EP-276 Tall Cell Carcinoma with Reverse Polarity (TCCRP) of the breast; a rare form of breast cancer

Abstract

Abstract Aim A case report on the diagnosis and treatment of this rare low grade triple negative breast cancer. Case Report A 41 year old female presented with a palpable left breast lump. Family history includes a sister with a rare myeloproliferative disorder. On examination, a left breast lower outer quadrant 2–3 cm hard irregular lump was palpable. Mammography and ultrasound revealed a 25 mm suspicious lesion (which was biopsied), with normal appearing lymph nodes. Results Biopsy revealed a grade 2 invasive apocrine carcinoma. Oestrogen and Herceptin receptors negative. Breast conserving surgery with sentinel lymph node biopsy was performed. Histology revealed a 22 mm well circumscribed tumour with nests of epithelial cells in micropapillary pattern with apocrine like appearance. The most striking feature was that the nuclei were at the apical rather than the basal poles of the epithelial cells (reverse polarity). No lymphovascular invasion present. Lymph nodes were negative (0/3). Diagnosis was then confirmed by molecular testing. Conclusion Tall cell carcinoma with reverse polarity (TCCRP)1, a rare cancer resembling tall cell variant of papillary thyroid carcinoma, was first reported by Eusebi et al in 20032. Although morphologically similar to metastatic papillary thyroid cancer, neither the immunohistochemical markers nor genetic profiles have established any connection3. Accurate diagnosis of TCCRP is important as it carries an excellent prognosis. Treatment is local regional radiotherapy. There is no indication for systemic therapy in this case, due to its indolent low metastatic potential.