Oncocytic Papillary Thyroid Carcinoma and Oncocytic Poorly Differentiated Thyroid Carcinoma: Clinical Features, Uptake, and Response to Radioactive Iodine Therapy, and Outcome

Abstract

ObjectiveThe main objective of this study was to review the clinicopathologic characteristics and outcome of patients with oncocytic papillary thyroid carcinoma (PTC) and oncocytic poorly differentiated thyroid carcinoma (PDTC). The secondary objective was to evaluate the prevalence and outcomes of RAI use in this population.MethodsPatients with oncocytic PTC and PDTC who were treated at a quaternary cancer centre between 2002 and 2017 were retrospectively identified from an institutional database. All patients had an expert pathology review to ensure consistent reporting and definition. The cumulative incidence function was used to analyse locoregional failure (LRF) and distant metastasis (DM) rates. Univariable analysis (UVA) was used to assess clinical predictors of outcome.ResultsIn total, 263 patients were included (PTC [n=218], PDTC [n=45]) with a median follow up of 4.4 years (range: 0 = 26.7 years). Patients with oncocytic PTC had a 5/10-year incidence of LRF and DM, respectively, of 2.7%/5.6% and 3.4%/4.5%. On UVA, there was an increased risk of DM in PTC tumors with widely invasive growth (HR 17.1; p<0.001), extra-thyroidal extension (HR 24.95; p<0.001), angioinvasion (HR 32.58; p=0.002), focal dedifferentiation (HR 19.57, p<0.001), and focal hobnail cell change (HR 8.67, p=0.042). There was additionally an increased risk of DM seen in male PTC patients (HR 5.5, p=0.03).The use of RAI was more common in patients with larger tumors, angioinvasion, and widely invasive disease. RAI was also used in the management of DM and 43% of patients with oncocytic PTC had RAI-avid metastatic disease. Patients with oncocytic PDTC had a higher rate of 5/10-year incidence of LRF and DM (21.4%/45.4%; 11.4%/40.4%, respectively). Patients with extra-thyroidal extension had an increased risk of DM (HR 5.52, p=0.023) as did those with angioinvasion. Of the patients with oncocytic PDTC who received RAI for the treatment of DM, 40% had RAI-avid disease.ConclusionWe present a large homogenous cohort of patients with oncocytic PTC and PDTC, with consistent pathologic reporting and definition. Patients with oncocytic PTC have excellent clinical outcomes and similar risk factors for recurrence as their non-oncocytic counterparts (angioinvasion, large tumor size, extra-thyroidal extension, and focal dedifferentiation). Compared with oncocytic PTCs, the adverse biology of oncocytic PDTCs is supported with increased frequency of DM and lower uptake of RAI.

A patient with a rare co‐occurrence of papillary and follicular thyroid carcinomas

“…29 The prognosis of PTCs with HCs does not seem to be significantly different than their non-HC-containing counterparts. 30 Herrera et al analyzed 22 cases of oxyphilic PTC and compared them with differentiated PTC and oxyphilic FTC. After 10 years post-resection, the tumor recurrence and cause-specific mortality rates of oxyphilic FTC were 28% and 18%, insignificantly different from 28% and 17% seen with the oxyphilic PTC.…”

“…Therefore, HCCs have been named as a distinct neoplastic entity by the 2017 World Health Organization guidelines on Pathologic Classification of Thyroid Neoplasms 29 . The prognosis of PTCs with HCs does not seem to be significantly different than their non‐HC‐containing counterparts 30 . Herrera et al.…”

Oncocytic Cell Carcinoma of the Thyroid: A Case Report and an Overview of the Diagnosis, Treatment Modalities, and Prognosis

“…The unfavorable prognostic factors include advancing age, male sex, larger tumor size at diagnosis, extra-thyroid expansion, and advanced stage at diagnosis [ 16 , 17 ]. In a retrospective study of 263 patients by Lukovic J et al, both oncocytic papillary thyroid carcinoma and oncocytic poorly differentiated thyroid carcinoma had higher 5- and 10-year incidence of locoregional failure and distant metastasis with an even higher incidence in the later [ 18 ]. Another study by Gross M showed the involvement of cervical lymph nodes in 43.4% of the patients [ 19 ].…”

Papillary thyroid carcinoma post total thyroidectomy: a case report

“…Macroscopically, PTC is usually characterized by a solid form with white-gray colorization, varying size, infiltrative edges, encapsulated, and calcification presentation. 14 In addition, PTC has a papillary structure with oval and fibrovascular nucleus with groundglass nuclear feature. 15 The appearance of PTC located in the primary lobe was rare but palpation followed by FNA could be used to quickly diagnose the lesion.…”