Interesting breast tumours: A tripod of cases

Abstract

Knowledge regarding the lesser common breast tumours, including malignant papillary neoplasms and glycogen-rich clear cell carcinoma, is limited. Overall, cases of papillary carcinoma of the breast fare better than invasive
breast carcinoma, from the data available in literature. Glycogen-rich clear cell carcinoma is characterized by the
presence of clear cells, having mostly a poorer prognosis. We hereby present three such cases which would add to
the existing available information. Case 1 is a 79-year-old female who presented with a left breast lump and bloody
nipple discharge. Mammography suggested a malignant lesion, with FNAC suspicious of malignancy. Surgery was
done and histopathological examination showed irregular islands of tumour cells having papillary fronds with
absence of myoepithelial layer. Immunohistochemically, the tumour was GATA3, CK7, ER, PR positive, HER2
negative, with Ki67 index 10%. The case was diagnosed as Solid papillary carcinoma. Case 2 is a 57-year-old
female presenting with a left breast lump along with bloody nipple discharge. Mammography and FNAC were in
favour of malignancy. A trucut biopsy was done, and microscopy revealed a tumour having >90% papillary architecture
with an infiltrative pattern. Features were suggestive of Invasive breast carcinoma with papillaroid features. The
tumour was GATA3, CK7, ER, PR positive, HER2 negative, with Ki67 index 15%. Case 3 is a 70-year-old female
presenting with a right breast lump with nipple retraction. Mammography and FNAC were suggestive of
malignancy. Trucut biopsy followed by microscopy revealed polygonal tumour cells with clear cytoplasm in a nested
pattern, showing positive staining for Periodic Acid Schiff. Immunostaining showed GATA3 positive, PAX8
negative, ER and PR positive, HER2 negative, and Ki67 index 20%. A diagnosis of Invasive breast carcinoma with
Glycogen-rich clear cell pattern was made. Identifying these rare entities is important along with assessing
hormone status for avoiding overtreatment and undertreatment and applying appropriate targeted therapies.

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