Cribriform-morular thyroid carcinoma with nodal metastasis: A diagnostic dilemma

Cribriform-morular thyroid carcinoma (CM-TC) is a rare thyroid malignancy typically affecting young females. It may be sporadic or associated with familial adenomatous polyposis (FAP). Previously considered a variant of papillary thyroid carcinoma (PTC), CM-TC is now recognized a distinct entity with uncertain histogenesis. CM-TC features characteristic cribriform and papillary morphology with squamoid morules and lacks colloid and psammoma bodies. It expresses TTF-1 and typically lacks thyroglobulin and PAX8 staining. Squamoid morules show positivity for CD10, bcl-2, E-cadherin, and CDX2 and are negative for p63/p40. It is characterized by nuclear and cytoplasmic beta catenin expression indicating activation of Wnt/beta-catenin signaling pathway. We present a case of cribriform morular thyroid carcinoma with nodal recurrence, initially misdiagnosed as tall cell PTC highlighting its diagnostic challenges and clinical relevance of accurate diagnosis.