Clinicopathological Significance of Poorly Differentiated Thyroid Carcinoma

Abstract

The clinicopathological importance of a heterogeneous group of poorly differentiated thyroid carcinomas is not fully understood. Using data obtained from 303 surgically treated patients with differentiated thyroid carcinomas, the correlations between the aggressive histologic features and the clinicopathological findings, postoperative recurrences, and prognosis were retrospectively examined. In 201 cases, the carcinomas were well differentiated. The remaining 102 cases of poorly differentiated carcinomas were divided into two groups: focal-poorly differentiated (<10%) and diffuse-poorly differentiated (> or = 10%) carcinomas according to the extent of the poorly differentiated component. These poorly differentiated carcinomas were associated with high age (focal-poorly differentiated and diffuse-poorly differentiated versus well differentiated: 55 years and 59 versus 49; p < 0.0001), frequent presence of lymph node metastases (70% and 66% versus 48%; p = 0.0099) and distant metastases at diagnosis (11% and 11% versus 2%; p = 0.0098), and extrathyroidal invasion (53% and 53% versus 21%; p < 0.0001). There was independent correlation with age and the presence of extrathyroidal invasion. Cases of diffuse-poorly differentiated carcinomas showed frequent relapse (diffuse-poorly differentiated versus focal-poorly differentiated and well differentiated: 45% versus 30% and 24%; p = 0.0062) and poor prognoses (mean survival period = 9.15 versus 19.03 and 20.87 years; p < 0.0001) compared with the well and focal-poorly differentiated carcinomas. These data suggest that diffuse-poorly differentiated carcinoma is an important clinicopathological entity.

Association between prognostic factors and clinical outcome of well-differentiated thyroid carcinoma: A retrospective 10-year follow-up study

“…Similarly, young age was associated with favorable prognosis, consistent with a number of other studies (16,18,21). Previous studies demonstrated that patients with HTC or FTC were more likely to show unfavorable clinical outcomes compared with those suffering from PTC (22)(23)(24). Consistently, the present study found that patients suffering from HTC or FTC upon diagnosis were more susceptible to bone metastases.…”

Poorly Differentiated Follicular Thyroid Carcinoma with Rhabdoid Phenotype: A Clinicopathologic, Immunohistochemical and Electron Microscopic Study of Two Cases

“…Moreover, these carcinomas with insular pattern often show diffuse immunoreactivity for thyroglobulin, reflecting functional differentiation. Other investigators have emphasized cytologic features and include the tall-cell variant of papillary thyroid carcinoma in the poorly differentiated category, perhaps because of its aggressive clinical course (15,17). However, we believe that the height of the cell (tall cell) is not enough for this variant of papillary carcinoma to be considered poorly differentiated.…”

Poorly differentiated carcinoma of the thyroid: validation of the Turin proposal and analysis of IMP3 expression

“…Different terms have been used to refer to these tumors, including solid, 3 trabecular, 4 insular, 5,6 poorly differentiated, 3,7,8 …”