Thyroid carcinomas with a variable insular component

Abstract

BACKGROUND. An insular growth pattern may be observed focally both in papillary and follicular thyroid carcinoma. The aim of the current study was to determine whether a greater extension of the insular component (IC) influences different clinical and histologic features at diagnosis, and a different tumor aggressiveness in terms of frequency in the occurrence of metastases as well as survival. METHODS. Thirty‐three patients with histopathologic findings consistent with IC were included in the study. IC was focal (<50% of the tumor area) in 16 patients and predominant (>50% of the tumor area) in 17 patients. These 2 groups were compared with a control group of 66 patients with differentiated thyroid carcinoma. RESULTS. At diagnosis, carcinomas with predominant IC differed from those with focal IC with regard to greater tumor size and a higher frequency of extrathyroidal extension and distant metastases. Patient follow‐up ranged from 5 to 188 months. The cumulative rate of distant metastases was significantly higher in patients with predominant IC. At the time of last follow‐up, carcinomas with predominant IC demonstrated a lesser frequency of disease‐free outcome (P = .002) and a higher number of tumor‐related deaths (P = .002), either when distant metastases were present (P = .03) or absent (P = .05) at the time of diagnosis. CONCLUSIONS. The presence of predominant IC is associated with a poor prognosis in terms of ongoing disease or death. Predominant IC should be considered a separate entity from not only the classical papillary or follicular carcinomas but also the focal IC tumor. Cancer 2007. © 2007 American Cancer Society.

Insular thyroid cancer

“…This result is noteworthy considering the higher rate of EBRT use in patients with distant metastasis compared with those assigned a lower disease stage. Although RAI uptake in ITC has been reported, there are conflicting data regarding the impact of radiation‐based therapy on the outcomes of patients with ITC 14, 19, 21, 22, 24, 38. Similar to our results, Rufini et al22 demonstrated improved outcomes for patients with ITC who received RAI treatment.…”

“…Although RAI uptake in ITC has been reported, there are conflicting data regarding the impact of radiation‐based therapy on the outcomes of patients with ITC 14, 19, 21, 22, 24, 38. Similar to our results, Rufini et al22 demonstrated improved outcomes for patients with ITC who received RAI treatment. In contrast, Pellegriti et al21 observed a clinical benefit from RAI in only 1 patient despite good RAI uptake in all 11 patients who had ITC with metastatic disease in their study.…”

“…The prognosis for patients with ITC appears to be better than that for patients with ATC 2, 9, 19. Given the relative paucity of data, there is no consensus about the prognostic relevance of ITC11, 20; indeed, there is debate about whether an insular histology is associated independently with prognosis 11, 12, 18, 20‐22…”

Well-differentiated Thyroid Cancer With a Minor Poorly Differentiated Component

“…Several papers agree with the evidence that CXCR4 expression is under the control of the RET/PTC-RAS-BRAF-ERK pathway in WDC (mainly PTCs), mediating an upregulation through BRAF activation and ending in inducing aggressive lymph node involvement. 34 Otherwise, a more typical vascular metastatic process in the PDs should be the final result of both CXCR4-SDF-1a downregulation and BRAF wild type. 16,21,22 The role of the molecular genotype has been largely studied in "pure" PD cancers, demonstrating that RAS, BRAF, RET/PTC or PAX8/PPRg show discordant results merely linked with worse prognosis in cases with high K-RAS expression.…”

Poorly Differentiated Thyroid Carcinoma: Diagnostic Features and Controversial Issues

“…In the WHO book, the "majority" of such growth patterns is mentioned as a requirement, although controversial conclusions have been reached by different groups that applied different thresholds, and some reports demonstrated that even minor STI components may affect prognosis [6,10,18,20]. Recently, a significantly different prognosis was observed using a 50% cutoff of STI areas [21]. In our experience, however, the vast majority of cases of PD thyroid carcinomas that meet the diagnostic criteria listed above display STI architecture as the predominant growth pattern, whereas cases with focal STI growth usually do not present high grade features nor follow an aggressive behavior.…”