Anaplastic thyroid carcinoma with rhabdoid phenotype: An unusual case and a comprehensive review. Issue 11 (9th June 2020)

• Record Type: Journal Article
• Authors: Bansal, Saloni; Sancheti, Sankalp; Kaur, Sukhjinder; Somal, Puneet; Kalra, Supreet Kaur; Sali, Akash Pramod
• Is Part Of: Diagnostic cytopathology. Volume 48:Issue 11(2020)
• Page Start: 1125
• Page End: 1130
• Publication Date: 2020-06-09
• Subjects: anaplastic thyroid carcinoma -- cytopathology -- fine‐needle aspiration cytology -- immunohistochemistry -- rhabdoid phenotype; Cytodiagnosis -- Periodicals; Pathology, Cellular -- Periodicals; Cytology -- Periodicals; 616.07582
• DOI: 10.1002/dc.24516
• Languages: English
• ISSNs: 8755-1039

Abstract

Abstract: Anaplastic thyroid carcinoma (ATC) is a highly aggressive thyroid malignancy predominantly affecting the elderly with a fatal outcome. ATC with rhabdoid phenotype is a rare variant, with only a few cases reported in the literature to date. We herein report a case of a 44‐year old female diagnosed as ATC with rhabdoid phenotype. She had a slow‐growing neck mass with no gross extrathyroidal extension (ETE) or nodal/distant metastasis at presentation. Computed tomography of the neck showed a well‐defined heterogeneously hypodense nodule in the right lobe of the thyroid. On cytology, a diagnosis of papillary thyroid carcinoma (PTC) with possible anaplastic transformation was made based on the presence of vague papillae with focal nuclear features of PTC and atypical pleomorphic/rhabdoid cells. The total thyroidectomy specimen showed a relatively circumscribed lesion with no gross ETE. Histopathological examination revealed sheets of rhabdoid cells with a focus of poorly differentiated thyroid carcinoma. On immunohistochemistry, rhabdoid cells were positive for AE1/AE3, focally positive for PAX8 and were negative for TTF‐1, synaptophysin, desmin, myogenin, S100P, and SMA. The neck lymph nodes were non‐metastatic. The patient was further treated with adjuvant radioactive iodine. Four‐months post‐operatively, the patient developed pulmonary metastasis which on biopsy examination revealed metastatic ATC. Apart from being a rare tumor type, this case is unusual with its presentation too; wherein, unlike described earlier in the literature the patient had a relatively mitigated clinical course with no gross ETE or nodal/distant metastatic disease. We also review the relevant literature along with this case.