Case summary

An 8-year-old neutered male indoor cat was presented for evaluation of a year-long history of swelling over the bridge of the nose that extended from the subcutaneous tissue of the right upper eyelid to the dorsum of the skull. Intermittent regression of the mass lesion was reported with antibiotic or corticosteroid therapy; however, progressive swelling, malaise and hiding behavior persisted. CT revealed an aggressive osteolytic mass lesion in the right and left nasal cavities and extending into the frontal sinuses. Rhinoscopy using a 2.8 mm rigid telescope revealed somewhat normal-appearing turbinates rostrally and ventrally on the left side, with turbinate destruction on the right. After obtaining a biopsy from the right side of the nasal cavity, thick material filling the entire nasal cavity was visible caudally and was extracted endoscopically from a rostral approach. Surgical biopsy of the dorsal nasal bridge resulted in protrusion of inspissated material from the incision site. Rhinoscopic exploration revealed that the material extended into both frontal sinuses. Following extensive debridement and medical therapy, marked resolution of facial asymmetry was achieved.

Relevance and novel information

Facial distortion is often considered suggestive of a neoplastic process; however, it can also be seen with fungal and mycobacterial infections, and, in this case, an inflammatory condition of unknown etiology. In this cat, aggressive intervention and debridement of necrotic debris resulted in substantial bony remodeling of the skull and return to normal activity levels.

A 3-year-old, 4.0 kg, female, spayed Silver Marten cross rabbit (Oryctolagus cuniculus) was presented for evaluation of a suspected recurring spindle cell sarcoma following primary excision by the referring veterinarian. Physical examination revealed a large subcutaneous mass on the left metatarsus and a fine needle aspirate revealed suspected neoplastic spindle cells. Hematologic evaluation was unremarkable and a computed tomography scan revealed invasion of the mass into skeletal muscles but showed no evidence of metastatic disease. An amputation was performed, after which the patient recovered uneventfully. However, the rabbit was found suddenly dead at time of discharge from unknown cause. Gross, histologic, and immunohistochemical evaluation was performed, which diagnosed a peripheral nerve sheath tumor. To the authors’ knowledge, this is the first detailed case report of a lagomorph peripheral nerve sheath tumor specifically confirmed with immunohistochemistry. Wide surgical excision is considered the treatment of choice and may be combined with radiation therapy. Further research is required to determine risk factors, the role of adjunctive therapy, as well as long-term prognoses for peripheral nerve sheath tumors in rabbits.

Objective

To report onset and progression of clinical signs of a neuroendocrine neoplasm (NEN) presumed metastatic to the choroid in a dog.

Animals studied

A 7.5-year-old female spayed German shepherd dog mix referred for advanced imaging and evaluation of a subretinal mass in the right eye.

Procedures

Procedures performed included general physical and ophthalmic examinations; ocular, orbital, and abdominal ultrasonography; thoracic radiographs; cranial magnetic resonance imaging; serologic testing for infectious agents; analysis of hematologic as well as serum and urine biochemical parameters; echocardiography; electrocardiography; cytologic assessment of lymph nodes; and histopathology and immunohistochemistry of the enucleated globe.

Results

Examination and imaging identified a pigmented mass within and expanding the superior choroid. Following enucleation, a choroidal NEN with tumor emboli in scleral blood vessels was diagnosed by histopathologic assessment and confirmed by immunohistochemical labelling. Despite extensive and repeated diagnostic testing over many months, a putative primary site was not identified until 19 months after the initial ocular signs were noted. At that time, a heart-base mass and congestive heart failure were highly suggestive of a chemodectoma.

Conclusion

This comprehensive report of a NEN presumed metastatic to the choroid in a dog suggests that ocular disease can be a very early and solitary sign of NEN in the dog.