PMC7652541_01
Breast metastases from pancreatic NET (FNA): Cytopathology could not give information about tumour biological features; the neoplastic elements are uniform and consist of small cells with scant cytoplasm, salt-and-pepper chromatin and micronucleoli and consistent neuroendocrine tumour (A and D: HE 40x; B: Papanicolau 40x; C: Giemsa 100x).
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However, considering the background of the existing metastatic NEN disease, fine needle aspiration (FNA) was repeated but was inconclusive, showing malignant tumour cells (Figure 2).
Breast metastases from pancreatic NET (inset: core biopsy). (A): nests of uniform cells with round nuclei; (B): with high proliferative index of 18% by Ki67; (C): immunohistochemistry for chromogranin A shows diffuse cytoplasmic reactivity in tumour cells and (D) on the other hand, only the lobular structures show positivity for CK7.
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A tru-cut biopsy was carried out which finally confirmed our suspicion of a metastasis from the well-differentiated endocrine carcinoma with a mitotic cell count (Ki67) of 18%, positive for CgA and synaptophysin (SYN), negative for CDX-2, ER/PgR and Her-2 (Figure 3).
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Metastatic breast NET from lung carcinoid. (A): Breast tissue infiltrated in lobular carcinoma fashion; (B): immunohistochemistry for CK7 and for synaptophysin; (C): diffuse cytoplasmic reactivity in tumour cells and (D) with typical pagetoid involvement of the hyperplastic duct.
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AC (Figure 4). A follow-up 68Ga-PET/DOTATOC, CT with contrast medium and MRI showed further lesions on left and right femur.
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