Uterine leiomyosarcoma metastatic to thyroid shown by 18F-FDG PET/CT imaging.

About one third of focal thyroid uptakes in a fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) study are malignant, the most frequent histological type being papillary carcinoma. Metastases to the thyroid account for approximately 7.5% of thyroid malignancies and come mainly from kidney, lung, head and neck, and breast cancers. We report the case of a 64-year-old woman presenting a fast growing thyroid nodule whose primitive or metastatic origin was not obvious, for which 18F-FDG PET/CT helped in the diagnostic process and in the later management of the patient. Histopathologic findings finally revealed a metastasis of uterine leiomyosarcoma.

[Positron emission tomography in clinical oncology]. / Tomographie par émission de positons en oncologie clinique.

A NEW FORM OF MEDICAL IMAGING: Positron emission tomography (PET) is used for the non-invasive in vivo visualisation of biochemical cell processes. It reveals the metabolic characteristics of neoplastic lesions and hence their identification by compensating the lack of lesion specificity of radiological techniques. VARIOUS INDICATIONS: Using the current oncology marker, 18F-fluorodeoxyglucose (FDG), excellent results with PET have been established at all stages of neoplasia, notably for the diagnosis of initial malignancy and the identification of residual lesions and early detection of relapses. Moreover, the fact that the whole of the body can be explored makes PET the tool of choice in the control of the extension and operability of cancers. With the close correlation between imaging and the metabolism of the lesions, PET is the earliest and most precise for assessing the effects of treatment. LIMITS AND PERSPECTIVES: The existence of benign inflammatory FDG binding should lead to the development of markers of other metabolisms directly linked to cell proliferation. The lack of anatomical reference points characteristic of PET does not permit the precise localisation of the lesions detected and could be corrected by combining, in a single apparatus, the PET camera and an X scan, the anatomical resolution of which is irreplaceable. This type of equipment represents the development of a new branch of medical imaging, oncological imaging.

Uterine leiomyosarcoma metastatic to thyroid shown by 18F-FDG PET/CT imaging / Metástasis tiroidea de un leiomiosarcoma uterino detectada mediante 18F-FDG PET/TC

About one third of focal thyroid uptakes in a fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) study are malignant, the most frequent histological type being papillary carcinoma. Metastases to the thyroid account for approximately 7.5% of thyroid malignancies and come mainly from kidney, lung, head and neck, and breast cancers. We report the case of a 64-year-old woman presenting a fast growing thyroid nodule whose primitive or metastatic origin was not obvious, for which 18F-FDG PET/CT helped in the diagnostic process and in the later management of the patient. Histopathologic findings finally revealed a metastasis of uterine leiomyosarcoma (AU)

En los estudios de tomografía por emisión de positrones/tomografía computarizada (PET/TC) con fluorodesoxiglucosa (FDG), aproximadamente un tercio de las captaciones focales tiroideas son de naturaleza maligna, siendo lo más frecuente el carcinoma papilar de tiroides. Las metástasis intratiroideas, menos frecuentes, representan un 7,5% de los casos y se originan principalmente en tumores primarios de riñón, pulmón, cabeza y cuello, y mama. Se describe el caso de una mujer de 64 años que presentó un nódulo tiroideo de rápido crecimiento, cuyo origen primario o metastásico no estaba claro, en el cual la 18F-FDG PET/TC fue útil en la aproximación diagnóstica y en el manejo clínico de la paciente. El posterior análisis por anatomía patológica de la lesión confirmó el diagnóstico de metástasis de leiomiosarcoma uterino (AU)