Endocrine Abstracts

Introduction: – The "super bone scan" is a peculiar condition characterized by extremely high bone uptake compared to soft tissue, with no visualization of renal radioactivity.– Super bone scan has been described in relation to several conditions such as metastatic disease (prostate/breast cancer), metabolic bone disease (Paget’s disease/hyperparathyroidism) and myeloproliferative disorders.

Clinical Case: – A 75 year old man, having as ATCD: a HTA under treatment.– For one year, he has been suffering from diffuse bone pain, aggravated for the last 3 months, with the onset of FI, evolving in a context of AEG.– Phosphocalcic assessment revealed: hypercalcemia=133 phosphoremia=21, vit D =24, PTH =96, elevated PAL and correct renal function.– The check-up after vit D supplementation: hypercalcemia at 130 and PTH=71.– Cervical ultrasound: no abnormalities. Parathyroid cesta-MIBI scan: no argument in favor of a pathological parathyroid gland.– A whole body scan with technetium-99m methyldiphosphonate (Tc-99m MDP) was performed, showing heterogeneity of global fixation of the radiotracer on the whole axial and peripheral skeleton with an attenuation of the renal shadows evoking the "super bone scan".– In the sense of bone metastases: RT: asymmetric prostate, firm, bulging on the left side, ultrasound: prostatic hypertrophy at 42 cc heterogeneous seat of calcifications, PSA elevated at 9.8 with a free PSA/total PSA ratio =0.25= a prostate biopsy is planned.

Discussion: – The "super bone scan" situations can be related to metabolic pathologies (especially hyperparathyroidism) or secondary: a bone diseases either metastatic (prostate/breast cancer), or myeloproliferative disorders.– The PTH values in this patient are not comfortable for the diagnosis of hyperparathyroidism (primary/parathyroid carcinoma). And given the context (age, AEG, high PSA), we consider the diagnosis of paraneoplastic hypercalcemia. What about the image of parathyroid fixation on FDG PET? - Considering the high number of false positives on FDG-PET and the low risk of false negatives on cesta-MIBI scintigraphy.– The most probable diagnosis is considered to be: malignant hypercalcemia in the context of a paraneoplastic syndrome on bone metastases of a prostatic ADK. And that the parathyroid fixation on PET scan is a false positive.

Conclusion: – The "super bone scan" is a peculiar condition characterized by extremely high bone uptake compared to soft tissue, with no visualization of renal radioactivity.– May be of metabolic or secondary origin.– The etiological diagnosis must take into account the clinical context and discuss on a case-by-case basis.