J. S. van der Linde-Sipman

Salinomycin-induced Polyneuropathy in Cats: Morphologic and Epidemiologic Data

In April 1996, an outbreak of toxic polyneuropathy in cats occurred in the Netherlands. All cats had been fed one of two brands of dry cat food from one manufacturer. Chemical analyses of these foods, stomach contents, and liver and kidney of affected cats revealed contamination with the ionophor salinomycin. Epidemiologic and clinical data were collected from 823 cats, or about 1% of the cats at risk. In 21 affected cats, postmortem examination was performed. The affected cats had acute onset of lameness and paralysis of the hindlimbs followed by the forelimbs. Clinical and pathologic examination indicated a distal polyneuropathy involving both the sensory and motor nerves.

Feline Nasal and Paranasal Sinus Tumours: Clinicopathological Study, Histomorphological Description and Diagnostic Immunohistochemistry of 123 Cases

Histological examination was performed in 123 cats with primary nasal and paranasal sinus tumours; 117 had undergone surgical biopsy and six necropsy. Special stains and immunohistochemistry were performed on poorly differentiated cases. Ninety-two percent (113/123) of the tumours were malignant. There was an increased risk for old cats (mean age of 10.9 years), and a male predilection (59% males). Clinical signs and breeds varied with the histological type of tumour. Thirty-nine percent (48/123) of the cases presented with nasal discharge, 21% (26/123) with dyspnea, 20% (24/123) with facial swelling, and 15% (19/123) with epistaxis. Forty-three percent (53/123) of the tumours were of epithelial origin. Adenocarcinomas (18/53) and squamous cell carcinomas (17/53) were the most common epithelial tumours. Fifty percent (26/53) of the epithelial tumours originated from the pseudo-stratified respiratory epithelium of the nasal cavity, 28% (15/53) from the stratified squamous epithelium of the vestibule, 9% (5/53) from olfactory epithelium, 9% (5/53) from submucosal glands and 4% (2/53) from minor salivary glands. Malignant lymphoma (35/123) was the most common tumour. Seventy-one percent (25/35) of the malignant lymphomas were B-cell tumours and 29% (10/35) were T-cell tumours. Six cases of malignant lymphomas were proved to be epitheliotropic T-cell lymphomas. This is the first report of a primary nasal epitheliotropic T-cell lymphoma in cats.

Polycystic kidney and liver disease in cats

This paper reviews 27 cases of polycystic disease of the kidneys and/or liver in cats. The multiple cysts in the kidneys were rounded in all but one case, as described in adult polycystic kidney disease in humans. In 68% of the cats presented with polycystic kidneys, there were also cystic changes of the liver (uni- or multilocular cysts and/or congenital hepatic fibrosis (CHF)). In 1 cat polycystic changes of kidneys and liver were accompanied by cysts in the pancreas. In 5 cases there was severe pancreas fibrosis. Twenty-one of the 27 cats were Persian or Persian-crossbred.

Cutaneous Malignant Melanomas in 57 Cats: Identification of (Amelanotic) Signet-ring and Balloon Cell Types and Verification of Their Origin by Immunohistochemistry, Electron Microscopy, and In Situ Hybridization

Cutancous malignant melanomas in cats, both melanotic and amelanotic, were diagnosed in 57 of 1,530 skin tumors during the period 1991-1995. All melanomas occurred in domestic shorthaircats of ages 3-19 years (

Generalized AA-amyloidosis in Siamese and Oriental cats

X = 11.5 years). Postmortem examination was performed on 16 cats. All had metastases in the regional lymph node and several organ systems. The average time of survival after surgical removal of the tumor was 4.5 months. Histologically, five types of melanomas could be distinguished: epithelioid, spindle, mixed, signet-ring, and balloon cell. Whereas all epithelioid, spindle, and mixed epithelioid/spindle cell types showed pigmentation, signet-ring and balloon cell types were often amelanotic. Immunohistochemical examination of the melanomas revealed a positive staining for S-100, vimentin, and neuron-specific enolase. The melanomas were negative for muscle cell markers, except in some of the signet-ring cell melanomas; 13 of 21 tumors showed a weak positive staining for polyclonal desmin. Electron microscopic examination of signet-ring cell melanomas revealed an abundance of intermediate filaments, whereas in some of these tumors a few cells with melanosomes were found. Nonisotopic in situ hybridization for mRNA encoding for tyrosinase verified the melanocytic origin of the amelanotic signet-ring and balloon cell melanomas.

Familial amyloidosis in cats: Siamese and Abyssinian AA proteins differ in primary sequence and pattern of deposition

During a 7 year period (1987-1994), 194 Siamese cats including a colour variant designated Oriental cat, were presented for post-mortem examination. Twelve of these animals (6.2%) were diagnosed with amyloidosis. Major gross pathological findings included enlarged pale livers with haemorrhages, pale and swollen spleens, and dilated intestines. Deposits of amyloid were found in these tissues. The amyloid was found to cross-react with anti dog AA-antiserum when examined with peroxidase antiperoxidase (PAP) staining (four cases). Amyloid fibrils were purified by the water extraction method and its major constituting protein (AA) was isolated by gel filtration. Amino acid sequence analysis of this protein from a Siamese cat and an Abyssinian cat revealed a significant difference between these breeds. In the Siamese protein AA two amino acid substitutions (46 R for Q and 52 V for A) were encountered. This finding indicates the existence of a new feline amyloid A protein occurring in the Siamese breed which differs from presently known (apoS)AA-proteins. Additionally, the pedigree analysis of affected cats suggests a familial trait.

PRIMARY HYPERPARATHYROIDISM IN TWO CATS

Familial AA amyloidosis is a hereditary trait in Abyssinian cats, with the kidney as the main target organ. The amino acid sequence of the amyloid A protein of the Abyssinian cat has been described earlier. Recently, familial amyloidosis has been found in Siamese cats, with the liver as the main target organ. In the present paper, we describe the complete amino amid sequence of the major constituent protein, of two Siamese cats. Siamese hepatic protein AA showed homology with, but was different from all feline SAA and AA sequences hitherto reported. Two substitutions (46Q-R and 52A-V) from the Abyssinian protein sequence were identified, one of which (46Q-R) is a non-homologous substitution not found in mammalian SAA, but is present in two bird AA amyloid proteins. This shows the presence of an unique amyloidogenic SAA isotype in Siamese cats. Both the Siamese and the Abyssinian sequence are amyloidogenic, thus making identification of amyloidogenic residues difficult. Apart from the apparent inherent amyloidogenicity of SAA, it can not be excluded that certain amino acid substitutions could enhance its amyloidogenicity but also could contribute to tissue predilection in amyloidosis.

Primary and metastatic carcinomas in the digits of cats

Primary hyperparathyroidism (PHP) is an infrequently diagnosed disorder in cats. In this report the signs and symptoms of two cats with hypercalcaemia due to PHP are described, together with diagnostic approach, results of treatment, and immunohistochemical findings. A 9-year-old and a 13-year-old neutered male domestic shorthair cat were presented with signs of lethargy, anorexia, and vomiting. Both cats had persistent hypercalcaemia and normo- to hypophosphataemia. Cytological examination of a fine-needle aspiration biopsy sample of a palpable cervical mass revealed groups of benign glandular-epithelial cells in one cat. In the other cat no cervical mass was palpable. In this cat plasma parathyroid hormone (PTH) levels were measured repeatedly and these values exceeded the maximum reference value on two occasions. Following exclusion of other causes of hypercalcaemia both cats were subjected to neck surgery and in both a solitary parathyroid adenoma was removed. The adenomas contained an abundance of PTH, as demonstrated by immunohistochemical techniques. Plasma calcium and phosphate concentrations returned to within, reference ranges postoperatively. Recovery was uncomplicated and there were no signs of recurrence on follow-up examinations.

Hyperadrenocorticism in four cats

Summary In the period 1993–1998, digital carcinomas in 64 cats were examined. In all animals primary complaints were painful digit(s). Eight cats had a primary squamous cell carcinoma which involved one digit or two adjacent digits of one leg. Fifty‐six cats had metastases of a pulmonary carcinoma in the digits, and in general multiple digits of different legs were involved. In many of these cats metastases also occurred in other organs, including the skin and muscles. No primary sweat gland carcinomas of the digits were seen. Primary squamous cell carcinomas of the digits were characterized by cornification and the absence of PAS‐positive cells, PAS‐positive secretory material. Immunohistochemically, these neoplasms stained negative with the monoclonal antibody CAM 5.2 directed against Keratin 8 (K 8). The metastases of pulmonary carcinomas to the digits showed one or more of the following histological features: goblet cells, ciliated epithelial cells, PAS‐positive cells or lakes, and/or a PAS‐positive lining of luminal membranes and no cornification. Immunohistochemically, they showed positive staining for CAM 5.2 (K8). Thoracic radiographs from three cats with a primary squamous cell carcinoma showed no abnormalities, whereas all cases of metastases from a pulmonary carcinoma to the digits available for follow‐up showed evidence of a primary pulmonary carcinoma on radiography and/or postmortem examination (25 out of 56). The conclusion of this study was that most carcinomas in the digits of cats were metastases of a primary pulmonary carcinoma (87.5%). Primary squamous cell carcinomas occurred infrequently. The prognosis of metastases of a pulmonary carcinoma in the digits is poor with an averagae, survival time of 4.9 weeks, in contrast to 29.5 weeks in cats with a squamous cell carcinoma. These data stress the importance of taking thoracic radiographs of cats with digital tumours before surgical intervention.In the period 1993-1998, digital carcinomas in 64 cats were examined. In all animals primary complaints were painful digit(s). Eight cats had a primary squamous cell carcinoma which involved one digit or two adjacent digits of one leg. Fifty-six cats had metastases of a pulmonary carcinoma in the digits, and in general multiple digits of different legs were involved. In many of these cats metastases also occurred in other organs, including the skin and muscles. No primary sweat gland carcinomas of the digits were seen. Primary squamous cell carcinomas of the digits were characterized by cornification and the absence of PAS-positive cells, PAS-positive secretory material. Immunohistochemically, these neoplasms stained negative with the monoclonal antibody CAM 5.2 directed against Keratin 8 (K 8). The metastases of pulmonary carcinomas to the digits showed one or more of the following histological features: goblet cells, ciliated epithelial cells, PAS-positive cells or lakes, and/or a PAS-positive lining of luminal membranes and no cornification. Immunohistochemically, they showed positive staining for CAM 5.2 (K8). Thoracic radiographs from three cats with a primary squamous cell carcinoma showed no abnormalities, whereas all cases of metastases from a pulmonary carcinoma to the digits available for follow-up showed evidence of a primary pulmonary carcinoma on radiography and/or postmortem examination (25 out of 56). The conclusion of this study was that most carcinomas in the digits of cats were metastases of a primary pulmonary carcinoma (87.5%). Primary squamous cell carcinomas occurred infrequently. The prognosis of metastases of a pulmonary carcinoma in the digits is poor with an average survival time of 4.9 weeks, in contrast to 29.5 weeks in cats with a squamous cell carcinoma. These data stress the importance of taking thoracic radiographs of cats with digital tumours before surgical intervention.

Lymphangiosarcomas in Cats: A Retrospective Study of 12 Cases

This paper describes four cats with hyperadrenocorticism. Cat 1 showed polydipsia and polyphagia. Diabetes mellitus was initially diagnosed. As the animal appeared to be insulin resistant, pituitary and adrenocortical function tests were performed and the diagnosis of hyperadrenocorticism was made. Resistance to the high-dose dexamethasone suppression test was noticed in this cat. Pathological examination revealed a pituitary chromophobe adenoma. Cat 2 presented with diabetes mellitus, which was treated with insulin. The animal had a pendulous abdomen and its coat was in a poor condition. The low-dose dexamethasone suppression test demonstrated hyperadrenocorticism. Necropsy findings of pituitary tumour and hyperplasia of the adrenal cortex confirmed the diagnosis. Cat 3 showed clinical abnormalities indicative of hyperadrenocorticism, for instance, muscle weakness, alopecia, multiple abscesses. The diagnosis of hyperadrenocorticism was confirmed by the results of the lowe-dose dexamethasone suppression test. Pathological examination revealed an adrenocortical carcinoma. Cat 4 presented with polydipsia. The cause of this symptom was not found initially. One and a half years later additional symptoms, such as nephritis and polyphagia developed. Hyperadrenocorticism was diagnosed because of a palpable mass cranial to the left kidney. The diagnosis was confirmed by the results of the lowe-dose dexamethasone suppression test and the necropsy findings.