Papillary thyroid carcinoma tall cell variant

Papillary carcinoma tall cell variant (TCV): a review

Tall cell variant of papillary thyroid carcinoma is an aggressive form of thyroid cancer with a significant mortality. This review describes the pathology of this variant, compares it to its pathologic mimics and discusses its clinical pathologic features. The literature on this tumor is reviewed. A brief discussion of molecular pathologic correlates is included.

Oncocytes, oxyphils, Hürthle, and Askanazy cells: morphological and molecular features of oncocytic thyroid nodules

Our understanding of oncocytic change in thyroid nodules is evaluated in light of the recent progress in understanding the mitochondrial DNA, its mutations, and somatic mutations that affect mitochondrial function. These changes are largely unrelated to the genetic events that result in proliferation and neoplastic transformation of thyroid follicular epithelial cells. The criteria for diagnosing lesions that are composed predominantly of oncocytic cells are the same as those applied to follicular lesions that do not contain oncocytic cells, including follicular variant papillary carcinomas, based on nuclear morphology, immunohistochemical profiles, and molecular markers.

Papillary carcinoma of the breast lacks evidence of RET rearrangements despite morphological similarities to papillary thyroid carcinoma

Rare breast neoplasms resembling the tall-cell variant of papillary thyroid carcinoma have been reported. In addition, papillary carcinoma of the breast occasionally displays nuclear features reminiscent of papillary thyroid carcinoma. In this study, we evaluated 33 intraductal/intracystic papillary carcinomas of the breast for the presence and extent of nuclear overlap, grooves, clearing, and inclusions, as well as features of the tall-cell or columnar-cell variants of papillary thyroid carcinoma. RET rearrangements were assessed in a subset of these cases. Paired probes localizing to the centromeric and telomeric ends of the RET gene on chromosome 10 were used for FISH using a break-apart approach. Single round and nested PCR was performed to detect RET/PTC1, RET/PTC2, RET/PTC3 and ELKS-RET fusion transcripts. Nuclear overlap, grooves, stratification, and clearing were identified in 24 (73%), 14 (42%), 11 (33%), and 9 (27%) cases respectively, whereas nuclear inclusions and 'tall-cell' features were each seen in only one (3%) and two (6%) cases, respectively. Four of 19 tested cases displayed split FISH signals in a low percentage of cells and were considered borderline for RET rearrangement. All 19 tested cases with amplifiable RNA were negative for the four RET fusion transcripts evaluated by RT-PCR. Although papillary carcinomas of breast often display one or more cytoarchitectural features of papillary thyroid carcinoma, there is no evidence that RET rearrangements are involved.