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A 12-year-old German shepherd crossbreed dog was presented with a submandibular mass that was initially diagnosed as myxosarcoma on incisional biopsy. Chest radiographs were taken for staging, and magnetic resonance imaging was performed to assess the feasibility of cytoreductive surgery before adjuvant radiotherapy. The dog underwent debulking surgery, and histology permitted reclassification of the tumour as a malignant mesenchymoma (with myxosarcomatous and osteosarcomatous differentiation). The dog was subsequently treated with four fractions of radiotherapy given at seven-day intervals and three doses of carboplatin. The dog remained stable following therapy until its condition acutely deteriorated, and it was euthanased 153 days after surgery. On postmortem examination, there were no signs of local tumour recurrence, but metastases were observed both in the thorax and in the abdomen.

Canine tonsillar squamous cell carcinoma is an aggressive disease with a poor prognosis. A retrospective study was undertaken of all dogs that were presented between January 1999 and January 2004 to the Animal Health Trust for the treatment of tonsillar squamous cell carcinoma. Five cases were identified, and their median survival time was 211 days (95 per cent confidence interval 80 to 352) with two of the five dogs remaining alive at the end of the study, 826 and 1628 days from diagnosis with no clinical signs of disease. The protocol was well tolerated with only one of the five dogs showing toxicity associated with carboplatin and all dogs that started radiotherapy completing it. Compared with results of previous studies, these cases suggest that surgical cytoreduction followed by coarse fractionated radiotherapy together with carboplatin may be a useful way to treat this tumour. Carboplatin alone caused partial remission in the two cases where it was used as neo-adjunctive therapy.

The pattern and relative rates of diametric growth of the avian eye and cornea are described throughout embryonic development. The effect of reduced intraocular pressure on eye and corneal diametric growth also was investigated. Between embryonic day 4 (E4) and 1 day posthatching, the eye undergoes two distinct phases of linear growth. The first phase (E4-10) is very rapid (1.193 mm/day). The second phase, after E10, is significantly slower (0.346 mm/day). By contrast, over the same developmental period, the cornea undergoes three distinct and sequential phases of linear growth. The second phase of corneal growth (E7-10) is the most rapid (0.429 mm/day) and separates two periods of slow growth (0.211 mm/day during E4-7 and 0.128 mm/day after E10). After the sustained release of intraocular pressure by intubation on E4, growth of both the eye and cornea is reduced significantly. Operated eyes grow at a rate of 0.356 mm/day (E4-10) and 0.155 mm/day (E10-16). Intubation reduces corneal growth to a single phase of 0.125 mm/day (E7-16). Thus, from E4-10 both the eye and cornea possess intrinsic growth potentials that are elevated significantly by intraocular pressure. After E10, the rate of growth of both the eye and the cornea is independent of intraocular pressure. Because both control and intubated eyes change their growth rate on E10, this transition also is independent of intraocular pressure. This contrasts with the cornea which, after intubation, shows no detectable variation in growth rate. Correlation of eye with corneal growth demonstrates an exponential relationship in the presence of intraocular pressure and an almost linear relationship after intubation.