Portfolio CT

Labrador Retriever Bella, 9 years

Labrador Retriever Bella, 9 years

Progressive swallowing problems, especially of larger items

Post-contrast sequence

Pre-contrast sequence

With kind permission Dr. G. Viefhues, Small Animal Clinic Ahlen

Diagnosis

Description

The atlanto-occipital and atlanto-axial junctions are surrounded by a cavitating, space occupying lesion which is hypoattenuating to the surrounding soft tissue. The density of the individual cavities is 11-13 HU (density of the neighboring muscles is approx. 80 HU). Another space occupying lesion is located ventral to the M. longus capitis and appears separate from the other masses. It is approx. 3.8cm long, 2.5cm high, 4.1cm wide and results in severe displacement of the pharyngeal roof so that the caudal nasopharynx is completely obliterated. The occipital and temporal bones as well as the atlas (C1) and cranial aspect of the axis (C2) including the dens show a large number of well circumscribed, lytic defects. The space occupying lesion extends into the right caudal cranial fossa which leads to mild displacement and compression of the cerebellar vermis. Brain stem and spinal cord at C1 and C2 are also compressed; mostly from ventral and the sides. Severe, heterogenous and foamy contrast enhancement of the compressing structures in the spinal canal is evident. The space occupying lesions do not contrast enhance.

CT diagnosis

  • Soft tissue neoplasia atlanto-occipital and atlanto-axial junction with bone destruction and compression of cerebellum, pons and spinal cord

Discussion

The changes are suggestive of a myxosarcoma. Differential diagnoses include all other soft tissue tumours; however, the extreme hypodensity of all masses is highly suggestive of a myxosarcoma. The tumor is most likely arising from the atlanto-occipital and atlanto-axial joints, which are continuous which each other. The described masses are therefore most likely connected and part of one tumor mass.

Outcome

Bella was euthanized. The histopathological report confirmed the diagnosis of myxosarcoma.

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Small Münsterländer Samson, 7 years

Small Münsterländer Samson, 7 years

For 4 weeks: swelling lateral to the L eye, no improvement on antibiotics and pain killers: trauma cannot be ruled out.

With kind permission Dr. G. Viefhues, Small Animal Clinic Ahlen

Diagnosis

Description

An approx. 3cm large, mineral dense mass with a granular appearance extends from the zygomatic process of the left maxilla to the zygomatic arch. The mass protrudes slightly into the orbital cavity and causes mild deformity of the globe. The underlying cortex has a slightly roughened surface and shows small, fine osteolytic regions. An extension of the mass into the bone marrow is not evident.

CT diagnosis

  • Bony mass left zygomatic arch

Discussion

The appearance of the tumor is typical for a multilobular tumor of the bone. Other names are osteochonrosarcoma and chondrosarcoma rodens.

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GSD Dexter, 8 weeks

GSD Dexter, 8 weeks

Mucohemorrhagic nasal discharge, painful swelling left maxilla

Images courtesy of Kleintierklinik Greven. Dres. Böhmer, Cordes, Möller and Wienker

Diagnosis

Description

Large expansile, cystic lesions are visible in the right maxilla surrounding the crowns of the unerupted permanent 4th premolar (PM4), as well as of the 1st and 2nd molar (M1 and M2). The oral part of the cortex is partially disrupted at the level of M1 and M2. No connection to the nasal cavity is visible. Large expansile, cystic lesions are also surrounding the unerupted permanent mandibular incisor teeth.

After contrast medium administration moderate, heterogenous contrast uptake is visible within the cystic lesion in the right maxilla and in the incisor part of both mandibles.

A severe reduction in the number of nasal turbinates is present in both nasal cavities. The remaining turbinates appear plump. Material isodense to soft tissue is present between the remaining turbinates. The nasopharyngeal meatus is narrowed and contains a moderate amount of material isodens to soft tissue, which circumferentially occupies approximately 60% of its diameter.

Severe enlargement of the mandibular and the medial retropharyngeal lymph nodes is present bilaterally (left > right).

Radiographic diagnoses

  • Expansile, osteolytic bone lesions associated with the crowns of the unerupted permanent teeth (P4, M1 and M2 right maxilla, incisor teeth both mandibles)
  • Bilateral reduction in nasal turbinates
  • Soft tissue material between remaining nasal turbinates
  • Lympahdenomegaly mandibular and medial retropharyngeal lymphnodes

Discussion

The changes are suggestive of dentigerous cysts. As differential diagnosis odontogenic keratocysts should be considered. However, odontogenic kertocysts are rare in dogs. Differentiation of the various odontogenic cysts required histopathology examination of the wall of the cysts.

The changes in the nasal cavity are suggestive of a congenital hypoplasia of the nasal conchae with secondary bacterial infection. As a differential diagnosis to a simple conchael hypoplasia a ciliary dyskinesia with or with situs inversus (Kartagener Syndrom) should be considered. A chronic bacterial rhinitis with secondary destruction of the nasal conchae is less likely due to the young age of the dog.

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Irish Wolfhound Bailey, 1 year

Irish Wolfhound Bailey, 1 year

Initially left sided, purulent nasal discharge, later bilateral nasal discharge

CT images from July 2014. At that time unilateral nasal discharge was present.

CT images from March 2015. This time bilateral nasal discharge was present.

Images courtesy of Kleintierklinik Greven. Dres. Böhmer, Cordes, Möller and Wienker

Diagnosis

Description

Severe reduction in size and number of the turbinates in both nasal cavities. Between the remaining turbinates a mild to moderate amount of soft tissue dense material is present. Within the left frontal sinus soft tissue dense material with a fluid level is present (images flipped horizontally, patient was placed in dorsal recumbency during image acquisition). The mucosal lining of the left frontal sinus is thickened. Findings are almost identical in both CT studies.

Radiographic diagnoses

  • Bilateral reduction in number and size of nasal turbinates
  • Soft tissue dense material between the turbinates
  • Sinusitis with fluid accumulation left frontal sinus

Discussion

Changes are compatible with rhinitis- bronchopneumonia syndrome of the Irish Wolfhound. The etiology is unclear. Immune mediated or primary ciliary defects are discussed. A hereditary background is assumed. Affected dogs show transient or persistent mucoid to mucopurulent nasal discharge of variable degree from birth . Concurrent bronchopneumonia can occur (most likely due to the ciliar dysfunction leading to an increased susceptibility for infection).

No progression of the changes is seen over the one year period. No granuloma is visible in the frontal sinus. The paranasal bones are unremarkable, showing no permeative osteolysis. Therefore a fungal rhinitis is less likely. In addition the dog is very young making a fungal rhinitis unlikely as well.

Recommendations

None.

Normal CT study nasal cavity

A reduction in the number of turbinates is not always related to a destructive rhinitis. Consider congenital hypoplasia predisposing the nasal cavity to infection, especially in young dogs.

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