Rib metastases from a non-tonsillar squamous cell carcinoma in a dog

Metastatic spread to the ribs in a 15-year-old, male, neutered, Irish setter is reported occurring secondary to an oral squamous cell carcinoma (SCC). The dog presented with a history of a rapidly growing SCC of the right upper incisive region, which was confirmed by histopathology as a SCC. Thoracic radiographs showed bony lesions associated with the body of the right third rib, and the fifth and seventh costal cartilages. A rostral partial maxillectomy was performed as palliative treatment for the oral mass and a core biopsy of the lesion on the third rib was performed. The rib lesion was identified histopathologically as a metastatic SCC. A review of the literature of oropharyngeal SCC and the metastatic potential of non-tonsillar SCC is presented, in particular metastatic bone disease. This case report suggests possible implications of metastatic bone disease for treatment and prognosis for future cases of non-tonsillar SCC.     

Multiple skeletal metastases from a penile squamous cell carcinoma in a horse

A 21‐year‐old gelding with ventral abdominal and preputial oedema was evaluated for right hindlimb lameness. Partial phallectomy had been performed 3 years prior for treatment of squamous cell carcinoma. Regional analgesia did not localise the source of lameness and nuclear scintigraphy was recommended. The results of the scan revealed severe increased radiopharmaceutical uptake in the proximal femur. Radiographic and ultrasound examinations were inconclusive. The horse was discharged with recommendations of stall confinement and a 2 week course of nonsteroidal anti‐inflammatory drugs. Four weeks later the horse presented for an inability to elevate his neck and persistent hindlimb lameness. The owner elected humane euthanasia. Post mortem examination revealed metastatic squamous cell carcinoma in the proximal femur and fifth cervical vertebrae consistent with metastasis from the penile squamous cell carcinoma. To the authors’ knowledge, multiple site bone metastasis of squamous cell carcinoma has not been reported previously in the horse.     

Skeletal metastasis from a squamous cell carcinoma of the nictitating membrane in a Haflinger horse

A 12-year-old Haflinger gelding with a history of a persistent cough was referred for evaluation of a severe lameness of the left forelimb. An excision of the right nictitans had been performed 2 years prior to presentation, and a squamous cell carcinoma (SCC) with embolic neoplastic cells in several blood vessels had been confirmed by histopathology. The origin of the lameness could not be localised with regional analgesia; therefore, a nuclear scintigraphic examination was performed. This revealed an area of marked increased radiopharmaceutical uptake at the level of the caudodorsal border of the left scapula. Further examination, including ultrasound-guided biopsy of the suspect region, confirmed the presence of SCC invading the scapula. Due to poor a prognosis, the horse was subjected to euthanasia. Prior to euthanasia, the gelding was tested homozygous for the missense variant in the damage-specific DNA-binding protein 2 (DDB2) gene, which is reported as a risk factor for the development of nictitans SCC in Haflinger horses. Post-mortem evaluation revealed multiple SCC metastasis, affecting the scapula, the liver and the lungs. To the authors' knowledge, this is the first reported case of bone metastasis following a primary periocular SCC in a horse.     

Resection cystoplasty of a squamous cell carcinoma in a mare

A 22‐year‐old Arabian mare was examined for evaluation of haematuria of 2 months' duration. Complete blood cell count and chemistry revealed anaemia of chronic disease (i.e. normocytic, normochromic) and hypoproteinaemia. Cystoscopy revealed a haemorrhagic mass protruding into the lumen of the urinary bladder in the apical region. The mass was surgically removed by partial cystectomy performed through a caudal ventral midline laparotomy. Histological examination of the mass confirmed the diagnosis of squamous cell carcinoma. Tumours of the equine urinary bladder are rare, and when a partial cystectomy is indicated, a caudal ventral midline laparotomy may provide adequate surgical exposure even in adult horses.     

Pigmented squamous cell carcinoma of the conjunctiva of a horse

Abstract A heavily pigmented tumor was removed from the lateral, perilimbal, bulbar conjunctiva of a bay Thoroughbred horse. Excision was incomplete and the base of the tumor was lasered on the assumption that the tumor was a melanoma. No other ophthalmic lesions were seen. Histology showed the mass to be a pigmented squamous cell carcinoma (SCC). The prognosis and recommended treatment protocols are different for SCC and melanoma. This is, to the best of our knowledge, the first report of an ocular, pigmented SCC in the veterinary literature.     

Pleuroscopic diagnosis of gastroesophageal squamous cell carcinoma in a horse

A 15-year-old Quarter Horse gelding was examined because of chronic intermittent colic of 40 days' duration. The clinical signs included acute onset of depression, ptyalism, abdominal splinting, and rolling within an hour of eating. An intramural mass of the esophagus was identified during esophagoscopy. A large soft-tissue density surrounding the distal portion of the esophagus, creating a stricture, was identified on an esophagogram. With the horse slightly sedated, pleuroscopy was performed, allowing direct visualization and biopsy of the mass. The histopathologic diagnosis was squamous cell carcinoma.     

Pseudohyperparathyroidism in a mare associated with squamous cell carcinoma of the vulva

An 18-year-old Appaloosa mare was examined because of squamous cell carcinoma of the vulva, anorexia with pronounced weight loss, and hypercalcemia. The tumor had developed rapidly over a period of 3 months and externally extended ventrally involving the perineum and the dorsal aspect of the udder. Necropsy examination demonstrated a large primary squamous cell carcinoma of the vulva, perineum, and mammary gland with metastases to the supramammary, sublumbar, deep inguinal, and mediastinal lymph nodes. No gross renal lesions were observed and, histologically, there was only mild vacuolation of renal tubular epithelium. Based on the normal concentration of serum parathyroid hormone, the absence of evidence of hypervitaminosis D, and normal renal function, a diagnosis was made of hypercalcemia of malignancy or pseudohyperparathyroidism. The mechanism responsible for hypercalcemia was not determined, but the histologic type of the neoplasm and the clinical course suggested possible production of a humoral hypercalcemic factor by the neoplasm, similar to that demonstrated in certain types of human squamous cell carcinoma.     

Hemangiosarcoma and squamous cell carcinoma in the third eyelid of a horse

A 12-year-old Belgian draft horse presented for a right eye third eyelid mass and red-tinged ocular discharge of 3 months' duration. The third eyelid was excised and submitted for histopathology. On histopathologic examination, the mass was composed of both hemangiosarcoma and squamous cell carcinoma. The horse developed thickened eyelids and hemorrhagic ocular discharge from the right eye approximately 16 months following surgery, and was euthanized. Necropsy and histopathology confirmed local recurrence and regional metastasis of the hemangiosarcoma. This was an unusual case because there were two distinct neoplastic processes composing the same mass that could not be differentiated grossly.     

Treatment of oral squamous cell carcinoma in a horse by surgical debulking followed by metronomic chemotherapy

A 19‐year‐old Quarter Horse gelding presented with a 6‐week history of hypersalivation, halitosis and dysmasesis. Oral examination revealed retention of food and saliva and the presence of a raised, nodular, 6 × 7 cm, ulcerated mass on the dorsal surface of the tongue base. The mass was confirmed histologically as squamous cell carcinoma. Complete resection of the mass was not possible and surgical laser debulking was followed 15 days later by chemotherapy with a combination of meloxicam and cyclophosphamide in metronomic regimen. After one week, there was a significant improvement in clinical signs and food consumption returned to normal. Therapy was well tolerated with no alteration in haematological or urinalysis parameters. After 5 months of excellent life quality, the horse showed progressive difficulties in mastication and swallowing. Endoscopic examination showed extension of the tumour to all the aboral aspect of the tongue and, with the owner's consent, the patient was subjected to euthanasia. This is believed to be the first report on the combined use of meloxicam and cyclophosphamide in a metronomic fashion for management of an oral squamous cell carcinoma in a horse. Since metronomic therapy is less expensive than conventional chemotherapy, easily administrable and well tolerated, it should be considered as a possible treatment option for nonresectable equine malignant tumours.     

A Shetland pony with a squamous cell carcinoma of the stomach

A 12-year-old Shetland pony was referred because of weight loss over several months and symptoms of colic. On rectal examination, enlarged mesenteric lymph nodes and an abnormal mass in the left anterior abdominal cavity were palpated. Haematological evaluation revealed leucocytosis (13 G.l-1) and an abnormal electrophoretic pattern (31.8% albumin, 18.8% alpha-globulins, 29.0% beta-globulins, 20.4% gamma-globulins). Peritoneal fluid collected by abdominal paracentesis did not contain neoplastic cells. Gastroscopy was performed and a mass, with areas of ulceration and necrosis, was visualized within the oesophageal region of the stomach. The diagnosis 'squamous cell carcinoma' of the stomach was confirmed histologically at necropsy.     

Multiple squamous cell carcinoma of the digits in two cats

This paper describes the clinical and pathological features of two cats with squamous cell carcinoma affecting several digits. Similar lesions have been described in dogs and humans.     

Challenges in the treatment of equine periocular squamous cell carcinoma

Management of periocular squamous cell carcinoma is challenging because of the need for adjunctive therapy, the adverse effects of therapies and the frequent recurrence of SCC. Appropriate treatment of equine ocular SCC usually involves surgical excision combined with adjunctive therapy selected as appropriate for the anatomic site of the lesion. Metastasis of periocular SCC has been reported to occur in approximately 6–15% of cases. The horse owner should be carefully educated to understand that for best long‐term results from the treatment of periocular SCC, they must be diligent in observing signs of recurrence or metastasis and be willing to have the horse examined as soon as adverse signs are observed. Furthermore, external beam radiation may be effective in the treatment of metastatic SCC and further clinical studies of this treatment modality are needed.     

Immunotherapy of periocular squamous cell carcinoma with metastasis in a pony.

A 5-year-old Pony of America mare was referred for evaluation of inflamed upper and lower right eyelids. Squamous cell carcinoma of the eyelids and ulcerative keratitis secondary to self-trauma were diagnosed. Initial treatment of the eyelid neoplasia with 2 applications of cryotherapy failed to resolve the lesions, and immunotherapy with bacillus of Calmette-Guerin (BCG) was instituted. Multiple injections of BCG over a 17-week period resulted in progressive shrinkage of the tumor mass, but regional metastasis to the ipsilateral submandibular lymph node occurred. Six months later, ocular neoplastic lesions were not evident, and the lymph node had regressed in size. Eighteen months after the diagnosis of metastatic disease, signs of recurrence were not noticed in either the primary or secondary tumor sites. Squamous cell carcinoma of the equine eyelid historically carries a poor prognosis for resolution. Immunotherapy for equine ocular squamous cell carcinoma should be considered as a treatment alternative to cryosurgery, radiotherapy, hyperthermy, and CO2 laser ablation, especially in cases involving the eyelid.     

Electrochemotherapy for the treatment of squamous cell carcinoma in cats: a preliminary report

Squamous cell carcinomas (SCC) of the skin are commonly described in cats. Reported treatments include surgery, radiation therapy and photodynamic therapy. This preliminary study reports on the management of these lesions combining the local administration of bleomycin (plus hyaluronidase for a more uniform distribution) with permeabilizing biphasic electric pulses. Nine cats with SCC graded T(2)-T(4) were treated over a 5 year period, and each cat received two sessions of electrochemotherapy (ECT) 1 week apart. The side effects of this treatment were minimal and limited to mild erythema of the nose. Seven of the cats (77.7%) had a complete response lasting up to 3 years. ECT seems to be a safe and effective option for the treatment of feline sun-induced squamous cell carcinomas and warrants further investigation.     

Long-term outcome of treatment of a squamous cell carcinoma of the foot by amputation of the distal limb in a pony

This report describes a rare case of squamous cell carcinoma (SCC) in a 10-year-old Shetland pony. The pony was presented for evaluation of a chronic, ulcerating mass of the foot associated with a nonweightbearing lameness of the right forelimb. Foot radiographs revealed an aggressive bone lesion with severe osteolysis of the distal phalanx. Amputation of the digit was performed under general anaesthesia at the level of the metacarpophalangeal joint using a palmar flap technique and a transfixation cast for protection of the stump. Avascular necrosis, infection and dehiscence of the stump occurred 3 weeks later and a second amputation was performed at the level of the proximal third of the third metacarpal bone. Histopathology revealed a squamous cell carcinoma. After healing of the stump, a prosthesis was fitted to the limb for improved ambulation of the pony. Two years after the amputation, telephone follow-up with the referring veterinarian and the owner, revealed that the pony was healthy and able to go out daily in a paddock with its prosthesis. SCC represents an unusual indication for limb amputation. Successful outcome is rarely reported in horses.