Solid variant of papillary thyroid carcinoma: An analysis of 28 cases with current literature

The solid variant of papillary thyroid carcinoma: a multi‐institutional retrospective study

“…Third, the diagnostic criteria for PTC-SV in each individual study varied, ranging from 50% to 100% STI. [3][4][5][10][11][12][13]18 Therefore, data from a large-scale multiinstitutional study with meticulous pathology review to evaluate the actual percentage of STI and to exclude HGDTC, such as the current study, might provide more reliable data on the biologic behaviour of PTC-SV.…”

“…The few studies published to date have included a small number of cases, ranging from 5-30 patients. [2][3][4][5][6][7][8][9][10][11][12][13] While several studies, including a recent meta-analysis, suggest that PTC-SV is associated with a higher frequency of nodal metastasis and distant metastasis, decreased disease-free survival (DFS), and disease-specific survival (DSS), [2][3][4][5][6][7][8][9][10] others report a clinical outcome of PTC-SV comparable to that of -PTC classic type. [11][12][13] One plausible cause for this discrepancy is a lack of a consistent definition for PTC-SV across studies and major guidelines.…”

“…[2][3][4][5][6][7][8][9][10][11][12][13] While several studies, including a recent meta-analysis, suggest that PTC-SV is associated with a higher frequency of nodal metastasis and distant metastasis, decreased disease-free survival (DFS), and disease-specific survival (DSS), [2][3][4][5][6][7][8][9][10] others report a clinical outcome of PTC-SV comparable to that of -PTC classic type. [11][12][13] One plausible cause for this discrepancy is a lack of a consistent definition for PTC-SV across studies and major guidelines. The WHO classification 3rd edition defines PTC-SV as tumours "dominated by solid sheets", which many pathologists interpret as a requirement of >50% solid/trabecular/insular architecture (STI).…”

“…15 Further complicating the issue is the definition of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), which introduces another cutoff of STI, being 30% to exclude a NIFTP diagnosis. 16,17 Not surprisingly, the diagnostic criteria of PTC-SV vary, ranging from 50%, 3,5,12,13 70%, 4 75%, 10 80%, 18 to 100% 11 STI.…”

“…Several studies have included in the PTC-SV category tumours with a high mitotic count (≥5 per 10 high-power fields, HPFs) or tumour necrosis. 4,10,12 Such tumours fulfill the definition of HGDTC, a class of tumours that is known to follow a much more aggressive clinical course compared with PTC. 15,19,20 Aiming to clarify the prognostic impact of STI in PTC, we herein conducted a comprehensive clinicopathologic review in a large retrospective multi-institutional cohort of 156 patients with PTC containing STI.…”