Hobnail cells in encapsulated papillary thyroid carcinoma: Report of 2 cases with immunohistochemical and molecular findings and literature analysis

Authors

Shweta Agarwal, Department of Pathology, University of New Mexico, School of MedicineFollow
Qandeel Sadiq, Department of Pathology, University of Tennessee Health Sciences Center (UTHSC), Memphis, TN, United StatesFollow
Ibrahim Ortanca, Department of Pathology, University of Tennessee Health Sciences Center (UTHSC), Memphis, TN, United StatesFollow

Document Type

Article

Publication Date

3-1-2020

Abstract

Papillary thyroid carcinoma (PTC) is the most common malignant tumor of the thyroid gland with most tumors behaving in an indolent fashion. However, morphologic variants have been described, such as tall cell, diffuse sclerosing, columnar cell etc. which are biologically more aggressive. One of these variants includes the more recently described hobnail variant (HVPTC) which shows micropapillae and presence of large cells with apically placed hyperchromatic nuclei, reverse polarity, and eosinophilic cytoplasm, akin to hobnail cells. The presence of >30% hobnail cells in a PTC deserves categorization as a hobnail variant. This variant is usually associated with extra thyroidal extension, lymphovascular invasion and lymph node metastasis. We describe the pathologic and molecular features of two cases of encapsulated PTC with hobnail cells in a 68 year old male and a 22 year old female (30% and 10% hobnail cells respectively). Both cases presented as low stage (pT2) tumors and showed no aggressive features like lymph node metastasis, or extrathyroidal extension (ETE) at the time of presentation. Tumors in both cases showed presence of BRAFV600E mutation, absence of RAS and/or TP53 mutations, and were negative for RET and PAX88/PPARG gene rearrangements.

Recommended Citation

Agarwal S, Sadiq Q, Ortanca I. Hobnail cells in encapsulated papillary thyroid carcinoma: Report of 2 cases with immunohistochemical and molecular findings and literature analysis. Pathol Res Pract. 2020 Mar;216(3):152678. doi: 10.1016/j.prp.2019.152678. Epub 2019 Sep 30. PMID: 31740230.