Poorly differentiated thyroid carcinoma in identical twins - a report of two cases and review of the literature

Sep 29, 2026

Uploaded by Mabel

Poorly differentiated thyroid carcinoma (PDTC) is described as a rare, aggressive thyroid malignancy, and its occurrence in monozygotic twins is exceptionally uncommon. Two monozygotic twin sisters developed discordant thyroid cancer subtypes despite identical genetics: Patient A presented with a 5.5 cm PDTC with invasion and distant metastases treated with thyroidectomy, lymphadenectomy, and radioactive iodine (RAI). Patient B developed recurrent papillary thyroid carcinoma managed with multiple surgeries and RAI. The discussion emphasizes heterogeneity, potential environmental or epigenetic contributions, and the diagnostic and therapeutic challenges of PDTC, suggesting advances in molecular profiling for improved management.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

Abstract

Introduction

Case presentation

Discussion

Conclusion

El Masri etal. Thyroid Research (2026) 19:1 Thyroid Research [https://doi.org/10.1186/s13044-025-00277-0](https://doi.org/10.1186/s13044-025-00277-0) CASE REPORT Open Access Poorly differentiated thyroid carcinoma in identical twins: a report of two cases and review of the literature Amal El Masri 1†, Celine El Moughrabi 1†, Anas El Zouhbi 1†, Anthony Shebly2, Hala Kassouf2,3, Mustafa Natout4, Yusef Hazimeh5 and Mustapha El Lakis 1,6* Abstract Background Poorly differentiated thyroid carcinoma (PDTC) is a rare, aggressive thyroid malignancy. While thyroid cancer has been reported in monozygotic twins, the occurrence of PDTC in this context is exceptionally uncommon. Such cases may offer unique insights into the interplay between genetic and environmental factors in thyroid cancer development. Case presentation We report the case of 67-year-old monozygotic twin sisters, both diagnosed with thyroid malignancies with discordant histology. Patient A presented with a 5.5 cm PDTC with local invasion and distant metastases. She underwent total thyroidectomy and lymphadenectomy followed by radioactive iodine (RAI) therapy. Patient B had a history of recurrent papillary thyroid carcinoma (PTC) over several years, managed with multiple surgeries and RAI. Despite their identical genetic background, the twins developed distinct thyroid cancer subtypes, with varying ages of onset and clinical courses. Discussion This case highlights the heterogeneous presentation of thyroid malignancies in genetically identical individuals, suggesting a potential role for environmental or epigenetic factors in tumorigenesis. A review of the literature on thyroid cancer in monozygotic twins indicates a general pattern of similar pathology and age at diagnosis, contrasting with the discordant phenotypes seen in our patients. PDTC poses diagnostic and therapeutic challenges due to its aggressive nature and limited response to conventional therapies. Advances in molecular profiling and targeted treatments may help improve management and outcomes. Conclusion The occurrence of discordant thyroid cancer subtypes in monozygotic twins is exceedingly rare and emphasizes the need for further studies exploring genetic and epigenetic contributions to thyroid cancer. Understanding these factors is critical for developing personalized approaches to diagnosis, treatment, and prevention. †Amal El Masri, Celine El Moughrabi and Anas El Zouhbi contributed equally to the study and are considered co-first authors. *Correspondence: Mustapha El Lakis [ml16@aub.edu.lb](ml16@aub.edu.lb) 1Faculty of Medicine, American University of Beirut, Beirut, Lebanon 2Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Beirut, Lebanon 3Department of Anatomy, Cell Biology and Physiological Sciences, American University of Beirut Faculty of Medicine, Beirut, Lebanon 4Department of Radiology, American University of Beirut Medical Center, Beirut, Lebanon 5Department of Endocrinology, American University of Beirut Medical Center, Beirut, Lebanon 6Department of Surgery, American University of Beirut Medical Center, Beirut, Lebanon © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended

FAQs

Why is PDTC in identical twins considered exceptionally rare?

PDTC is rare and aggressive, and documentation of PDTC occurring in monozygotic twins is described as exceptionally uncommon.

What cancers did each twin have, and how were they treated?

Patient A had PDTC with local invasion and distant metastases and underwent total thyroidectomy and lymphadenectomy followed by radioactive iodine (RAI). Patient B had recurrent papillary thyroid carcinoma over several years managed with multiple surgeries and RAI.

What does the case suggest about genetic versus environmental factors?

Despite identical genetic background, the twins developed distinct thyroid cancer subtypes, highlighting potential roles for environmental or epigenetic factors and the need for further studies.

Sep 29, 2026

Uploaded by Mabel