RESUMO
Metastatic papillary thyroid carcinoma (PTC) without an identifiable primary tumor despite extensive microscopic examination of the thyroid gland is a rare but true phenomenon.We retrieved 7 of such cases and described in detail the clinical and pathologic features of these tumors. BRAF V600E immunohistochemistry and Sequenom molecular profile were conducted in selected cases. All patients harbored metastatic disease in the central (n=3), lateral (n=3), or both neck compartments (n=1). The histotype of the metastatic disease was PTC (n=5), poorly differentiated thyroid carcinoma in association with a PTC columnar variant (n=1), and anaplastic thyroid carcinoma in association with a PTC tall cell variant (n=1). Fibrosis was present in the thyroid of 5 patients. All patients with PTC were alive without evidence of recurrence. The 76-year-old patient with poorly differentiated thyroid carcinoma did not recur and died of unknown causes. Finally, the patient with anaplastic thyroid carcinoma was alive with distant metastasis at last follow-up. The median follow-up for this cohort was 2.2years (range, 0.8-17). BRAF V600E was detected in 4 of 6 cases by immunohistochemistry. In conclusion, metastatic nodal disease without identifiable thyroid primary is a rare but real phenomenon of unknown mechanisms. Although most tumors are low grade and well differentiated, aggressive behavior due to poorly differentiated or anaplastic carcinoma can happen. Most cases are BRAFV600E-positive thyroid tumors. A papillary carcinoma phenotype is found in all reported cases.
Assuntos
Carcinoma/secundário , Neoplasias Primárias Desconhecidas/patologia , Carcinoma Anaplásico da Tireoide/secundário , Neoplasias da Glândula Tireoide/patologia , Adulto , Idoso , Biomarcadores Tumorais/genética , Carcinoma/genética , Carcinoma/terapia , Carcinoma Papilar , Diferenciação Celular , Análise Mutacional de DNA , Feminino , Predisposição Genética para Doença , Humanos , Imuno-Histoquímica , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Mutação , Gradação de Tumores , Neoplasias Primárias Desconhecidas/genética , Neoplasias Primárias Desconhecidas/terapia , Fenótipo , Proteínas Proto-Oncogênicas B-raf/genética , Estudos Retrospectivos , Câncer Papilífero da Tireoide , Carcinoma Anaplásico da Tireoide/genética , Carcinoma Anaplásico da Tireoide/terapia , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/terapiaRESUMO
Myoepitheliomas have been described most commonly in salivary glands and have been reported elsewhere but are rare in the lung, with only six previously reported cases. To our knowledge, this represents the first endotracheal myoepithelioma. These tumors have characteristic features that distinguish them from other tumors, and the diagnosis is a pathologic one, based on the morphology and supported by immunohistochemistry. Myoepitheliomas should be considered in the diagnosis of any pulmonary nodule.
