Medullary carcinoma of the thyroid gland(MTC) constitutes approximatesly 3% to 10% of all malignant thyroid tumors. It appears in both familial and sporadic forms. Metastases are frequently present at diagnosis and are resistant to chemotherapy and radiotherapy. Surgical resection of the primary tumor and the metastases is the mainstay of treatment. Although MTC can be detected by elevated serum calcitonin, localization of residual or metastatic foci may be difficult. Many scintigraphic methods have been used for identification of the residual tumor or metastasis. However, most of them have either low sensitivity or low specificity. MTC frequently secretes somatostatin and may express somatostatin receptors. Recently, somatostatin-receptor imaging has been known to be useful for the detection of residual and recurrent medullary thyroid carcinoma. A 25 year-old woman who was dignosed as medullary carcinoma by biopsy of thyroid mass is presented. Thirteen years ago, she underwent left thyroidectomy due to thyroid cancer(MTC). Laboratory tests revealed an increase in the levels in serum CEA(CEA=557.6 ng/ml) and calcitonin(calcitonin= 720 pg/ml). The second patient, a 30 year-old female, complained of a palpable mass in the left anterior neck. Ten years ago, she underwent a right lobectomy of thyroid gland due to adenomatous goiter. Laboratory tests revealed an increase in the levels in serum CEA(CEA=617 ng/ml) and Calcitonin (Calcitonin=2,300 pg/ml). In both cases, pre- and postoperative In-111 pentetreotide scintigraphy were done and compared with "'I scintigraphy. In-111 pentetreotide scan may be useful for the localization of residual or metastatic medullary thyroid carcinoma. Further study is warranted to define the sensitivity and specificity of the technique.
Biopsy ; Calcitonin ; Carcinoma, Medullary ; Diagnosis ; Drug Therapy ; Female ; Goiter ; Humans ; Neck ; Neoplasm Metastasis ; Neoplasm, Residual ; Radionuclide Imaging ; Radiotherapy ; Receptors, Somatostatin ; Sensitivity and Specificity ; Somatostatin ; Thyroid Gland ; Thyroid Neoplasms ; Thyroidectomy

The early detection of recurrent differentiated thyroid carcinoma (DTC) cells in the post surgery DTC patients relies on the sensitivity of measuring both the level of thyroglobulin (Tg) and 131-Iodine distribution by Whole Body Scan (WBS). Undetectable level of Tg associated with negative WBS or elevated levels of Tg associated with positive WBS ("concordant") is ordinarily indicative of either absence or presence of disease. At times, elevated level of Tg with negative WBS or low levels of Tg with positive WBS ("discordant") could also occur. In the present study, we retrospectively reviewed series of 573 patients with DTC followed in the Diagnostic Imaging and Radiotherapy of the University "Federico II" of Naples between 1993 and 1997. We focused on 9 out of 573 patients (1.56%) who had a discordant pattern with low level of Tg/positive WBS in the post-surgical follow-up. Four patients were metastatic at presentation while 5 patients with metastasis during follow-up still remained in persistently low levels of Tg (<5 ng/mL). This result does point to some flaw in the evaluation of "discordant" cases. Reviewing data previously described series by resetting cut-off values of Tg <1 ng/ml as undetectable changed the apparent "discordant" subgroup of patients into "concordant". Recent introduction of recombinant human TSH (rhTSH) to enhance the expression level of Tg brought significant increase in the sensitivity of diagnostic evaluation of thyroid cancer patients. The role of burdensome WBS in the follow up evaluation of DTC patients is significantly reduced over time especially in low-risk patients while the relevance of Tg assay is steadily increased. Sensitive Tg assays, significantly improved our ability to assess disease status in follow-up of DTC. Given the possibility of late disease relapses, the need for long-term follow-up, and reduced delay in treatment of persistent disease, there is still need for greater sensitive diagnostic tools for DTC.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Biological Markers/blood ; Biomedical Technology ; Carcinoma/*diagnosis/drug therapy/radionuclide imaging ; Female ; Follow-Up Studies ; Humans ; Iodine Radioisotopes/diagnostic use ; Male ; Middle Aged ; Recombinant Proteins/diagnostic use ; Research Support, Non-U.S. Gov't ; Thyroglobulin/*blood ; Thyroid Neoplasms/*diagnosis/drug therapy/radionuclide imaging ; Thyrotropin/*diagnostic use ; Whole-Body Counting