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Leiomyomatoid angiomatous neuroendocrine tumor (LANT) of the pituitary: a distinctive biphasic neoplasm with primitive secretory phenotype and smooth muscle-rich stroma

Vajtai, Istvan ; Sahli, Rahel ; Kappeler, Andreas ; Christ, Emanuel ; Seiler, Rolf

In: Acta Neuropathologica, 2006, vol. 111, no. 3, p. 278-283

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    Titel
    • Leiomyomatoid angiomatous neuroendocrine tumor (LANT) of the pituitary: a distinctive biphasic neoplasm with primitive secretory phenotype and smooth muscle-rich stroma
    Autor
    • Vajtai, Istvan. Institute of Pathology, University of Bern, Murtenstrasse 31, Postfach 62, 3010, Bern, Switzerland
    • Sahli, Rahel. Department of Endocrinology, University Hospital Bern, Bern, Switzerland
    • Kappeler, Andreas. Institute of Pathology, University of Bern, Murtenstrasse 31, Postfach 62, 3010, Bern, Switzerland
    • Christ, Emanuel. Department of Endocrinology, University Hospital Bern, Bern, Switzerland
    • Seiler, Rolf. Department of Neurosurgery, University Hospital Bern, Bern, Switzerland
    Dokumententyp
    • Postprint
    Sprache
    • Englisch
    Veröffentlicht in
    • Acta Neuropathologica, 2006, vol. 111, no. 3, p. 278-283. Springer-Verlag
    Andere elektronische Ausgabe
    OAI-PMH-ID
    • oai:doc.rero.ch:309849
    Summary
    We describe a hitherto undocumented variant of dimorphic pituitary neoplasm composed of an admixture of neurosecretory cells and profuse leiomyomatous stroma around intratumoral vessels. Radiologically perceived as a macroadenoma of 3.8cm in diameter, this pituitary mass developed in an otherwise healthy 43-year-old female. At the term of a yearlong history of amenorrhea and progressive bitemporal visual loss, subtotal resection was performed via transsphenoidal microsurgery. Discounting mild hyperprolactinemia, there was no evidence of excess hormone production. Histologically, solid sheets, nests and cords of epithelial-looking, yet cytokeratin-negative cells were seen growing in a richly vascularized stroma of spindle cells. While strong immunoreactivity for NCAM, Synaptophysin and Chromogranin-A was detected in the former, the latter showed both morphological and immunophenotypic hallmarks of smooth muscle, being positive for vimentin, muscle actin and smooth muscle actin. Architectural patterns varied from monomorphous stroma-dominant zones through biphasic neuroendocrine-leiomyomatous areas, to pseudopapillary fronds along vascular cores. Only endothelia were labeled with CD34. Staining for S100 protein and GFAP, characteristics of sustentacular cells, as well as bcl-2 and c-kit was absent. Except for α-subunit, anterior pituitary hormones tested negative in tumor cells, as did a panel of peripheral endocrine markers, including serotonin, somatostatin, calcitonin, parathormone and vasoactive intestinal polypeptide. Mitotic activity was absent and the MIB-1 labeling index low (1-2%). While assignment of this lesion to any established neoplastic entity is not forthcoming, we propose it is being considered as a low-grade neuroendocrine tumor possibly related to null cell adenoma