Secondary hyperparathyroidism: Evidence for an association with papillary thyroid cancer

The association between primary hyperparathyroidism and nonmedullary thyroi d malignancies is well known. There is also, however, some evidence for an association between secondary hyperparathyroidism (SHPT) and thyroid cancer . We report three patients in whom invasive papillary thyroid carcinoma (PT C) was diagnosed before (one case) or at the time of (two cases) parathyroi dectomy for SHPT. Three women (ages 23, 54, and 64 years) presented with bo ne pain and pruritis typical of SHPT. All three patients had biopsy-proven parathyroid bone disease and elevated parathormone levels (664, 1674, and 2 051 pg/mL). All underwent subtotal parathyroidectomy and total thyroidectom y without complications. Pathology revealed diffuse parathyroid hyperplasia with multifocal invasive papillary thyroid carcinoma (two cases) and folli cular variant of papillary thyroid carcinoma tone case). Two cases were ass ociated with metastatic disease to local lymph nodes. The patients received adjuvant radioactive I-131, and remained tumor free 24 to 36 months after surgery with complete resolution of SHPT. We conclude: 1) PTC may accompany SHPT, 2) PTCs associated with SHPT may be locally aggressive although usua lly they are early tumors, 3) surgeons need to have an index of suspicion f or thyroid tumor when operating on patients with SHPT, and 4) routine remov al of the thymus as part of the operation for SHPT may have a secondary ben efit in diagnosing PTC in the occasional patient.