ABSTRACT
El carcinoma paratiroideo (CPT) es un tumor poco frecuente que suele ser hiperfuncionante, produciendo un exceso de hormona paratiroidea. El hiperparatiroidismo produce trastornos del metabolismo óseo, como osteopenia y en ocasiones tumores pardos. Los tumores pardos son lesiones óseas benignas, pero localmente destructivas, cuyo diagnóstico diferencial con metástasis u otros tipos de tumores primarios puede ser complicado. La técnica habitual para la detección de patología paratiroidea es la gammagrafía con 99mTc-sestamibi, con una sensibilidad del 85100% y una especificidad cercana al 100% en adenomas paratiroideos, presentando cifras muy similares en la detección del CPT. Presentamos el caso de un paciente diagnosticado de hiperparatiroidismo de origen tumoral con lesiones óseas asociadas en el que la gammagrafía con 99mTc-sestamibi presentó un falso negativo en la detección de patología paratiroidea. Sin embargo, la PET/TAC-18F-FDG detectó el CPT y ayudó en el diagnóstico diferencial de las lesiones óseas asociadas, que fueron finalmente tumores pardos(AU)
Parathyroid carcinoma (PTC) is a rare malignant disease that is usually hyperfunctioning, which produces an excess of parathyroid hormone. Hyperparathyroidism causes bone metabolism disorders, as osteopenia and sometimes brown tumors. Brown tumors are benign but locally aggressive bone lesions, whose differential diagnosis with metastases or other primary malignancies may be complicated. 99mTc-Sestamibi scan is the usual procedure for the detection of parathyroid pathology, with a sensitivity of 85100% and specificity close to 100% in parathyroid adenomas, it having similar percentages in the detection of PTC. We present the case of a patient diagnosed of a malignant hyperparathyroidism associated with bone lesions in which the 99mTc-Sestamibi scan showed a false negative result in the detection of parathyroid condition. However, 18F-FDG-PET/CT detected the PTC and helped in the differential diagnosis of associated bone lesions, which were finally confirmed as brown tumors(AU)
Subject(s)
Humans , Male , Middle Aged , False Negative Reactions , Technetium Tc 99m Sestamibi , Carcinoma/diagnosis , Parathyroid Neoplasms/complications , Parathyroid Neoplasms/diagnosis , Positron-Emission Tomography/methods , Tomography, Emission-Computed/methods , Sensitivity and Specificity , Technetium Tc 99m Sestamibi/chemistry , Technetium Tc 99m Sestamibi/pharmacokinetics , Technetium Tc 99m Sestamibi/radiation effects , Carcinoma , Hyperparathyroidism/complications , Bone Diseases, Metabolic/complicationsABSTRACT
Both 99mTc sestamibi and 201Tl have been used in conjunction with 131I scintigraphy for follow-up of patients with thyroid cancer. The aim of the study was to determine if irradiation affects tracer uptake in papillary thyroid cancer cells. The human papillary carcinoma cell line (PAP/ES-1) used in this study was generated from a papillary thyroid tumour obtained after surgery. For the in vitro uptake studies cells were seeded at 2 x 105 cells/well into 12-well microtitre plates. Irradiation was performed with a 60Co source (total dose, 2 Gy and 10 Gy). After incubation at 37 degrees C the supernatants were saved for determination of the unincorporated activity. The reaction was stopped by washing the cells four times in ice cold phosphate buffered saline. Total cellular uptake was determined by measuring cell lysate radioactivity in a Compugammasystem and was expressed as per cent uptake per mg of total cellular protein. At continuous incubation 201Tl uptake was significantly (P<0.01) higher after radiation whereas no effect of irradiation was found on 99mTc sestamibi uptake. Pulsed experiments revealed that irradiated cells displayed a faster 201Tl efflux. The net tracer retention at 90 min was similar to 201Tl to that of 99mTc sestamibi. We conclude that 99mTc sestamibi kinetics in thyroid cancer are not affected by irradiation and may therefore be superior to 201Tl in the follow-up of thyroid cancer shortly after radiotherapy.
