Giant parathyroid adenoma: differential aspects compared to parathyroid carcinoma

Abstract

The 85% of cases of primary hyperparathyroidism (PHPT) are due to parathyroid adenomas (PA) and less than 1% to parathyroid carcinomas (PC). The PA usually measure <2 cm, weigh <1 g and generate a mild PHPT, whereas the PC usually exceeds these dimensions and are associated with a severe PHPT. However, giant PA (GPA), which is defined as those larger than 3 g, has been documented. Those may be associated with very high levels of PTH and calcium. In these cases, their differentiation before and after surgery with PC is very difficult. We present a case of severe PHPT associated with a large parathyroid lesion, and we discuss the differential aspects between the GPA and PC.Learning points:In parathyroid lesions larger than 2 cm, the differential diagnosis between GPA and PC should be considered.Pre and postsurgical differentiation between GPA and PC is difficult; however, there are clinical, analytical and radiographic characteristics that may be useful.The depth/width ratio larger or smaller than 1 seems to be the most discriminatory ultrasound parameter for the differential diagnosis.Loss of staining for parafibromin has a specificity of 99% for the diagnosis of PC.The simultaneous presence of several histological characteristics, according to the classification of Schantz and Castleman, is frequent in PC and rare in GPA.

A Giant Parathyroid Tumor during Pregnancy: Adenoma versus Carcinoma

“…GPA tends to be reddish to brown and soft in consistency, which we have observed in our case. Microscopically, carcinomas differ from adenomas mainly because of their trabecular arrangement, dense fibrous bands (present in 90% of the cases), spindle shape of the tumor cells, presence of frequent mitotic figures (in 81% cases), capsular invasion (in 67% cases), and blood vessel invasion (in 12% cases) [4]. In our case, trabeculation and dense fibrous bands are not appreciated.…”

“…GPA is considered when the tumor is larger than 3 grams. The suspicion of carcinoma is high if the tumor size is larger than 2 cm [4]. Diagnostic criteria in PA versus PC are not straightforward.…”

A Case of Hyperparathyroidism due to a Large Intrathyroid Parathyroid Adenoma with Recurrent Episodes of Acute Pancreatitis

“…Parathyroid adenomas usually measure less than 2 cm and weigh less than 1 g. In parathyroid lesions larger than 2 cm, the differential diagnosis between giant parathyroid adenomas and parathyroid carcinomas would be considered [ 11 ]. Parathyroid cysts or cystic adenomas often show large parathyroid ones [ 12 ].…”

Giant Parathyroid Adenoma versus Parathyroid Carcinoma: Differentiating Two Entities

“…Thus, it can be concluded that in patients with giant parathyroid tumours with significantly high serum calcium, in the absence of symptoms, the likely diagnosis is giant parathyroid adenoma rather than parathyroid cancer. 5 However, this subject requires further evaluation.…”