Umut ELBOĞA, Deniz DEMİR, Zeki ÇELEN, Ebuzer KALENDER, Mustafa BAŞIBÜYÜK, Mustafa YILMAZ

DİFERANSİYE TİROİD KARSİNOMALI HASTALARIN TAKİBİNDE ANTİ-TG ANTİKOR DÜZEYLERİNİN ÖNEMİ: OLGU SUNUMU

Diferansiye tiroid karsinomlu (DTK) hastalarda antitiroglobulin (anti-Tg) antikor varlığında tiroglo- bulin (Tg) ölçümlerinin güvenilirliği azalmaktadır. Anti-Tg varlığında Tg değerleri genellikle hatalı olarak düşük ölçülebilmektedir. Birçok çalışmada anti-Tg seviyelerindeki sebat ya da artışın kalıcı ve tekrarlayıcı hastalık için önemli bir risk faktörü olduğu rapor edilmiştir. Bazı çalışmalarda ise normal sınırlarda Tg seviyelerine sahip DTKlı hastalarda pozitif anti-Tg seviyelerinin tümör be- lirteci olarak kullanılabileceği rapor edilmiştir. Otuz iki yaşındaki papiller tiroid karsinomlu kadın hasta totale yakın tiroidektomi sonrası remmant ablasyonu için nükleer tıp kliniğine yönlendirildi. Operasyondan sonra hastaya remnant ablasyonu için 100 mCi 131I ile verildi. Ablasyon tedavisin- den yaklaşık 6 ay sonra tedavi cevaplarının değerlendirilmesi amacıyla radyoiyot tarama planlandı. Taramadan hemen önce hastanın uyarılmış Tg ve anti-Tg değerlerine bakıldı. Hastanın Tg değeri ölçülemeyecek kadar düşük, anti-Tg değeri 238 U/ml idi. Tanısal taramada tiroid yatağında postop/ post-ablatif bakiye tiroid dokuları ile uyumlu görünümler izlendi. Sonuç olarak DTKlı hastalarda normal sınırlarda Tg varlığında pozitif anti-Tg değerlerinin tümör belirteci olarak kullanılabilece- ğini, ayrıca pozitif anti-Tg seviyesi ile negatif radyoiyot taramanın FDG PET-BT görüntüleme için endikasyon olabileceğini düşünmekteyiz.

The Importance of anti-Tg Antibody Levels on the Follow- up of Patients with Differentiated Thyroid Carcinoma: Case Report

The reliability of thyroglobulin (Tg) measurements in patients with diffrentiated thyroid carcinoma (DTC) is decreased by the presence of anti-Tg antibodies (TgAb). In the presence of Tg Ab, levels of Tg can be usually mistakenly low. Most studies have reported that the persistence or a rising trend in Tg Ab concentrations is a significant risk factor for persistent and recurrent disease. Some studies reported that positive Tg Ab levels can be used as a tumor marker in DTC patients with undetectable Tg levels. Thirty-two year-old female patient with papillary thyroid carcinoma referred to nuclear medicine clinic for remmant ablation after near-total thyroidectomy. After surgery 100 mCi 131I was given to patient for remmant ablation. To control the ablation treatment efficacy, diagnostic whole body scan (DWBS) was planned approximately 6 months later. Just before DWBS, Tg and Tg Ab levels were measured, simultaneously with TSH. On DWBS, postop/ postablative thyroid remmants were seen on the thyroid bed. In conclusion we think that positive Tg Ab level can be used as a surrogate tumor marker in the presence of undetectable Tg level in patients with DTC. Also we think that positive Tg Ab and negative radioiodine scan may be an indication for FDG PET-CT scan.

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