Metástasis de carcinoma diferenciado de tiroides en localizaciones infrecuentes: serie de 30 pacientes / Unusual metastases from differentiated thyroid carcinoma: series of 30 patients and review of literature

RESUMEN

RESUMEN Introducción Las metástasis son la principal causa de mortalidad específica en carcinoma diferenciado de tiroides (CDT). Las localizaciones más frecuentes son el pulmón y el hueso. El compromiso de otros sitios es inusual. Se desconoce el impacto que tienen en la evolución y sobrevida de los pacientes. Objetivos Evaluar la prevalencia de metástasis infrecuentes (MI) en pacientes con CDT, sus características clínico-patológicas y el impacto en la mortalidad. Material y métodos: Estudio multicéntrico retrospectivo. Se incluyeron pacientes con CDT y MI (diferentes de pulmón y hueso). Se analizaron las características basales, las localizaciones de las MI, el subtipo histológico, el tiempo de aparición desde el diagnóstico inicial (sincrónicas o metacrónicas), sintomatología asociada. Resultados La localización más frecuente fue el sistema nervioso central (31%). El 76,6% fueron metacrónicas, y presentaron criterios de refractariedad al yodo en 76,6% de los casos. La mitad de los pacientes presentó síntomas específicos. En 73,28% de los casos implicaron cambios en la conducta terapéutica. 19 pacientes (63,3%) fallecieron a causa de la enfermedad, con una mediana de sobrevida desde el diagnóstico de la MI de 11 meses. La sobrevida fue menor en pacientes con MI yodorefractarias y sintomáticas. Conclusiones: Las MI tuvieron una prevalencia baja, y se presentaron en forma metacrónica. Determinaron cambios en la estrategia terapéutica y se relacionaron con la mortalidad específica en más de la mitad de los casos, lo que resalta la importancia de una estadificación precisa en pacientes con enfermedad avanzada.

ABSTRACT

ABSTRACT Introduction Complications related to metastatic disease are the main cause of specific mortality in differentiated thyroid cancer (DTC.) The most common sites of metastses are lung and bone. Other localizations are infrequent and they have been reported as isolated cases or small series. The impact of unusual metastases (UM) in patient management and prognosis remains largely unknown. Objectives To retrospectively evaluate the prevalence of UM in DTC patients, define their clinical-pathological characteristics and analyze its relevance in management and mortality. Patients and methods: We retrospectively reviewed file records from 7 databases. DTC patients who had metastatic disease in sites different from lung or bone were included. UM were diagnosed by i) biopsy and/or ii) radioiodine (RAI) bone uptake + elevated thyroglobulin (Tg) levels and/or c) bone uptake of 18-FDG in the PET-CT scan + elevated Tg levels. We analyzed histopathologic characteristics, clinical presentation, localization, time of diagnosis (synchronic vs. metachronic presentation), diagnostic and therapeutic modalities and final outcome of patients. Results UM were diagnosed in 30 out of 2986 DTC patients (1%). The most common site of UM was the central nervous system (CNS 31%). Twenty percent of the patients had more than one UM. In 93% of the cases, UM coexisted with either lung and/or bone metastases and/or locoregional disease. Papillary histology was found in 75% of cases; 76.6% were metachronic with DTC diagnosis, and 76.6% fulfilled radioiodine refractoriness criteria. Half of the patients reported symptoms related to the UM. In 73.2% of the cases, therapeutic decisions were influenced by the diagnosis of the UM. Nineteen patients (63.3%) died of DTC related causes, with a mean survival of 11 months. The most frequent cause of death was CNS progression. Survival was shorter in patients with radioiodine refractory and symptomatic lesions. Conclusions Prevalence of UM was low; they were predominantly metachronic and iodine refractory. UM were found in patients with widespread disease, however, treatment strategies were modified by their diagnosis. UM were associated with poor survival and disease specific mortality.