Endolymphatic Sac Tumor in Two Dogs.

Endolymphatic sac tumors (ELSTs) are rare neoplasms of the inner and middle ear described in humans. Diagnosis of such neoplasms is difficult and largely dependent on a combination of histologic, immunohistochemical, and clinical findings. Although the neoplastic cells lack cellular features of malignancy, these are clinically aggressive tumors that often invade the surrounding temporal bone. Here, we describe 2 dogs with middle ear masses that share morphologic, immunohistochemical, and clinical similarities with human ELSTs. Advanced imaging of the masses revealed evidence of aggressive behavior such as bony lysis of the temporal bone. Histologically, the neoplastic epithelial cells formed papillary structures, lacked mitotic figures, and had mild anisocytosis and anisokaryosis. The neoplastic cells were immunohistochemically positive for cytokeratin AE1/AE3 but were negative for chromogranin, synaptophysin, and thyroglobulin. Local invasion and bone destruction but no evidence of metastases suggest a clinical behavior similar to human ELSTs.

Expression of fibroblast growth factor 23 by canine soft tissue sarcomas.

Tumour-induced osteomalacia (TIO) is a rare paraneoplastic syndrome of humans. Some mesenchymal tumours (often resembling haemangiopericytomas) express molecules that normally regulate phosphorus metabolism; most frequently, fibroblast growth factor 23. Patients develop renal phosphate wasting and inappropriately low serum concentrations of 1, 25 (OH)2 vitamin D3 , leading to osteomalacia. Surgical removal of the tumour is curative. The authors examined expression of canine fibroblast growth factor 23 in 49 soft tissue sarcomas, and control tissues from normal adult dogs. RNA extracted from bone or formalin-fixed, paraffin-embedded tissues was analysed by end point and quantitative reverse transcriptase-polymerase chain reaction. Fibroblast growth factor 23 expression was detected in bone, lung, kidney, lymph node and thymus. Fifteen of 49 sarcomas (31%) expressed fibroblast growth factor 23, three of these had high relative expression and some features resembling phosphatonin-expressing mesenchymal tumours of humans. Further work is required to determine whether TIO may occur in dogs.

Fibroblast Growth Factor 23: A New Dimension to Diseases of Calcium-Phosphorus Metabolism.

Traditionally, control of phosphorus in the body has been considered secondary to the tighter control of calcium by parathyroid hormone and vitamin D. However, over the past decade, substantial advances have been made in understanding the control of phosphorus by the so-called phosphatonin system, the lynchpin of which is fibroblast growth factor 23 (FGF23). FGF23 binds to the klotho/FGFR1c receptor complex in renal tubular epithelial cells, leading to upregulation of Na/Pi cotransporters and subsequent excretion of phosphorus from the body. In addition, FGF23 inhibits parathyroid hormone and the renal 1α-hydroxylase enzyme, while it stimulates 24-hydroxylase, leading to decreased 1,25-dihydroxyvitamin D3. FGF23 is intimately involved in the pathogenesis of a number of diseases, particularly the hereditary hypophosphatemic rickets group and chronic kidney disease, and is a target for the development of new treatments in human medicine. Little work has been done on FGF23 or the other phosphatonins in veterinary medicine, but increases in FGF23 are seen with chronic kidney disease in cats, and increased FGF23 expression has been found in soft tissue sarcomas in dogs.

Identification of the first New Zealand case of equine multinodular pulmonary fibrosis.

CASE HISTORY: A 10-year-old polo mare presented with a history of weight loss, poor condition and inappetance. CLINICAL FINDINGS: The mare was tachycardic, tachypnoeic and febrile. Harsh lung sounds were auscultated over all lung fields. The mare initially responded to treatment with antibiotics, anti-inflammatory drugs and bronchodilators. Throughout the course of treatment, there was a variable lymphocytosis, monocytosis and fluctuation in concentrations of fibrinogen. The mare also developed a mild anaemia, most likely due to chronic disease. Despite treatment, the mare's condition deteriorated over the following 2 months, and she was subject to euthanasia. PATHOLOGICAL FINDINGS: On post mortem examination, white to pale tan, large coalescing fibrous nodules up to 5 cm in diameter were found distributed throughout the lungs. Histopathology revealed a multifocally severe interstitial pneumonia with superimposed bronchiolar or alveolar inflammation, fibrosis, Type II pneumocyte hyperplasia and histiocytic intranuclear inclusion bodies, consistent with the findings previously reported for cases of equine multinodular pulmonary fibrosis (EMPF). DIAGNOSIS: Equine multinodular pulmonary fibrosis based on characteristic gross and histopathological findings. The diagnosis was strengthened by detection of DNA for equine herpesvirus 5 in the lung tissue. CLINICAL RELEVANCE: This report describes the first recognised case of EMPF in New Zealand. The affected horse did not respond to treatment and was subject to euthanasia. The prognosis for horses with EMPF, based on a limited number of cases worldwide, is currently considered poor.

Transcoelomic spread and metastasis of a squamous cell carcinoma of presumed pancreatic duct origin in a cat.

CASE HISTORY: A 13-year-old female spayed domestic shorthaired cat was examined because of lethargy, inappetance and weight loss. CLINICAL FINDINGS: No clinically significant haematological or biochemical abnormalities were detected, but an abdominal mass was palpated. Abdominal examination using ultrasonography revealed soft tissue masses in the cranial abdomen, involving the spleen, as well as the liver and abdominal wall; the pancreas was not identified. Despite supportive therapy the condition of the cat rapidly deteriorated and euthanasia was performed. PATHOLOGICAL FINDINGS: Cytological preparations from the cranial abdominal mass revealed a population of pleomorphic epithelial cells consistent with a squamous cell carcinoma. On post-mortem examination, firm creamy white to yellow nodular masses were present in the region of the pancreatic left limb, spleen, liver, diaphragm, right abdominal wall and in the left lung. Sections of all masses were examined histopathologically and demonstrated infiltration by neoplastic epithelial cells indicative of squamous cell carcinoma (SCC). DIAGNOSIS: Squamous cell carcinoma of presumed pancreatic duct origin. CLINICAL RELEVANCE: There are few reports of haematogenous or lymphatic metastasis of SCC in cats, and none reporting transcoelomic spread. This report describes the clinical and pathological features of a case of presumed primary pancreatic ductal SCC, and should alert veterinarians to the potential for metastasis and carcinomatosis.