Long-Term Survival in a Dog After Adrenalectomy and Splenectomy for Two Different Malignancies with Portal Vein Involvement

TL;DR

A dog survived three years after successful surgery for two rare cancers involving a major blood vessel, which had not been previously reported in veterinary medicine.

Contribution

This is the first veterinary report of adrenal pheochromocytoma with portal vein involvement successfully managed by surgical removal.

Findings

The dog remained disease-free for three years after surgery without additional treatment.

Histopathology confirmed two distinct malignancies: adrenal pheochromocytoma and splenic B-cell lymphoma.

Surgical removal of the tumors and preservation of the portal vein was technically successful.

Abstract

Cancer is one of the most serious health problems in dogs, and occasionally, two different types of cancer can develop at the same time. This report describes a dog diagnosed with two separate tumors—one in the adrenal gland and another in the spleen. The adrenal tumor was closely attached to a major blood vessel (the portal vein), a condition that has not been previously reported in veterinary medicine. Despite the technical difficulty, the veterinary team successfully removed the adrenal gland, the spleen, and nearby lymph nodes while preserving the vessel. The dog recovered uneventfully and remained healthy for three years after surgery without additional treatment. This case illustrates that careful surgical planning and meticulous tumor removal can lead to long-term remission even in complex oncologic situations.

Concurrent occurrence of two independent primary malignancies in a single dog is rare and presents diagnostic and surgical challenges. A 9-year-old neutered male Cocker Spaniel was diagnosed with adrenal pheochromocytoma and splenic diffuse large B-cell lymphoma. Abdominal imaging revealed two distinct masses. Surgical management included adrenalectomy, splenectomy, mesenteric lymphadenectomy, and excision of a small mass adherent to the portal vein adventitia. Histopathology confirmed two separate malignancies, with chromogranin A positivity supporting pheochromocytoma and CD20 positivity confirming B-cell lymphoma. No additional metastatic lesions were identified, and the portal vein-associated mass was considered an isolated lesion closely adherent to the vessel wall, with its exact pathogenesis remaining uncertain. To the authors’ knowledge, this represents the first veterinary report describing adrenal pheochromocytoma with portal vein involvement successfully managed by surgical removal. The patient recovered well and remained disease-free for three years without adjuvant therapy. This case emphasizes that, even in technically demanding situations, meticulous surgical planning and comprehensive oncologic assessment can achieve durable remission and inform future approaches to complex veterinary cancers.

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