5 research outputs found
A Neuroendocrine Carcinoma of Undetermined Origin in a Dog
In this report, we describe a case of neuroendocrine carcinoma of undetermined
origin in a dog. Necropsy revealed scattered small neoplastic nodules in the
bilateral lungs and a small nodule in the parapancreatic lymph node.
Histopathologically, both pulmonary and lymph nodal nodules showed a similar
histologic pattern, with neoplastic cells being arranged in diffusely
proliferating sheet-like cellular nests separated by variable amounts of fibrous
septa, sometimes forming rosettes and duct-like structures. Scattered small
necrotic foci and invasion to fibrous septa were typically observed. Neoplastic
cells showed round to oval-shaped nuclei with prominent nucleoli and abundant
eosinophilic cytoplasm that were positive for Grimelius’ silver impregnation
staining and immunostaining with cytokeratin, synaptophysin, vasoactive
intestinal peptide and chromogranin A, indicative of the development of a
neuroendocrine carcinoma. However, judging from the distribution of tumors
lacking the portion suggestive of the primary site in any organ examined, as
well as no further indication of differentiation potential of neoplastic cells,
this tumor has so far been diagnosed as neuroendocrine carcinoma of undetermined
origin