1/4. A case of spurious hypercalcitoninemia: a cautionary tale on the use of plasma calcitonin assays in the screening of patients with thyroid nodules for neoplasia.The measurement of plasma CT has an important role as a screening test for medullary thyroid carcinoma (MTC) in patients with thyroid nodules. However, elevated plasma CT levels should be interpreted within the context of the overall clinical picture in each individual case and carefully validated before therapeutic decisions are made. We present the case of a 17-yr-old girl who was referred to us with a thyroid nodule and elevated plasma CT levels, as measured by a one-site RIA not involving prior plasma extraction. plasma CT was re-measured using two different methods, a RIA with prior plasma extraction and a two-site immunochemiluminometric assay (ICMA), and was either very low or undetectable. Subsequently, samples were re-assayed using the initially applied CT RIA; plasma CT levels were again found to be elevated. These elevations were of a spurious nature, probably caused by the presence of an unidentified substance in the patient's plasma interfering with the measurement of CT in the initially used RIA. Our patient was eventually diagnosed with Hashimoto's thyroiditis, and had no evidence of MTC. As several conditions can cause either true or spurious hypercalcitoninemia, we suggest that elevated plasma CT levels should be confirmed at least once before other extensive diagnostic investigations are initiated or thyroidectomy is recommended. Finally, the assay selected should detect only the mature CT molecule.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
2/4. Metastatic bronchioloalveolar carcinoma presenting as a solitary thyroid nodule: report of a case with fine-needle aspiration cytopathology.Although cancers metastatic to the thyroid are frequently mentioned in autopsy studies, such a finding is quite rare in routine clinical practice. Metastatic non-small-cell carcinomas to the thyroid may present a diagnostic dilemma, particularly when they share morphological similarities with primary thyroid tumors. Herein, we report a case of metastatic bronchioloalveolar carcinoma that presented as an isolated left thyroid nodule in a 68-year-old woman. The aspirates were cellular and showed numerous papillary-like tissue fragments, elongated nuclei with prominent nuclear grooves, frequent mitoses, and psammoma bodies. The latter features raised the possibility of papillary thyroid carcinoma. However, also seen were three-dimensional tumor nests and acinar-forming fragments. Immunostains (positive for cytokeratin-7 and carcinoembryonic antigen and negative for cytokeratin-20 and thyroglobulin) confirmed the metastatic nature of the carcinoma. In a patient with known primary neoplasm, the differential diagnosis of a thyroid nodule should always include a metastatic lesion along with primary neoplasia.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
3/4. necrosis in thyroid nodules after fine needle aspiration biopsy. Report of two cases.Two cases of infarction of thyroid neoplasms following fine needle aspiration (FNA) biopsy are reported. Histologic study of a 2.5 x 2.5 cm nodule excised 18 days after FNA had diagnosed a Hurthle-cell neoplasm showed mainly necrotic debris and granulation tissue. While FNA made the diagnosis of a papillary carcinoma in the second case, which had had an FNA biopsy of the same nodule six years earlier, most of the nodule was fibrotic and necrotic. These two cases demonstrate the potential problems in such cases: (1) post-FNA infarction may obscure the nature of a cytologically diagnosed neoplasm, making histologic confirmation difficult, and (2) FNA of an infarcted nodule may have difficulties in obtaining diagnostic material, potentially resulting in a false-negative diagnosis. review of the literature on thyroid infarction shows it to be a rare event, with most reported cases occurring after FNA biopsy of a neoplasm. The finding of necrosis and fibrosis in an aspirate or surgical specimen should thus suggest the presence of a neoplasm.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |
4/4. Invasive cervical thymoma masquerading as a solitary thyroid nodule. Report of a case studied by fine needle aspiration.A 49-year-old woman underwent fine needle aspiration (FNA) biopsy of a presumed thyroid nodule. The initial cytopathologic interpretation suggested a chronic lymphocytic thyroiditis or a malignant lymphoma. The examination of frozen sections during surgery also suggested the presence of a lymphoma. However, histopathologic examination of permanent sections showed the lesion to be an invasive ectopic lymphocyte-predominant thymoma adjacent to the thyroid. Immunoperoxidase staining of FNA cell block sections and permanent sections showed positivity for keratin, proving the epithelial nature of the elongated and spindle-shaped tumor cells. This case high-lights the need to be aware of unusual lesions that may occur in the area of the thyroid; recognizing the potential diversity of "thyroid" masses that ultimately prove to be of nonthyroid origin should aid in making the correct cytologic differential diagnosis and interpretation of FNA samples obtained from such masses.- - - - - - - - - - ranking = 1keywords = nature (Clic here for more details about this article) |