Descripción de un caso: ¿es factible realizar una biopsia selectiva de ganglio centinela en tumores de mama originados en el tejido ectópico axilar?

Abstract

Breast cancer on axillary ectopic breast tissue is very rare, representing 0.3-0.6% of malignant breast cancers. Therefore, its early diagnosis is a real challenge. In this case, we describe a breast cancer on left axillary ectopic tissue in a 36-year-old female patient, who underwent local surgery with excision of the tissue. When approaching the nodal study of this patient, the possibility of selective study of the sentinel lymph node was considered. The absence of validated clinical guidelines in these cases and the exhaustive review of the literature led the multidisciplinary tumour committee of our hospital, the Hospital Clínico de Santiago de Compostela, to adopt the decision to attempt to perform this technique, adapting it, however, to this particular case. A double tracer was used, injecting technetium-99m in the periareolar area of the left breast and patent blue in the intratumoral area of the axillary ectopic tissue to determine whether both the breast and the tumour had the same lymphatic drainage pathways.

Finally, 7 sentinel nodes and 1 palpable non-sentinel node were detected, of which the first was marked with both technetium-99m and patent blue, 4 with the radioisotope only, and 2 stained with patent blue. Two macrometastases were detected intraoperatively in the sentinel nodes, stained only with patent blue, while the rest were negative. The tumour committee took the decision to treat the axilla with radiotherapy. It is therefore concluded that in these cases the periareolar lymphatic drainage and that of the tumour itself may be different, so it would be advisable to use the double tracer injected in different areas to correctly identify the sentinel lymph node. The literature available for this type of situation is scanty and there are no approved clinical guidelines to support our therapeutic decisions, so it would be essential to study breast cancer in infrequent locations, in depth, in order to achieve protocols standardised by international societies that would serve as a benchmark for the management of these cases.