oncocytic papillary carcinoma

Digital case

 Thyroid papillary carcinoma with oncocytic features on Flickr by ddkri.

Oncocytic papillary carcinomas may have papillary or follicular architecture. The papillary type are characterised by complex branching papillae in which oncocytic cells cover thin fibrovascular stromal cores; the “Warthin-like” tumour has intense stromal infiltration by chronic inflammatory cells.

Oncocytic papillary carcinomas with follicular architecture may be macrofollicular or microfollicular with variable colloid storage.

In this setting, the colloid may be hypereosinophilic. They may be well delineated and even encapsulated, but careful evaluation usually identifies at least superficial infiltration of surrounding tissue. Some lesions are frankly and widely invasive.

The diagnosis of papillary differentiation is based on the nuclear features of these lesions. The oncocytic cells are usually polygonal but may be columnar; they have abundant granular, pale, eosinophilic cytoplasm.

The nuclei have variably developed atypia of papillary carcinoma, namely: enlargement, oval shape, elongation, and overlap, with clearing, resulting in a ground glass appearance, and irregular nuclear contours with nuclear pseudoinclusions and grooves.

It is important to identify these features in well delineated lesions with follicular architecture, because they may predict lymph node metastasis.

Open References

 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1770246/