Papillary Thyroid Cancer-Aggressive Variants and Impact on Management: A Narrative Review

Abstract

Introduction: Aggressive variants of papillary thyroid cancer (PTC) have been described with increasing frequency. These variants include diffuse sclerosing variant, tall cell variant, columnar cell variant, solid variant, and hobnail variant.

Methods: We have performed a review of the more aggressive variants of PTC with respect to main characteristics, histological and molecular features, and the consequences that the knowledge of these variants should have in the treatment of the patients.

Results: At the present time, we do not know the prognostic value of these aggressive PTC variants. The extent of the surgical treatment and adjuvant therapy necessary should be decided on the basis of the extent of the tumor at presentation and the opinion of experienced clinicians.

Conclusion: These aggressive variants should be known by clinicians, to avoid underdiagnosis, and treated according to the latest recommendations in the literature.

Keywords: Aggressive variants papillary thyroid cancer; Columnar cell variant; Diffuse sclerosis variant; Hobnail variant; Solid variant; Tall cell variant.

Fig. 1

a Scanning view of thyroidectomy specimen affected with DSV of PTC classically showing the lack of mass-forming lesion. b Low power microscopic view (4 × 10) of DSV showing numerous psammoma bodies and tumor cells infiltrating throughout the thyroid parenchyma associated with fibrosis and chronic lymphocytic thyroiditis. c Low power microscopic view (4 × 10) of SV of PTC showing a trabecular and nested growth. d High power microscopic view (40 × 10) of SV showing diagnostic nuclear features of papillary thyroid carcinoma, including nuclear enlargement, chromatin clearing, overlapping, irregular nuclear membranes and grooves in the absence of diagnostic criteria for poorly differentiated thyroid carcinoma. e High power microscopic view of a solid variant of papillary thyroid carcinoma occurring in a 10-year-old Ukrainian boy exposed to the Chernobyl disaster. The tumor is composed of solid/nests (arrow)

Fig. 2

a Medium magnification view (20 × 10) of a TCV of PTC showing elongated follicles with parallel arrangement (“tram-track” appearance). b High magnification view (60 × 10) of TCV exhibiting tumor cells that are taller than wider (2:1 or 3:1 height to width ratio) with moderate to abundant light eosinophilic cytoplasm, distinct cell borders, and prominent nuclear features diagnostic of PTC. c Low power microscopic view (4 × 10) of CCV of PTC showing a highly cellular neoplastic proliferation. d High magnification view (40 × 10) of CCV exhibiting elongated tumor cells and hyperchromatic nuclei and prominent nuclear stratification, the cardinal feature of this variant. e Medium magnification view (20 × 10) of an HV of PTC showing complex papillary growth and micropapillary architecture. f High magnification view (60 × 10) of tumor cells with hobnail morphology characterized by pleomorphism, high nuclear to cytoplasmic ratio, apically or eccentrically placed nuclei, and surface bulging