Uncommon manifestation of a canine pheochromocytoma : a case report

A 9-year-old male neutered Golden Retriever was presented with a
history of acute onset deteriorating cervical pain. The dog was normal
on general physical and neurological examination. Magnetic Resonance
Imaging of the cervical spine revealed a focal, extramedullary,
infiltrative, poorly demarcated, heterogeneous mass with moderate
contrast enhancement at the level of the left cranial articular process
of the axis (C2), leading to an osteolysis and pathological fracture
of C2 as well as marked soft tissue trauma. Due to severe
ABSTRACT 337
findings and the grave prognosis, the dog was euthanized. At postmortem
examination, the right adrenal gland was severely enlarged
as a result of a neoplasm arising from the adrenal medulla. C2 was lytic
with surrounding musculature displaying a white, well-demarcated, tough
mass lesion. In addition, there were neoplastic growths in and adjacent to
the prostate and pulmonary lymph nodes. Based on gross, histologic and
immunohistochemical findings, a pheochromocytoma (PCC) originating
from the right adrenal gland was diagnosed which metastasized into the
cervical vertebral column, prostate and pulmonary lymph nodes. PCCs are
endocrine tumors derived from chromaffin cells, that can metastasize and
invasively infiltrate into the caudal vena cava. Depending on their potential
to produce catecholamines, they can also lead to cardiovascular, respiratory
and/or gastrointestinal clinical signs. In conclusion, this case report highlights
the variable manifestation of PCC regarding clinical signs and distribution
of metastases. PCC should be considered as a differential diagnosis for
cervical pain in elderly patients without other clinical signs for PCC.