CT of the feline oral cavity for squamous cell carcinoma staging

Why oral tumours in cats need cross-sectional staging

Squamous cell carcinoma (SCC) is the most common oral malignancy in cats, and it is highly locally invasive. In 20 cats treated by total glosso-mandibulectomy (Iwata et al., Veterinary and Comparative Oncology, 2025), the histopathological margin was the only factor associated with progression-free and overall survival on univariate analysis. Knowing how far the tumour extends before surgery or radiotherapy is therefore central to planning.

Not every oral mass is SCC. In 60 cats treated by maxillectomy for an oral tumour (Liptak et al., Veterinary and Comparative Oncology, 2021), 19 (31.7%) had benign tumours and 41 (68.3%) malignant ones. Imaging stages the mass, but histology names it.

What CT shows in feline oral SCC

In 18 cats with oral SCC (Gendler et al., Journal of the American Veterinary Medical Association, 2010), CT located the tumour in:

• the sublingual or lingual region (7 cats)
• the maxilla (5)
• the buccal mucosa (4) and mandible (4)
• the pharyngeal mucosa (2), soft palate (1) and lip (1)

Key findings:

CT finding	What the evidence shows
Osteolysis	Osteolytic mass lesions in 9 of 18 cats (Gendler et al.)
Orbital extension	The most common extension of maxillary masses (5 cats) (Gendler et al.)
Contrast enhancement	Heterogeneous enhancement was the most common pattern (8 of 18) (Gendler et al.)
Periosteal reaction	Maxillary SCC showed severe cortical destruction with irregular, “pumice stone-like” periosteal reaction (4 maxillary masses in a series of 10 cats) (Strohmayer et al., Frontiers in Veterinary Science, 2020)
Deep bone invasion	Marked, extensive and deep bone invasion on histology in most horses and cats in the same study (Strohmayer et al.)

CT and oral examination agreed on tumour location at every site except the soft palate, where CT identified 1 cat and oral examination 4. A careful oral examination under anaesthesia remains part of staging.

None of the quantitative CT features, including mass size, attenuation and lymph node width, was correlated with survival time. CT phenotypes were also unrelated to histological grade. CT describes extent; it does not grade or predict.

Lymph nodes and lungs

Regional spread is not rare. In 49 cats with advanced oral SCC assessed by mandibular lymph node cytology and three-view thoracic radiographs (Soltero-Rivera et al., Journal of Feline Medicine and Surgery, 2014):

• mandibular lymph node metastasis was present in 31% (15 of 49)
• possible thoracic metastasis was seen in 10% (5 of 49)
• of the nodal metastases, 8 came from maxillary, 4 from mandibular, 2 from sublingual and 1 from caudal pharyngeal tumours

The authors note that both rates were higher than most earlier reports. CT can show lymph node enlargement, but node size alone is not proof of metastasis. In a PET/CT study of 12 cats (Randall et al., Veterinary and Comparative Oncology, 2016), two of three cytologically confirmed metastases were equivocal on CT.

Where CT underestimates the tumour

CT is less reliable for soft-tissue infiltration than for bone:

• Soft-tissue infiltrative tumours that were subtle and ill defined on CT were highly visible and more extensive on FDG-PET/CT. Tumours invading bone were more similar in extent on both methods.
• In lingual and laryngeal SCC, most cats had a large region of high FDG uptake outside the CT tumour volume (Yoshikawa et al., Veterinary Radiology & Ultrasound, 2013).

Oral cavity CT protocol at a glance

Staging uses contrast-enhanced CT of the head, with the regional lymph nodes in the field, as in the CT study of 18 cats. When CT is performed under anaesthesia for the oral mass, including the thorax is worth discussing, so the head, neck and lungs are staged in one session. The same anaesthetic is a chance for a careful oral examination.

What the radiologist looks at

• Bone. Osteolysis, cortical destruction and periosteal reaction, which were common in maxillary SCC.
• Extension. Into the orbit, the most common extension of maxillary masses, and into neighbouring structures.
• Soft-tissue margins. Read with caution in tongue and sublingual tumours, where CT can underestimate the tumour volume.
• Lymph nodes. Size and appearance of the regional nodes, knowing that metastases can look equivocal on CT.
• The lungs. When the thorax is included, for possible metastasis.

What your report will include

Every Veheri case is read by a radiologist or neurologist, and when you order you can choose Diplomate-only reporting or the full specialist panel. You can chat directly with the specialist assigned to your case, and a simplified pet owner report helps you explain the findings to the owner.

When you take the report forward:

• Sample the mass. 19 of 60 cats treated by maxillectomy (31.7%) had benign tumours, so histology is still needed.
• Sample the nodes. Cytology of the regional nodes is usually still worth planning, whatever their size on CT, because nodal metastasis was present in 31%.
• Soft-tissue extent may be larger than on CT. For tongue and sublingual tumours in particular, the CT margin may not show the full extent of disease. This matters for surgical margins and radiotherapy fields.
• Talking to the owner: the histopathological margin was the only factor associated with survival after glosso-mandibulectomy, and CT features did not predict survival time.

What to include when you request an oral CT report

• signalment: age, breed and sex
• location of the mass on oral examination, including the soft palate
• duration, dysphagia, ptyalism, facial swelling or exophthalmos
• biopsy or cytology results, if available
• mandibular lymph node findings on palpation or cytology
• the planned treatment, so the report focuses on surgical margins, orbital and nasal extension or radiotherapy volumes

How Veheri can help

Veheri’s radiologists report veterinary CT studies remotely for clinics, and can support your team with CT scanning protocols for head and neck staging. For related reading, see CT of the canine oral cavity and oncology imaging for staging and planning.