Variante células altas de cáncer papilar de tiroides: reporte de casos / Tall cell variant of papillary thyroid cancer: case report

El cáncer papilar constituye aproximadamente el 80% de todos los casos de cáncer de tiroides y el 85% de los tumores diferenciados. La variante de células altas representa el 1,3 al 12% del cáncer papilar siendo la variante agresiva más común de estos tumores. Posee un comportamiento agresivo, con mayor incidencia de invasión extratiroidea, linfovascular y metástasis a distancia, responsables de tasas de recurrencia más altas y peor pronóstico. Los casos aquí reportados reflejan las características que hacen sospechar mayor agresividad tumoral, desde el diagnóstico. Describimos dos pacientes de sexo femenino, entre 40 y 50 años, con historia de corta evolución, cuya presentación fue con síntomas de compresión locorregional y adenopatías metastásicas en cuello. Con hallazgos ecográficos e intraoperatorios de relevancia en cuanto la agresividad tumoral que hicieron sospechar la presencia de una variante agresiva del cáncer papilar. La histopatología de la variante de células altas posee una base molecular diferente respecto al papilar clásico que le confiere mayor morbi-mortalidad, constituyendo un factor de pronóstico independiente para la recurrencia. El tratamiento quirúrgico es la tiroidectomía total con vaciamiento profiláctico de los ganglios linfáticos centrales y eventualmente vaciamiento lateral de cuello según valoración preoperatoria, con posterior ablación postoperatoria de restos tiroideos mediante yodo radiactivo.

Papillary cancer constitutes approximately 80% of all thyroid cancer cases and 85% of differentiated tumors. The tall cell variant represents 1.3 to 12% of papillary cancers, being the most common aggressive variant of these tumors. It has an aggressive behavior, showing a higher incidence of extrathyroid and lymphovascular invasion and distant metastasis, responsible for higher recurrence rates and a worse prognosis. The cases reported here reflect characteristics that make us suspect tumor aggressiveness. These are female patients, between 40 and 70 years old, with a history of short evolution. They present locoregional symptoms or metastatic adenopathies, with ultrasound and intraoperative findings of relevance in terms of tumor aggressiveness that led to the suspicion of the presence of an aggressive variant of papillary cancer. The histopathology of the tall cell variant has a different molecular basis that confers its own morbidity and mortality, being an independent prognostic factor for recurrence. Total thyroidectomy is recommended with prophylactic dissection of the central lymph nodes and eventually lateral neck dissection according to preoperative evaluation followed by postoperative ablation with radioactive iodine.

Prognostic Significance of the Tall Cell Variant of Papillary Thyroid Carcinoma: Expression of p53, bcl-2 & Leu-M1 proteins

Papillary carcinoma of the thyroid is a well differentiated neoplasm and usually has a good prognosis. However, a subset of morphologically distinct papillary carcinoma has bad prognoses. The tall cell variant of papillary carcinoma (TCPC), characterized by tall columnar cells with a height at least twice the width, is the one of these. In order to differentiate TCPC from usual papillary carcinoma (UPC) in terms of prognosis, we performed immunohistochemical studies for the expression of p53, bcl-2 and Leu-M1 proteins in 25 cases of TCPC, 26 cases of UPC and 14 cases of poorly differentiated, solid type papillary carcinoma (SPC) with an analysis of clinical parameters. The nuclear expression of p53 was noted in one case each of UPC and TCPC. The cytoplasmic p53 expression of TCPC, UPC, and SPC was observed in 17/25 cases (68%), 14/26 cases (54%), 3/14 cases (21%), respectively. bcl-2 expression was 19/25 cases (76%), 18/26 cases (69%), 5/14 cases (36%), and that of Leu-M1 was 21/25 cases (84%), 18/26 cases (69%), 4/14 cases(29%), respectively. There were no statistical significance in the expression of those immunoproteins among these three groups (p>0.05). The p53 protein was consistently expressed in the cytoplasm rather than nucleus in this study and was very well correlated to bcl-2 positivity (p0.05). In conclusion, TCPC can not be separated from UPC as a distinct entity in this study and the cytoplasmic expression of p53 protein provides another mechanism of p53 inactivation in tumorigenesis of the thyroid papillary carcinoma, possibly by bcl-2 related mechanism.