Case Study

CT – Extraaxial intracranial mass lesion and proliferative chronic otitis externa extending into the tympanic bulla in a 14 year old MN Beagle

This 14 year old MN Beagle dog presented with chronic otitis; history of seizures of 1 year duration

DX

Right-sided extraaxial intracranial mass lesion level with the frontal lobes: the findings are compatible with a meningioma, which is usually benign regarding its biological behavior. Severe left-sided polypoid proliferative chronic otitis externa with extension of the proliferative changes into the left tympanic bulla and peripheral soft tissue inflammatio

Image Interpretation

CT of the head – A right-sided intracranial extraaxial mass lesion of 2 x 1.5 x 1 cm size is seen
emerging form the cerebral falx in the frontal lobe region. The lesion is broadly
attached to the cerebral falx and skull base. There is a marked mass effect on the
surrounding brain parenchyma with cerebral midline shift to the left. Marked uniform
contrast enhancement with dural tails is noted within the mass.
The findings of the ablated right ear canal region are as expected. There is no evidence
of relevant ear canal or tympanic bulla inflammation at this point.
The left tympanic bulla is largely aerated with even and smooth bony wall. However,
the left ear canal reveals severe expansile & irregular centrifugal and cetntripetal wall
thickening with multifocal polypoid proliferations and metaplasia occupying the lumen
of the ear canal with extension of the proliferative changes into the mesotympanon.
The bony emergence of the ear canal is expanded. Inflammatory fat stranding is noted
surrounding the left ear canal.
Both the left and right submandibular lymph nodes present changes compatible with
mild chronic reactive hyperplasia with mineralization. The left medial retropharyngeal
lymph node reveals moderate reactive hyperplasia.

Outcome

The position of the mass lesion is unfavorable for surgical resection. However, radiation
treatment may be considered. Regarding the otitis external, there are no findings specific of neoplasia developed at this point. Yet,
biopsies should be obtained – depending on the further management oft he case and
owner’s will – as malignant transformation in general is possible. The right ear canal presents expected findings after TECA-BO procedure.
The lymph node changes are compatible with bilateral reactive lymphadenitis with
chronic changes of the submandibular lymph nodes and more acute and severe changes
of the left medial retropharyngeal lymph node.