The Value of the 123 I-MIBG Scintigraphy in Diagnosis and Follow-Up of Patients with Pepper Syndrome

Full text: Objective: The poster highlights the importance of scintigraphy with 123 I-MIBG in the complete evaluation of a patient with Pepper syndrome. Pepper syndrome is a particular form of the metastatic neuroblastoma in stage 4S (hepatic metastasis without bone involvement) with a good prognosis, which affects mainly newborns. MIBG (metaiodobenzyl-guanidine) being an analogue of norephinephrine - is captured (active mechanism) by the neuroendocrine cells and is concentrated in the medula of the adrenal glands, sympathetic paraganglia, myocardium sympathetic nervous terminations, APUD system and in the tumours originating from these structures. Materials and Methods: EN, 3 months old, feminine sex, suspected of having 4S stage neuroblastoma (Pepper syndrome) has been evaluated by a scintigraphic examination 24 hours after intravenous injection of 80 MBq 123 I-MIBG. We used a dual-head GE gamma camera, LEUHR collimator with parallels channels for low energy, with high resolution; energy window:159 keV +/- 10%. We performed static images of the cranium (anterior, posterior and lateral view), thorax, abdomen, pelvis and limbs (anterior and posterior view). Thyroid gland was blocked with Lugol. We have repeated the scintigraphic examinations at 3, 4, 6 and 7 months after the initial exam. Results and Discussions: First examination confirmed the diagnosis of Pepper syndrome putting in evidence a hyper fixation of the radio pharmaceutic in the right abdominal side corresponding with the primitive tumour of the adrenal medula; a heterogeneous hyper fixation of the liver evoking a multi nodular secondary hepatomegaly and some hyper fixations focalized to the cranial box (frontal right), to the superior epiphysis of the left tibia and to the superior extremity of the left femur (osteomedullary invasion). The next examinations have shown an amelioration of the scintigraphic imaging of the abdominal localisations but also of the osteomedullary ones. The scintigraphy has been correlated very well with the others morphological imaging investigations (CT, MRI). Conclusions: With a specificity of 100% and a sensitivity of 95% the scintigraphy with 123 IMIBG became the gold standard in the diagnosis (level of recommendation A), the staging (the presence and the localisation of the metastasis), the therapy decision, the evaluation of the response and the follow up of the patients with Pepper syndrome. (author)