BackgroundBreast carcinoma with osteoclast-like giant cells (OGCs) is infrequent, being most reported cased described as ductal invasive carcinomas. Invasive pleomorphic lobular carcinoma (PLC) is a distinct morphological variant of invasive lobular carcinoma characterized by higher nuclear atypia and pleomorphism than the classical type. In the best of our knowledge, a PLC with OGCs has not been previously reported.Case presentationWe report the case of a 72-year-old woman presenting with a pleomorphic tumor of the left breast with a dense infiltration by OGCs and T lymphocytes with a 10:1 predominance of CD8+ over CD4+ cells. The diagnosis of a lymphoid or mesenchymal neoplasia was excluded after demonstrating keratin expression by the neoplastic cells. The absence of E-cadherin expression and the morphological features were consistent with the diagnosis PLC with OGCs. In addition, we demonstrated the deleterious mutation C.del866C in CDH1gene, but no mutations in any of the other 33 genes analyzed by next generation sequencing.ConclusionsBreast carcinoma with stromal osteoclast-like giant cells is a very rare tumor, for that reason, the use of the cytologic features and growth patterns in combination with immunohistochemically studies is mandatory for a correct diagnosis of lobular carcinoma. In addition, further studies are necessary to clarify the influence of OGCs in the prognosis of these patients.Electronic supplementary materialThe online version of this article (10.1186/s13000-018-0744-6) contains supplementary material, which is available to authorized users.

Mammary hamartoma is a rare nonmalignant lesion. Only 11 cases of carcinoma associated with hamartoma have been previously described in the literature. We describe a case of infiltrating ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS) associated with hamartoma in a 35-year-old woman. Mammography showed the features of a typical hamartoma with suspicious microcalcifications arising in it. The patient underwent a radical modified mastectomy. It is likely that hamartoma is a coincidental finding. The identification of suspicious microcalcifications in a typical mammographic image of a hamartoma should prompt continued examination to exclude an underlying tumor.

For many years, mammary hamartoma was considered to be an under-diagnosed disease. However, with the increasing use of diagnostic procedures in breast tumors (mammography, ultrasound, fine needle aspiration cytology and core needle biopsy), diagnosis of this entity has increased. Mammary hamartomas normally manifest as painless, mobile, palpable lumps without adherence to skin or muscle. Mammography shows well-circumscribed tumors, separated from adjacent normal breast tissue. Macroscopically they are well-defined tumors, consisting of benign mammary glandular tissue, fibrous stroma and fat in variable proportions, sometimes with a pseudoencapulation. Because of the lack of cytological and architectural specificity of hamartomas, correlation between clinical manifestations, imaging techniques and histology is essential. This report describes a case of an 11-cm mammary hamartoma in a 46-year-old woman.

Secretory breast carcinoma is a rare neoplasm, histologically well-characterized, and secondary to ETV6-NTRK3 gene fusion, whose cytological features are scarcely described in the literature. We report the case of a woman with a history of secretory breast carcinoma 8 years before, who presented a periareolar nodule.A recurrence was diagnosed by fine-needle aspiration based on the cytomorphological features and pan-TRK immunocytochemistry on the cell block, and the patient underwent a mastectomy. The histology and molecular studies performed on the surgical specimen (immunohistochemistry, FISH and NGS) confirmed the diagnosis. Cytological smears showed abundant epithelial cellularity, in groups and single cells. These cells showed moderate atypia, with abundant cytoplasm. We observed intracytoplasmic inclusions and extracellular metachromatic globules. Immunocytochemical and immunohistochemical studies showed a triple negative breast tumour. NTRK overexpression was demonstrated with immunocytochemistry against pan-TRK on the cell block, as well as with immunohistochemistry in the surgical specimen. NTRK3 rearrangement was proved by FISH. In the primary tumour and in the recurrence, we demonstrated ETV6-NTRK3 fusion by NGS. After conducting a literature review, we have found 26 articles describing the cytological features of secretory breast carcinoma in 33 patients. The smears were described as groups of epithelial cells with vacuolated cytoplasm, single signet ring cells and a globular extracellular secretion.In only two cases molecular confirmation of the diagnosis with ETV6-NTRK3 fusion was proven, although not in the cytological specimen, but in the subsequent biopsy. The distinct cytological features of secretory breast carcinoma can help in its diagnosis, thus guiding the molecular studies. This is the first reported case that proves TRK overexpression, as a fusion surrogate, in the cytological sample.