Publication:

ETV6-NTRK3 gene fusion positive secretory carcinoma breast in a two year seven-month-old child with metastatic axillary lymph node: a case report and review of literature

Secretory breast carcinoma (SBC) is an exceptionally rare type of breast carcinoma, accounting for less than 0.15% of all breast cancers. Only few cases have been reported in literature and even less with axillary lymph node metastasis and there is emerging application of use of Sentinel Lymph node biopsy (SLNB) or Low axillary sampling to assess the nodal status. There is a lack of consensus regarding the exact management and the role of targeted therapy is evolving. We report a case of SBC in a 2 year 7-month-old child. The child presented with a painless mobile peri areolar lump with blood-stained nipple discharge. She underwent excision biopsy outside followed by wide excision of residual lump with Low axillary sampling of the axilla showing axillary lymph node metastasis in our Centre and was subjected to level III axillary clearance. The tumor showed positivity for Estrogen receptor (ER) and the characteristic translocation, t (12; 15) (p13; q25) that results in the expression of the ETV6-NTRK3 fusion gene. After careful analysis of the case in Multidisciplinary team meeting, the child was started on Tamoxifen due to ER positivity and was decided to avoid use of chemoradiotherapy considering the age and doubtful benefit. Later when the tumour turned out to be positive for the fusion gene, she was started on targeted therapy with Entrectinib. To our knowledge, this is the youngest case reported in literature. The increasing use of targeted agents has been an evolving trend in the management of SBC with successful treatment outcomes. After careful analysis of our case and available literature, we have come to a conclusion that the treatment of choice for SBC should be conservation surgery with SLNB or Low axillary sampling followed by hormonal treatment if hormone responsive and the use of targeted agents. There is no reliable data regarding the role of adjuvant chemotherapy in SBC. Regarding adjuvant Radiotherapy, though it has been used in adults, its use in children should be limited.