Possibilities of single photon emission tomography in the diagnosis of bone metastases in patients with disseminated medullary thyroid carcinoma (case report)

The study objective : using a clinical example to demonstrate possibilities of single photon emission computerized tomography (SPECT) in combination with computed tomography (CT) in identifying latent bone metastases, taking into account the dynamics growth of serum basal calcitonin. Materials and methods . Patient S., 60 years old, visited N.N. Blokhin National Medical Research Center of Oncology for consultation on multiple lung metastases of cancer of unknown primary. Results. Taking into account basal calcitonin level, immunohistochemistry, ultrasound investigation andfine-needle aspiration biopsy of the node in the right thyroid lobe a diagnose of medullary thyroid cancer was made. CT revealed multiple metastases in both lungs. Specialist erformed thyroidectomy with central lymphadenectomy and facial neck dissection on both sides. During next four months basal calcitonin level increased twice. Control contrast CT lung screening showed the growth of previously identified metastases and the appearance of multiple new ones. Bone scan showed focuses of increased radio-pharmaceutical accumulation in the area of 7 h left rib, left iliac wing, in the left bones of cranial vault, in C 7 , Th 6 , Th 9 , Th I2 vertebrae and right foot bones. Additional examination using SPECT/CT (from the skull base to the hip joints) revealed metastases in corpuses of Th 9 , Th I2 vertebrae and the left iliac wing, and suspicion for metastasis in 7 h left rib. Magnetic resonance imaging (MRI) confirmed metastasis in Th 9 , Th I2 , L 3 vertebral bodies and in the left iliac wing. Conclusion. Conclusion . In this clinical example, SPECT/CT allowed to correctly detect metastases in both Th 9 and Th I2 vertebrae while bone scan was questionable, and MRI showed an additional damage of L 3 vertebra. Changes in the 7 h left rib could not be verified using CT, although this changes may be an emerging metastasis. Obviously, extensive use of radiation methods does not guarantee complete identification of all pathological focuses, it therefore allows assessing the prevalence of the pathological process. It is crucially important to control calcitonin level in these patients, since its rapid growth allowed suspecting additional distant metastases.