PLoS ONE (Jan 2020)

Histopathology and immunohistochemistry as prognostic factors for poorly differentiated thyroid cancer in a series of Polish patients.

  • Agnieszka Walczyk,
  • Janusz Kopczyński,
  • Danuta Gąsior-Perczak,
  • Iwona Pałyga,
  • Artur Kowalik,
  • Magdalena Chrapek,
  • Maria Hejnold,
  • Stanisław Góźdź,
  • Aldona Kowalska

DOI
https://doi.org/10.1371/journal.pone.0229264
Journal volume & issue
Vol. 15, no. 2
p. e0229264

Abstract

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BACKGROUND:Poorly differentiated thyroid cancer (PDTC) is a rare but aggressive type of thyroid cancer (TC) and the main cause of death from non-anaplastic follicular cell-derived TC. Although the Turin criteria are well defined, the pathological features that could serve as diagnostic and prognostic factors remain controversial. MATERIALS AND METHODS:Forty-nine consecutive PDTC cases were identified in a single cancer center between 2000 and 2018. We analyzed the impact of routine histopathological and immunohistochemical features and several parameters that are not routinely included in pathology reports such as the presence of atypical mitoses, the amount of necrosis, or insulin-like growth factor-II mRNA-binding protein 3 immunostaining on the survival of patients with PDTC. Overall survival (OS) and disease-specific survival (DSS) were calculated using the Kaplan-Meier method. RESULTS:Of the 49 PDTC 34 (69.4%) showed the insular pattern of growth. The median of poorly differentiated area was 95% (range, 1-100), and 30 (61.2%) patients had a predominant (>50%) insular area. The 5-year OS and DSS rates at a median follow-up of 57 months were 60.6% and 64.3%, respectively. Univariate analysis showed that tumor size >4 cm, presence of atypical mitoses, Ki-67 >5%, and thyroglobulin (Tg)-negative immunostaining were associated with a higher risk of PDTC-related death. Atypical mitoses and Tg negativity were independent factors of worse DSS in multivariate analysis. Patients with insular and predominant insular areas showed a 3- and 6-fold higher risk of PDTC death when they displayed atypical mitoses. CONCLUSIONS:In PDTC, the presence of atypical mitoses may be helpful in identifying patients with poorer outcome and worth including in pathology reports, particularly in tumors with a dominant insular pattern of growth. Additionally, the inclusion of Tg immunostaining may be considered in a prognostic context, and not only as a diagnostic feature.