Case report:
A 52-year-old female presented with a painless right breast lump for one
week. On local examination of the breast, the mass measured 6 cm x 4 cm
and was located at 12 o’clock position. The overlying skin and
nipple-areolar complex were unremarkable. Axillary lymph nodes were not
palpable. Initially, the patient was evaluated with a mammogram which
showed a lobulated dense mass measuring 49 mm x 48 mm situated in the
upper inner quadrant of the right breast (BI-RADS category 4a). Further
evaluation with fine-needle aspiration cytology (FNAC) was suggestive of
ductal carcinoma. Computed tomography (CT) scan of the chest showed
heterogeneously enhancing mass measuring 4.4 cm x 4.3 cm in the upper
inner quadrant of the right breast with surrounding perilesional fat
stranding and few right axillary lymph nodes with maintained fatty hilum
but thick eccentric cortex-likely to be metastatic. (Figure 1)
A diagnosis of ductal carcinoma was made on histopathological evaluation
of USG guided tru-cut biopsy. The patient underwent right breast
mastectomy with frozen section examination of right axillary sentinel
lymph nodes. On frozen section examination, four lymph nodes identified
were uninvolved by carcinoma. Gross examination revealed a unifocal
tumor located in the upper inner quadrant with the greatest dimension of
4 cm. Histopathological examination revealed tumor cells arranged in
diffuse sheets and pseudorosettes. These tumor cells have round to oval
nuclei, powdery chromatin with scant cytoplasm. Mitosis and areas of
necrosis were noted (Figure2). Further, immunohistochemistry showed
tumor cells positive for cytokeratin (CK), focally positive for
insulinoma-associated protein 1(INSM-1), cluster of differentiation 56
(CD56), and negative for transcription factor GATA3, estrogen receptor
(ER), progesterone receptor (PR), human epidermal growth
factor receptor 2 (Her2 Neu) with nuclear protein (Ki67) proliferation
of about 40% (Fig. 3).
Based on cumulative information obtained from all the diagnostic
procedures including histopathology and immunohistochemistry, the final
diagnosis of invasive carcinoma with neuroendocrine differentiation was
considered. The pathological stage was pT2 (sn) N0. The postoperative
period was uneventful. The patient has received 4thcycle of chemotherapy with Carboplatin and Docetaxel 3 weekly (L1C4
completed) to date. USG of breast, chest X-ray, USG of abdomen and
pelvis, and the metabolic panel was performed at 4 months of follow up
which showed no evidence of recurrence of the disease.