Giant intrathyroid parathyroid adenoma: a preoperative and intraoperative diagnostic challenge.

We describe the case of an unusually large (giant) cystic intrathyroid parathyroid adenoma in a 73-year-old woman who had a 1-year history of hypercalcemia and a 5-year history of an asymptomatic enlargement of the left lobe of the thyroid. This unique case highlights the potential difficulties that can arise in the evaluation of thyroid nodules in patients with hyperparathyroidism. These difficulties were accentuated in this case by the large size of the mass, its intrathyroid location, and cytologic features that were compatible with a lesion of thyroid origin. In some cases, including this one, even a thorough preoperative evaluation that includes fine-needle aspiration biopsy and radiographic and nuclear medicine studies may not allow for a definitive preoperative diagnosis. The histologic overlap between thyroid and parathyroid lesions can also be problematic at the time of intraoperative frozen-section evaluation. Intraoperative parathyroid hormone monitoring may be helpful in these difficult cases.

Analysis of the molecular quality of human tissues: an experience from the Cooperative Human Tissue Network.

The scientific usefulness of the data obtained from tissue analysis is related to specimen quality, which may be affected by conditions that may contribute to the degradation of the specimen before processing and analysis. We determined the usability of nucleic acids extracted from banked human tissues for further molecular analyses. We assayed 151 tissue specimens, storedfor various times at 4 divisions of the Cooperative Human Tissue Network, National Cancer Institute, Bethesda, MD, for DNA and RNA degradation. Simple electrophoresis, polymerase chain reaction (PCR), reverse-transcriptase (RT)-PCR, and Northern blot analysis were compared to determine the optimal quality control procedure. In addition, a time course degradation procedure was performed on human lung tissue. Gel electrophoresis was as informative as PCR, RT-PCR, and Northern blot analysis in determining the molecular usefulness of the human tissues. Overall, 80% of the stored human tissues had good-quality DNA, and 60% had good-quality RNA. Electrophoresis procedures for DNA and RNA offer a quick and valuable measure of the molecular quality of stored human tissues. The DNA and RNA degradation of one tissue type (lung) was stable for both nucleic acids for up to 5 hours after excision.