Histology of Papillary Carcinomas - Other Findings

Occasionally, papillary carcinomas are grossly cystic – a change that can also be seen in the lymph node metastases. Over ninety per cent of papillary carcinomas, however, are non-encapsulated and discrete and vary in degree of local infiltration. On careful microscopy, other tumour foci may be found in both thyroid lobes; however, it is not possible to determine whether these are interstitial lymph-borne metastases or separate primaries including ‘harmless’ microcarcinomas.

See later: 
• Immunostaining of Papillary Carcinoma of the Thyroid
• Aetiological Factors in Thyroid Malignancy – Occult Papillary Microcarcinomas.