Thirteen cases of invasive solid papillary
breast carcinomas resembling the tall cell variant of papillary
thyroid neoplasms (
BPTC) are reported here. Some cases had long-term follow-up.
BPTC is a special type of primary
breast neoplasm showing a triple-negative profile but low aggressive potential. Knowledge on
BPTC is still scanty; therefore, the aim of the present paper was to report on the features of an additional 13 cases. All the patients were female individuals, and the mean age at presentation was 62.6 years; nodule sizes ranged from 0.6 to 2.5 cm (average, 1.6 cm). All the cases were characterized on histology by papillary, follicular as well as solid structures. The cells were columnar, eosinophilic mostly with granular cytoplasms, rich in mitochondria, with the features of oncocytes in no fewer than 7 cases.
Estrogen and
progesterone receptors as well as HER2 were consistently negative. The Ki67 proliferative index was low. Markers consistent with thyroid origin, such as TTF1 and
thyroglobulin, were negative. Five cases stained for mammoglobin and GATA 3 were positive. All cases proved to be invasive and 2 cases each experienced
metastases to 1 lymph node (axillary and intramammary). One case of the latter had a local recurrence. Nevertheless, all the patients are alive, free of disease 24 to 132 months after surgery, of which 8 are without further treatment The present series confirms that
BPTC is a primary
breast tumor of low malignant potential.