High Grade Differentiated Follicular Cell-Derived Thyroid Carcinoma Versus Poorly Differentiated Thyroid Carcinoma: A Clinicopathologic Analysis of 41 Cases

Abstract

HGDFCDTC show tumor necrosis, a median Ki-67 labelling index of 8.3%, with a high percentage (41%) of patients developing metastatic disease. PDTC presents slightly with large tumors, often in a background of multifocal tumors, with tumor necrosis nearly always seen, with a similar median Ki-67 labelling index of 6.9, with 29% of patients developing metastatic disease. Separation between groups is meaningful as early metastatic disease is relatively common, but mitotic counts/labelling indices are not different between the groups nor able to potentially risk stratify development of metastatic disease. It is hereby proposed to use ≥3 mitoses/2 mm 2 as the criterion for both tumor types, with/without tumor necrosis for the HGDFCDTC group and keep the PDTC criteria unchanged. Introduction:Follicular cell-derived carcinomas include differentiated, poorly differentiated, and undifferentiated (anaplastic) carcinomas (1-24). Histologic features (patterns of growth, presence of papillary thyroid carcinoma [PTC] nuclear features, convoluted nuclei, tumor necrosis, and an increased mitotic index) are applied in classi cation, although there is overlap between high grade differentiated follicular cell-derived thyroid carcinoma (HGDFCDTC) and poorly differentiated thyroid carcinoma (PDTC). Subjectivity is inherent in all classi cations and attempts at using more reproducible ndings to meaningfully risk stratify tumors into prognostically distinctive groups is helpful. To date, there has been no large, community practice-based evaluation of clinical and histological features, including Ki-67 immunohistochemistry labelling index, to suggest if meaningful separation between these entities can be achieved and shows distinctive management and outcome differences. This study will present clinical data, histologic ndings, Ki-67 labelling index, and patient management consequences in a retrospective review of 41 cases of high grade thyroid follicular cell-derived carcinomas.

The Long Journey towards Personalized Targeted Therapy in Poorly Differentiated Thyroid Carcinoma (PDTC): A Case Report and Systematic Review

“…Since cytological diagnosis of PDTC based on FNAC is challenging, our review has shown that some patients underwent a hemithyroidectomy or subtotal thyroidectomy with a completion thyroidectomy after histological diagnosis [ 38 , 44 , 52 , 54 , 59 , 65 , 69 , 85 , 103 , 104 , 107 , 108 , 115 , 117 ], but the majority of them were submitted to a total thyroidectomy as the initial operation [ 40 , 41 , 42 , 43 , 46 , 48 , 49 , 50 , 51 , 53 , 54 , 55 , 56 , 58 , 60 , 61 , 62 , 64 , 67 , 68 , 69 , 72 , 73 , 75 , 79 , 80 , 81 , 82 , 85 , 86 , 88 , 89 , 90 , 91 , 92 , 93 , 95 , 96 , 100 , 101 ,…”

“…Unlike in DTC [ 123 , 124 ], RAI appears to be relatively ineffective in the control of distant metastases in PDTC; thus, it is reasonable to consider the use of RAI for metastatic/advanced disease that demonstrates definite iodine uptake [ 125 , 126 ]. Likewise, most cases in our review received at least one cycle of RAI treatment, even without detectable metastatic foci [ 38 , 39 , 40 , 41 , 42 , 43 , 46 , 48 , 49 , 50 , 51 , 53 , 54 , 55 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 73 , 74 , 75 , 80 , 81 , 82 , 85 , 86 , 87 , 88 , 90 , 91 , 97 , 99 , 101 , 102 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 ...…”

“…In our case report, RAIR disease was evident after two RAI treatments. External beam radiation therapy (EBRT) is a viable option for controlling local disease in patients with PDTC and was utilized in the subset of patients with unresected, locally advanced disease or with metastatic foci such as bone lesions [ 42 , 49 , 50 , 58 , 60 , 61 , 62 , 63 , 64 , 67 , 68 , 69 , 70 , 74 , 75 , 80 , 81 , 85 , 90 , 91 , 97 , 98 , 102 , 106 , 107 , 108 , 109 , 112 , 113 , 116 ].…”

Clinical and Paraclinical Considerations Regarding ki67’s Role in the Management of Differentiated Thyroid Carcinoma—A Literature Review

“…Resta et al published a research study on 32 patients with DHGTC and reported an average value of the ki67 proliferation index of 5.6%, with a median of 3.5% (range 1-20%) in 22 cases [25]. Another study from Thompson et al reported ki67 proliferation index values calculated for DHGTC ranging from 2.3 to 19.6%, with a median of 8.3% and an average of 9.4% in their study performed on 41 subjects [26]. In their case study of DHGTC, Murata et al reported a ki67 proliferation index value of 10%, higher than the aforementioned value [27].…”

“…Harahap et al found that the ki67 expression and recurrence of thyroid cancer can be associated based on disease-free survival, which has a hazard ratio of 1.34 (1.13-1.92), and concluded that the ki67 proliferation index can be a predictor of thyroid cancer recurrence [15]. Thompson et al mentioned in their study that there was a trend to higher ki67 proliferation indices, suggesting metastatic disease development [26].…”