Cíl: Prezentovat neobvyklý případ 49leté ženy s pozitivní anamnézou metastazujícího maligního melanomu, u které se při 18F-FDG PET/CT vyšetření po léčbě zobrazil enchondrom v hlavičce fibuly napodobující solitární metastázu maligního melanomu. Metodika: Pacientka v rámci kontroly efektu léčby absolvovala celotělové PET/ CT zobrazení, a to 60 minut po intravenózní aplikaci radiofarmaka 18F-FDG o aktivitě 386 MBq. Akviziční čas PET skenu byl 2,5 minuty na 15 cm projekci, celkem 14 projekcí. Kontrastní (i.v. + per os kontrast) CT sken byl proveden ve venózní fázi. Výsledky: 18F-FDG PET/CT prokázalo osteolytické ložisko s jemným sklerotickým lemem v hlavičce levé fibuly s zvýšenou akumulaci 18F-FDG. Vzhledem k pozitivní anamnéze metastazujícího maligního melanomu bylo vysloveno podezření na solitární metastázu a doporučena biopsie. Následně pacientka podstoupila resekci hlavičky fibuly a histologické vyšetření zjistilo přítomnost enchondromu. Závěr: Enchondrom může vykazovat zvýšenou ložiskovou akumulací 18F-FDG v kosti, a tudíž má schopnost napodobovat solitární metastázu maligního melanomu při PET/CT zobrazení a tím způsobit potenciální obtíže při hodnocení nálezu., Aim: To present a rare case report of the fibular head enchondroma mimics a solitary malignant melanoma metastasis on 18F-FDG PET/CT imaging. Method: The 49-year-old woman with positive history of the metastatic malignant melanoma after treatment underwent 18F-FDG PET/CT. The whole body PET/CT scan was obtained 60 minutes after intravenous injection of 18F-FDG (386 MBq). The PET scan acquisition time was 2.5 minutes per bed position for whole body imaging and fourteen bed positions were necessary. Contrast-enhanced CT (venous phase) provided both full CT evaluation (including intravenous and oral contrast) and PET attenuation correction. Results: The examination revealed 18F-FDG avid bone lytic lesion with the mild sclerotic border in the left fibular head. The PET/CT finding was suspected for solitary melanoma metastasis. The patient underwent surgery and enchondroma was proven by histopathology. Conclusion: Benign enchondroma shows increased 18F-FDG uptake in bone lesion and can mimic solitary malignant melanoma metastasis on PET/CT imaging and can cause potential pitfall in the PET/ CT evaluation., Jiří Doležal, Martin Slanina, and Literatura
The clinical outcome of 153 Graves' disease patients treated with a wide dose range of radioactive iodine-131 (RAI) was analyzed retrospectively. Six to nine months after the first dose of RAI 60 patients (39%) were hypothyroid (or rather thyroxine-substituted) and 26 (17%) were euthyroid, while 67 patients (44%) did not respond properly: in 32 (21%) their antithyroid drug (ATD) dose could be reduced but not withdrawn (partial response) and 35 (23%) remained hyperthyroid or the same dose of ATD was necessary (no response). The outcome did not correspond significantly to the administered activity of RAI (medians 259, 259, 222, and 259 MBq for hypothyroid, euthyroid, partial, and no response subgroups, respectively), or the activity retained in the gland at 24 h (medians 127, 105, 143, and 152 MBq). The effect was, however, clearly, and in a stepwise pattern, dependent on initial thyroid volume (17, 26, 33 and 35 ml, P < 0.001) or activity per gram tissue retained at 24 h (6.02, 4.95, 4.75, and 4.44 MBq/g, P = 0.002). Also, higher residual level of thyrotoxicosis at the time of RAI treatment was connected with worse outcome. The dose-dependency of outcome was further analyzed. When our sample was divided into tertiles, according to the adjusted dose, the same modest success rates (47%) were seen in the lower and middle tertiles. However, doses higher than 5.88 MBq/g (the upper tertile) resulted in success rate of 75%. Finer division into decils has shown a threshold-like increase in cure rate between the 7th and the 8th decil. In the first 7 decils (doses ≤ 6 MBq/g) the complete response rate was 45 to 50%, in the 8th decil (6.0 to 7.8~MBq/g) it rose to 80% and was not further increased with increasing dose. Direct comparison of higher (> 6 MBq/g, cure rate 80%) and lower (≤ 6 MBq/g, cure rate 46%) doses gave highly significant difference (P < 0.001). With our dosing range we found a dose-dependent clinical outcome that suggests an optimum delivered dose near 6.5 MBq/g, resulting in successful treatment of ca 80% patients. and J. Čepková, J. Horáček, J. Vižďa, J. Doležal