Magnifying colonoscopy was considered to be useful in determining the indications for colonoscopic removal.

This report examines the charcteristics of 10 patients surgically treated for unequivocal parathyroid carcinoma. Seven cases were from our series of 165 patients with primary hyperparathyroidism. Routine determination of serum calcium level by an automated analyzer occasionally led to early tumor detection. A spectrum of clinical and pathological variation was evident in our series. One of 3 patients with simple tumor resection and 1 of 4 patients with wide local excision in the initial operation showed local recurrence. Regional lymph node metastases without local recurrence occurred in another patient 3 years after the initial wide local resection and he was treated by neck and mediastinal dissections.Three additional parathyroid carcinoma patients with simple tumor resection were referred to us from elsewhere for recurrent hypercalcemia. Aggressive surgical resections of locally recurrent tumors or metastatic nodules brought marked alleviation of hypercalcemic symptoms, although none was curative.Although the prognosis of parathyroid carcinoma greatly depends on the biological malignancy of the tumor in individual cases, our ongoing data confirm the importance of thorough identification and en bloc removal of the tumor at the time of the initial operation. A neck dissection is necessary when there is evidence of lymph node metastasis.Parathyroid carcinoma is a relatively rare disease in Western countries [1][2][3]. In Japan its frequency is rather high at about 5% of primary hyperparathyroidism. Unfortunately, the diagnosis of para-

Malignant change has not been observed after total or subtotal excision of choledochal cysts in this series.