Cribriform-Morular Thyroid Carcinoma Is a Distinct Thyroid Malignancy of Uncertain Cytogenesis

In this study, we reviewed the demographical, histopathological, and immunohistochemical features of the largest case series, consisting of 33 tumors. The age at time of pathological diagnosis ranged from 18 to 59 (mean 33) years, and all patients except one were female. Sixteen patients had multifocal and fifteen had unifocal disease. The status of focality was unavailable in two patients.  Tumors were well-circumscribed, ranging in size from 0.1 to 8.0 cm. The cribriform component was admixed with morulae in the majority, except seven had a cribriform-predominant architecture and two had predominantly solid growth. Variable degrees of nuclear enlargement, elongation, overlapping, a nd grooves were seen but florid nuclear convolution, intranuclear pseudoinclusions, and optically clear nuclei due to chromatin margination were not appreciated. There was no or little colloid material within the cribriform spaces. Two solid tumors had high-grade features. Immunohistochemical studie s showed beta-catenin nuclear and cytoplasmic positivity in all cases. The cribriform component was positive for TTF1 and negative for thyroglobulin. PAX8 was absent in half of these tumors and focal in the remainder. Morulae were positive for keratin 5 and CD5 and negative for p63, p40, TTF1, and P AX8. Molecular studies revealed germlineAPC mutations in 12 tumors and were negative in 5 sporadic tumors in a subset of tested tumors. Irrespective of the antibody used in this cohort, all cribriform-mo...
Source: Endocrine Pathology - Category: Pathology Source Type: research