Peroperative evaluation of parathyroid glands using fat stain on frozen sections. Advantages and limitations

The possible benefit of fat stain in the diagnosis of parathyroid disease was elucidated in this prospective study comprising 51 patients operated on for primary hyperparathyroidism. The histo-pathological diagnosis was adenoma in 39 patients and hyperplasia in 9 patients. In three patients only normal glands were examined. The majority of adenomas contained very small amounts of intracellular fat, while the rim of normal parathyroid adjacent to the adenoma and additional normal glands examined had abundant intracellular fat. In two cases was the adenoma diagnosis arrived at due to the examination of the fat stained sections. In four cases with diffuse chief cell hyperplasia did fat stain corroborate hyperfunction in one case, but not in the other three cases. Five cases of nodular hyperplasia were encountered. In one case did fat stain demonstrate areas with low intracellular fat indicating hyperfunction in all examined glands. In two cases hyperfunctioning areas were demonstrated in one gland only, while all other glands had abundant intracellular fat. In two cases of nodular hyperplasia all examined glands had abundant intracellular fat. The clinical judgement of the surgeon at the operation is of outmost importance for the successful treatment of hyperparathyroidism. Fat stain facilitates a rapid identification of parathyroid tissue on frozen section and is of help in the diagnosis of adenoma. In the case of hyperplasia, however, the additional information given by fat stain is questionable. A normal appearance in one examined gland does not preclude abnormality in another. The present results do not support an altered surgical strategy with limited neck exploration.