Oncocytic (Hürthle Cell) Tumors of the Thyroid: Distinct Growth Patterns Compared with Clinicopathological Features

Abstract

Neoplastic growth results from cell production that exceeds cell loss. We registered mitotic and apoptotic indices (MI and AI) in 97 immunohistochemically verified oncocytic (Hürthle cell) tumors of the thyroid (OT; 50 adenomas [OA], 20 atypical adenomas [aOA], and 27 carcinomas [OC]) and compared these kinetic data with histological diagnoses and other parameters. MI, although very low in all, was significantly higher in carcinomas than in adenomas. Conversely, AI did not differ as much among the 3 groups. This indicates that the magnitude of cell deletion did not play a prominent role in determining the disparate growth of the 3 types of oncocytic tumors. Cluster analysis with MI and AI per case as variables revealed the existence of 3 groups of neoplasms with highly distinct growth characteristics: (1) near-steady state (n = 78, all diagnostic categories represented); (2) progressive (n = 9, mostly carcinomas); and (3) regressive (n = 10, mostly adenomas). MI distinguished between histologically benign and malignant with the greatest discriminant power of the variables tested. Proliferative indices should thus be included in the differential diagnostic evaluation of oncocytic thyroid tumors. Our study also suggests that invasiveness and growth are 2 diverging properties of carcinomas.

Prognostic factors of recurrence in encapsulated Hurthle cell carcinoma of the thyroid gland

“…Indeed, mitotic index was shown to be significantly higher in Hurthle cell carcinoma than in adenoma, and the Ki-67 proliferative rate was found to have a significant impact on the outcome in Hurthle cell tumors. 9,18 Capsular and vascular invasion are now accepted as the defining features of malignancy in follicular tumors. 1 However, controversy remains regarding their respective prognostic value.…”

CBX7 Expression in Oncocytic Thyroid Neoplastic Lesions (Hürthle Cell Adenomas and Carcinomas)

“…Lymph node metastasis frequently involves the regional lymph nodes, even though metastases usually occur hematogenously. The overall mortality rates range from 9 to 28% [11][12][13][14][15] .…”

Poorly differentiated oncocytic thyroid carcinoma – diagnostic implications and outcome

“…Consequently, oncocytic PDTC can be regarded as a variant of conventional PDTC 2 . However, this variant was explicitly excluded from the Turin criteria, although it has long been known that oncocytic thyroid tumours can have an adverse outcome 1,14,21,22 …”

“…2 However, this variant was explicitly excluded from the Turin criteria, although it has long been known that oncocytic thyroid tumours can have an adverse outcome. 1,14,21,22 It has not been established so far whether the Turin criteria for PDTC can be applied to oncocytic thyroid carcinomas and if, therefore, an oncocytic variant of PDTC can be diagnosed. If this is the case, then clinical outcome compared to conventional PDTC remains to be established.…”