轉移。因此,FH陰性的子宮肌瘤可快速消耗葡萄糖,并在PET-CT中表現出18F-FDG的高攝取率[27-28]。本文病人的子宮肌瘤巨大,免疫組化結果顯示為FH陰性,這可能是PET-CT中高代謝表現的重要原因。
伴有CA125升高的PMS也較少見。CA125通常用于輔助診斷卵巢癌和監測治療效果,但是其診斷卵巢癌的特異度較低[29-30]。CA125在子宮內膜異位癥、卵巢良性腫瘤和子宮平滑肌瘤中可能升高。有研究表明,子宮平滑肌瘤中CA125的升高與較大的肌瘤本身或腹水機械摩擦腹膜有關,從而增加了CA125在間皮細胞中的表達[13]。ABDELGAWAD等[5]報道了1例盆腔包塊伴大量腹水和CA125升高的病例,開始懷疑為卵巢癌,手術切除后,病理診斷為子宮平滑肌瘤。對于這種伴有大量腹水和CA125升高的盆腔包塊,很容易懷疑為惡性腫瘤。本文病人的PET-CT顯示代謝增加,進一步提示惡性腫瘤,這使得術前診斷非常具有挑戰性。在這種情況下,術前鑒別診斷可通過活組織病理學或細胞病理學檢查來確認[31]。在未行穿刺活檢的情況下,也可通過腹水細胞學檢查聯合CA125/CEA比值來判斷。然而,在這種情況下,鑒于活體組織檢查是診斷惡性腫瘤的金標準,對惡性腫瘤的診斷必須慎重。一項評估術前新輔助化療聯合手術有效性的Ⅲ期隨機對照試驗顯示,腹水細胞學檢查陽性且CA125/CEA比值>25時,晚期卵巢癌診斷假陽性率為3%[32-33]。盡管本文病人術前CA125/CEA為300,但在腹水和細胞蠟塊病理檢查中均未發現惡性腫瘤細胞,故診斷為惡性腫瘤的可能性較小。本文病人術前并未行活檢組織病理檢查,故術前無法明確排除惡性腫瘤。
綜上所述,對于伴CA125升高且PET-CT顯示高代謝的PMS,也應考慮良性腫瘤的可能性,可于術前通過活組織病理檢查聯合腹水細胞學檢查或CA125/CEA比值進行鑒別診斷。
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