Metastatic carcinomas to the thyroid are quite rare in daily cytology practice. However, when present they may produce a diagnostic dilemma, particularly when they share some morphologic similarities with primary thyroid lesions and when occurring in patients with occult malignant history. Herein, we report a case of metastatic gastric signet ring cell carcinoma to the thyroid. Our patient presented with an isolated right thyroid nodule, which was clinically considered to be a primary thyroid neoplasm. Fine-needle aspiration (FNA) cytology of the nodule revealed a cellular specimen with cohesive fragments and scattered individual neoplastic cells. The neoplastic cells had enlarged nuclei, fine chromatin, and inconspicuous nucleoli. Nuclear crowding, molding, and grooving were prominent. Intranuclear inclusion-like clearance was identified. Some tumor cells also had eccentric nuclei, creating a signet ring cell appearance. The colloid was scant. These cytological features may be seen in cases of papillary thyroid carcinoma or signet ring cell follicular adenoma; however, the presence of the signet ring cells is unusual in primary thyroid lesions and raises the possibility of a metastatic lesion to the thyroid. In our case, the tumor cells were positive for AE1/AE3, mucicarmine, and periodic acid-Schiff, but negative for thyroglobulin and thyroid transcription factor-1. The patient was also found to have a 3.7-cm mass in the distal esophagus/proximal stomach. Biopsy of this mass showed an invasive signet ring cell carcinoma. The purpose of our study is to discuss the cytological features and the differential diagnosis of this unusual thyroid FNA case.

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13442号 / 論医博第2241号 / 新制||医||1054(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 羽賀 博典, 教授 藤田 恭之, 教授 伊藤 貴浩 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

Introducción: El cáncer de estómago, posee una de las más altas incidencias a nivel mundial. En el Perú, no existe un adecuado registro y reporte de casos, que permita una evaluación de los clásicos y nuevos factores descritos en la literatura, así como de factores propios del carcinoma. Objetivo: Determinar la asociación entre el desarrollo de metástasis en pacientes con adenocarcinoma gástrico y el patrón en anillo de sello. Materiales y Métodos: Ejecutamos un estudio de casos y controles en el Instituto Nacional de Enfermedades Neoplásicas (INEN) en pacientes con diagnóstico de cáncer de estómago. Se definió como caso, a todo paciente que desarrolló metástasis y como control, aquel paciente que no desarrolló metástasis, nuestra exposición de interés fue el tipo de adenocarcinoma. Resultados: Evaluamos 174 casos y 93 controles. La edad promedio en los casos y controles fue de 58,8 y 58,6, respectivamente. El 86,78% de casos y 61,29% de controles fueron diagnosticados en estadios avanzados. Además, se evidenció que los casos presentaron una mayor posibilidad 5,57 veces (IC95%: 1,76 – 17,62) de haber presentado los subtipos anillo de sello en conjunto con otros subtipos histológicos en comparación a los controles. Conclusiones: En pacientes con cáncer gástrico que desarrollaron metástasis, el hallazgo del patrón en anillo de sello no es un factor asociado al pronóstico negativo. Por el contrario, podemos afirmar que en las personas con cáncer gástrico que desarrollaron metástasis es probable que hayan presentado algún patrón histológico que haya co-existido con el subtipo adenocarcinoma en anillo de sello. / Background: Stomach cancer has one of the highest incidences worldwide. In Peru, there is no adequate record and report of cases, which allows an evaluation of the classic and new factors described in the literature, as well as factors typical of carcinoma. Objective: To determine the association between the development of metastasis in patients with gastric adenocarcinoma and the histopathological pattern in signet ring cell. Materials and Methods: We conducted a case-control study at the National Institute of Neoplastic Diseases (INEN) in patients diagnosed with stomach cancer. It was defined as case, to any patient who developed metastases and as a control, that patient who did not develop metastases, our exposure of interest was the type of adenocarcinoma. Results: We evaluated a total of 174 cases and 93 controls. The average age in cases and controls was 58.8 and 58.6, respectively. The majority of cases (86,78%) and controls (61,29%) were diagnosed in advanced stages (greater than 2). Likewise, it was evidenced that the cases presented a greater possibility 5.57 times (IC 95%: 1.76 - 17.62) of having presented the seal ring subtypes in conjunction with other histological subtypes compare to the controls. Conclusions: In patients with gastric cancer who developed metastases, the finding of the signet ring pattern is not a factor associated with the negative prognosis. On the contrary, we can affirm that in people with gastric cancer who developed metastases it is likely that they have presented some histological pattern that has co-existed with the adenocarcinoma subtype in the seal ring. / Tesis

京都大学 / 新制・論文博士 / 博士(医学) / 乙第13552号 / 論医博第2281号 / 新制||医||1067(附属図書館) / (主査)教授 武藤 学, 教授 小濱 和貴, 教授 佐藤 俊哉 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM