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Paraneoplastic immune‐mediated neutropenia in a dog following thymoma excision with later development of metastatic thymic carcinoma treated with toceranib phosphate
Author(s) -
O'Connell Erin,
Harper Aaron,
Blundell Richard,
Batchelor Daniel
Publication year - 2018
Publication title -
veterinary record case reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.165
H-Index - 4
ISSN - 2052-6121
DOI - 10.1136/vetreccr-2017-000548
Subject(s) - medicine , thymoma , thymic carcinoma , neutropenia , histopathology , pathology , mediastinum , thymectomy , median sternotomy , surgery , chemotherapy , myasthenia gravis
A thymoma was an incidental finding in a seven‐year‐old, female neutered, crossbred dog referred for an acute hepatopathy. Excision of the thymoma was performed via median sternotomy, and 11 weeks later the dog presented with severe neutropenia. The bone marrow was hypercellular, and paraneoplastic immune‐mediated neutropenia was diagnosed following exclusion of other causes. The neutrophil count increased to normal within seven days of treatment with prednisolone, which was subsequently tapered. A caudal mediastinal mass was documented 17 months following initial thymoma excision, and pleural and mediastinal metastases were evident on CT. Cytology was consistent with carcinoma. Following the prescription of toceranib phosphate, there was stable disease on CT at eight weeks and six months. At 12 months there was severe locoregional progression and the dog died nine days thereafter. Postmortem examination showed diffuse metastatic carcinoma of the caudal mediastinum, parietal pleura and diaphragm, and histopathology/immunohistochemistry was most consistent with thymic carcinoma.