Prognostic value of increased intraepithelial lymphocytes and lymphocytic clonality in dogs with chronic enteropathy or small-cell lymphoma.

The clinical significance of severe infiltration of small intraepithelial lymphocytes (IEL) and the results of polymerase chain reaction for antigen receptor rearrangement (PARR) in dogs with chronic enteropathy (CE) and small-cell lymphoma (SCL) are controversial. This cohort study aimed to evaluate the prognostic significance of the IEL and PARR results in dogs with CE or SCL. Although definitive diagnostic histopathological criteria for SCL in dogs have yet to be established, dogs with the histopathological findings of severe IEL infiltration were diagnosed with SCL in this study. One hundred and nineteen dogs were recruited, with 23 dogs classified as having SCL and 96 dogs as having CE. The positive rate of PARR was 59.6 % (71/119) in the duodenum and 57.7 % (64/111) in the ileum. Subsequently, three dogs with SCL and four dogs with CE developed large-cell lymphoma (LCL). The median overall survival (OS) of dogs with SCL was 700 days (range, 6-1410 days), and that of dogs with CE was not reached. In the log-rank test, shorter OS was observed in cases with histopathological SCL (P = 0.035), clonal TCRγ rearrangement in the duodenum (P = 0.012), and clonal IgH rearrangement in the ileum (P < 0.0001). The Cox proportional hazards model adjusted for sex and age showed that histopathological SCL (hazard ratio [HR] 1.74; 95 % confidence interval [CI], 0.83-3.65), duodenal clonal TCRγ rearrangement (HR, 1.80; 95 % CI, 0.86-3.75), and ileal clonal IgH rearrangement (HR, 2.28; 95 % CI, 0.92-5.70) could shorten overall survival, although their 95 % CIs included 1.0. These results indicate that severe IEL infiltration could be a useful histopathological feature for diagnosing SCL, and clonality-positive results could be a negative prognostic factor in dogs with CE. Furthermore, the development of LCL should be carefully monitored in dogs with CE and SCL..

Spontaneous intranasal tumours in degus (Octodon degus): 20 cases (2007-2020).

OBJECTIVE: The objective of this retrospective study was to describe the clinical and histopathological findings associated with intranasal tumours in degus. MATERIALS AND METHODS: Medical records of degus diagnosed with intranasal neoplasms on histopathological examination between the years 2007 and 2020 at one hospital were included in the study. RESULTS MEDICAL RECORDS OF DEGUS: Twenty degus (10 males and 10 females) were eligible for inclusion. Initial clinical signs included sneezing, abnormal nasal sounds, and nasal discharge, followed by anorexia and frequent nose rubbing. On radiography, 15 out of 20 animals showed space-occupying lesions in the nasal cavity. CT was performed in 16 animals and revealed various degrees of changes, including abnormal radiopacity within the nasal cavity and damaged nasal septum. Rhinostomy and excisional biopsy was performed in all 20 animals. Six out of 20 patients died during the perioperative period. Six and seven degus survived for 3 months and 1 year, respectively. One animal was lost to follow-up. In 16 cases the histological diagnosis was consistent with fibromas, while in 4 cases with osteomas. CLINICAL SIGNIFICANCE: Intranasal neoplasms in degus are mostly benign mesenchymal tumours with various degrees of bone formation, which is unique to this animal species. This occurrence should be considered as an important differential diagnosis for upper respiratory tract disease in degus.

Spontaneous oral tumours in 18 rabbits (2005-2015).

This retrospective study of a series of 18 cases aimed to describe the clinical and pathological findings of oral tumours in rabbits, as there have been few reports detailing spontaneous oral tumours in this species. A total of 13 different tumour types were diagnosed: squamous cell carcinoma (three), ameloblastoma (two), fibrosarcoma (two), osteosarcoma (two), cementoma (one), complex odontoma (one), giant cell epulis (one), sarcoma (one), chondrosarcoma (one), trichoepithelioma (one), papilloma (one), malignant melanoma (one) and basal cell carcinoma (one). Odontogenic tumours were relatively common in this study as compared to the oral tumours typically identified in dogs and cats. The most common clinical sign in this study was feeding abnormalities. Surgical excision and radiation therapy were found to be effective in rabbits.

Spontaneous intranasal tumours in rabbits: 7 cases (2007-2019).

OBJECTIVES: Neoplasms that arise in the nasal cavity are reported infrequently in rabbits. This case series aims to review and determine the clinical behaviour of neoplasms in the nasal cavity in rabbits. MATERIALS AND METHODS: A retrospective study was conducted on seven pet rabbits diagnosed with intranasal tumours to describe the clinical and histopathological findings and prognoses after surgery and/or radiotherapy. RESULTS: The most common clinical signs were nasal snoring when breathing, nasal discharge, and subsequent dyspnoea and anorexia. Six different histopathological types of tumours were diagnosed: intranasal adenocarcinoma, squamous cell carcinoma, osteosarcoma, carcinoid tumour, osteoma, and lymphoma. Skull radiography only revealed the abnormalities in three of seven cases but on CT, the intranasal masses were more clearly identified in all cases. All cases received tumour resection through rhinostomy and four cases received radiotherapy after surgery. In the six cases with a known outcome, the survival time after surgery was more than 13 months. CLINICAL SIGNIFICANCE: This case series provides an insight of the behavior of intranasal neoplasms in rabbits. Surgical treatment and radiotherapy could improve their clinical sings.

Evaluation of epithelial and mesenchymal cell markers in canine urinary bladder transitional cell carcinoma.

Canine transitional cell carcinoma (cTCC) is the most common malignant tumour in the urinary bladder: it is highly invasive and exhibits metastatic characteristics. Inflammation is also strongly related to cTCC. Epithelial tumours often exhibit a mesenchymal cell phenotype during tumour invasion and metastasis owing to epithelial-mesenchymal transition (EMT), which is often induced in chronic inflammation. The aim of this retrospective study was to investigate the expression of epithelial and mesenchymal cell markers in tumour cells and to evaluate its relationship with prognosis of cTCC. In this study, 29 dogs with cTCC who underwent surgical treatment were enrolled. Clinical parameters were reviewed using medical records. Tissue expression of epithelial and mesenchymal markers was evaluated by immunohistochemical analysis. The association between the expression of mesenchymal cell markers and clinical parameters, including prognosis, was statistically examined. In five normal bladder tissues used as controls, no expression of mesenchymal markers was observed, except for one tissue that expressed fibronectin. Conversely, epithelial tumour cells expressed vimentin and fibronectin in 23/29 and 19/28 cTCC tissues, respectively. Regarding clinical parameters, vimentin score in Miniature Dachshunds was significantly higher than those in other dog breeds (P < 0.001). Multivariate survival analyses revealed that age>12 years was related to shorter progression-free survival (P = 0.02). Higher vimentin score, lower fibronectin score, and advanced clinical T stage were significantly correlated with shorter median survival time (P < 0.05). The results of this study indicate that vimentin expression was associated with cTCC progression. Further studies are needed to examine the incidence and relevance of EMT in cTCC.

Histological and Immunohistochemical Features of Normal Histiocytes and Langerhans Cells, and Histiocytic Sarcomas in Four-Toed Hedgehogs (Atelerix albiventris).

Histiocytic sarcoma (HS) is a haematopoietic tumour of histiocyte origin that has been sporadically reported in four-toed hedgehogs (Atelerix albiventris). The present study aimed to investigate clinical, gross, histopathological and immunohistochemical features of HS in eight hedgehogs. Histological and immunohistochemical features of normal histiocytes and Langerhans cells (LCs) of hedgehogs were also investigated. HLA-DR-, Iba-1- and E-cadherin-positive LCs were observed in the epidermis, while Iba-1- and CD204-positive histiocytes were detected in the lymph nodes and spleen of normal hedgehogs. Localized HS (six cases) developed in the skin and spleen, while disseminated HS (two cases) occurred in the intestine. Tumour cells of disseminated HS were also distributed within the mesenteric lymph nodes, liver, kidney, spleen, lung and adrenal glands. Tumour cells of both localized and disseminated HS were composed of histiocytic cells, spindle to pleomorphic cells, multinucleated giant cells and erythrophagocytic cells. Most tumour cells were immunopositive for Iba-1, CD204 and lysozyme. A small number of tumour cells were positive for E-cadherin and CD208, and the tumour cells in one case were positive for HLA-DR. These results suggest that the tumour cells have variable features of histiocyte origin, including dendritic cells, LCs and macrophages. The behaviour of HS in the hedgehog was very aggressive, and 50% of cases died within 90 days of resection. The present study also highlighted the tendency for local tumour recurrence in localized cutaneous HS cases, suggesting a requirement for a long-term follow-up after excision.

Duodenal expression of antimicrobial peptides in dogs with idiopathic inflammatory bowel disease and intestinal lymphoma.

Although antimicrobial peptides (AMPs) play an integral role in the regulation of intestinal microbiota and homeostasis, their expression in canine gastrointestinal diseases, including idiopathic inflammatory bowel disease (IBD) and intestinal lymphoma, remains unknown. The objective of this study was to investigate the intestinal expression of AMPs in dogs with IBD or intestinal lymphoma. IBD was diagnosed in 44 dogs, small cell intestinal lymphoma in 25 dogs, and large cell intestinal lymphoma in 19 dogs. Twenty healthy beagles were used as normal controls. Duodenal mRNA expression of six representative AMPs - lactoferrin, lysozyme, cathelicidin, secretory leukocyte peptidase inhibitor (SLPI), bactericidal/permeability increasing protein (BPI), and canine beta defensin (CBD103) - was quantified by real-time reverse transcription polymerase chain reaction. The relative expression of BPI, lactoferrin, and SLPI was significantly higher in dogs with IBD and intestinal lymphomas than in healthy controls. Interestingly, the expression patterns of AMPs differed between dogs with IBD and those with intestinal lymphomas, especially small cell lymphoma. Increased expression of BPI differentiated IBD from dogs with small cell intestinal lymphoma, with a sensitivity of 93.2%, a specificity of 100%, and an area under the curve of 0.955. These results suggest that the expression patterns of AMP aid in the diagnosis of canine IBD and intestinal lymphoma, although it remains uncertain whether the altered AMP expression is the cause or effect of mucosal inflammation.

An Outbreak of Fatal Bordetella bronchiseptica Bronchopneumonia in Puppies.

Twenty-two newborn puppies that did not receive colostrum exhibited acute respiratory signs and died at a breeding facility. Pathological examinations were performed on four of the puppies. At necropsy examination, the lungs were firm and mottled dark red, consistent with acute bronchopneumonia. Histopathologically, there was marked infiltration of neutrophils and macrophages into the bronchi and alveoli, and gram-negative coccobacilli were attached diffusely to the cilia of bronchial mucosa. Immunohistochemistry for Bordetella bronchiseptica antigen revealed positive labelling of the bacterial agents. On electron microscopy, a large number of coccobacilli were observed attaching to the cilia of bronchial epithelial cells. Real-time polymerase chain reaction amplified a B. bronchiseptica gene from the affected lung tissue. Based on these findings, the four puppies were diagnosed with fatal B. bronchiseptica bronchopneumonia.

Expression of Stem Cell Factor in Feline Mast Cell Tumour.

Stem cell factor (SCF) is a ligand of the molecule Kit, which is expressed in mast cells and is important for mast cell proliferation, migration and survival. Mast cell tumours (MCTs) are associated with mutations of c-kit, a proto-oncogene encoding the Kit protein. In this study, we examined SCF expression in 23 samples of feline MCTs. SCF expression was detected in 10 cutaneous MCTs and a case of splenic mastocytosis. In the cutaneous MCTs, SCF-positive tumour cells were located at the margins. Kit was expressed in eight of the 10 cutaneous cases of SCF-expressing MCTs. In these cases, Kit-positive cells were located near to SCF-positive cells, and SCF/Kit double-positive tumour cells were found. Ki67-positive tumour cells were not found near to SCF-positive cells. These results suggest that SCF autocrine/paracrine mechanisms are involved in the expansion of cutaneous MCTs, but not in tumour proliferation.

Clinical and clinicopathological characteristics of acute lymphoblastic leukaemia in six cats.

OBJECTIVES: To investigate the clinical characteristics of feline acute lymphoblastic leukaemia patients diagnosed according to the recent diagnostic criteria for the equivalent canine condition. MATERIALS AND METHODS: The medical records of six cats diagnosed with acute lymphoblastic leukaemia were retrospectively reviewed to extract data on clinicopathological characteristics and outcomes. The lymphoid origin of the tumour cells was confirmed by polymerase chain reaction for antigen receptor gene rearrangement, flow cytometry or immunohistochemistry. RESULTS: Non-specific clinical signs such as lethargy and anorexia were common, and anaemia and thrombocytopenia were also commonly identified. Leucocytosis was observed in four cats and leucopenia was observed in two; the number of lymphoblasts in the peripheral blood samples varied among the cases. Lymphoblasts originated from B-cell lineage in four cats and T-cell lineage in one, and those of another cat were positive for both B-cell marker CD21 and T-cell marker CD8. Five of the six cats were treated with cytotoxic chemotherapy, and a partial response was obtained in two. The median overall survival was 55 days (range: 1 to 115). CLINICAL SIGNIFICANCE: Acute lymphoblastic leukaemia should be considered if lymphoblasts are observed in peripheral blood, even if their number is small. The prognosis for cats that have acute lymphoblastic leukaemia is as poor as that for dogs, and further studies are needed to develop effective treatment.

Clinical features and outcomes of Merkel cell carcinoma in 20 cats.

The biological behaviour and prognostic factors of Merkel cell carcinoma (MCC) in 20 cats were studied. The tumours were surgically removed and histopathologically examined. The animals were 8 to 20 years old (median age: 14 years), and the tumours were predominantly located in the neck and head. Follow-up data were available in 17 cases, and 12 cats died within a year of surgery. The overall median survival time after resection was 243 days (range 16-360 days). Recurrence occurred in 11 cases, although 6 of them (55%) were found to be margin-negative. Possible metastasis occurred after the surgery in 10 cases, although 6 of them (60%) were found to be margin-negative. The histopathological features of MCC included tumour necrosis in 16 cases (80%), vascular invasion in 6 cases (38%) and high mitotic counts (median: 28.5 per high-power field). Irregular acanthosis was noted adjacent to the tumours in 9 cases (60%). Immunohistochemically, the tumour cells were positive for cytokeratin (CK) 20 and p63 in all cases, synaptophysin in 19 (95%) cases, and CK18 in 16 cases (80%). The study shows that feline MCC is associated with a poor prognosis and exhibited a strong tendency towards local recurrence, regional lymph node metastasis and distant spread.

Pathological features of intestinal T-cell lymphoma in Shiba dogs in Japan.

Intestinal T-cell lymphoma is being more frequently diagnosed in dogs owing to the wide availability of endoscopy and clonality analysis in veterinary medicine. However, no epidemiological study on intestinal T-cell lymphoma has been previously performed, and hence, information about dog breed, age and sex distributions of intestinal T-cell lymphoma has largely remained unclear. In this study, breed predisposition to canine intestinal T-cell lymphoma was determined by calculating odds ratios and 95% confidential intervals. Of the 43 breeds identified, 7 appeared to have an increased risk of developing intestinal T-cell lymphoma, including Shiba dogs, German shepherds, Cairn terriers, Boston terriers, Papillons, Pugs and Maltese. Immunohistochemistry of representative Shiba cases revealed ubiquitous cytotoxic immunophenotype in both large and small cell lymphomas. Interestingly, CD20 co-expression was observed in 11% of cases. It could potentially be aberrant expression of CD20 or neoplastic transformation of a normal subset of CD20-positive T-cells. A comparison of mean age between representative breeds revealed that Shiba dogs were slightly younger than Miniature Dachshunds (P < .05). However, there was no difference in survival between the 2 breeds. As Shiba dogs are predisposed to chronic enteropathy, there may be underlying inflammatory process contributing to lymphomagenesis of intestinal T-cell lymphoma in this breed. Our findings provide insights into the underlying pathogenesis of breed-specific canine intestinal T-cell lymphoma.

Amyloid-producing Odontoameloblastoma in a Black-tailed Prairie Dog (Cynomys ludovicianus).

A 6-year-old female black-tailed prairie dog (Cynomys ludovicianus) was presented with a space-occupying lesion in the left submandibular region. On computed tomography, a low attenuating, poorly circumscribed mass infiltrated the left mandibular bone, with osteolytic change. Microscopically, the lesion was composed of odontogenic epithelium proliferating in nests and embedded in abundant dental papilla-like ectomesenchyme, including dentine and enamel. Multifocal amyloid deposition was observed. Immunohistochemically, the neoplastic epithelial cells were positive for cytokeratin (CK) AE1/AE3, CK14 and p63. Some epithelial cells were positive for amelogenin and some adjacent to the amyloid deposits co-expressed S100. The ectomesenchymal cells expressed vimentin and strong S100 immunoreactivity was observed in odontoblast-like cells. The amyloid was immunolabelled with amelogenin. The tumour was diagnosed as amyloid-producing odontoameloblastoma.

Association of tumour-infiltrating regulatory T cells with adverse outcomes in dogs with malignant tumours.

Regulatory T cells (Tregs) infiltrate into a variety of tumour tissues and associate with poor prognosis in humans. However, data on association of Treg infiltration with prognosis is limited in canine tumours. The purpose of this study was to examine the number of tumour-infiltrating Tregs and its association with overall survival (OS) in dogs with malignant tumours. The following 168 canine tumours were included: 37 oral malignant melanomas (OMMs); 14 oral squamous cell carcinomas (OSCCs); 16 pulmonary adenocarcinomas (PAs); 37 mammary carcinomas (MCs); 36 mast cell tumours (MCTs) and 28 hepatocellular carcinomas (HCCs). Normal tissues were obtained from 8 healthy dogs as controls. The number of forkhead box P3 (Foxp3)-positive Tregs in intratumoral and peritumoral areas was investigated by immunohistochemistry. OS was compared between high and low Treg groups. The number of intratumoral and peritumoral Foxp3-positive Tregs was significantly higher in OMM, OSCC, PA and MC compared with each normal tissue. There were few Foxp3-positive Tregs in MCT and HCC. With intratumoral Tregs, the OS in the high Treg group was significantly shorter than that in the low Treg group in OMM, OSCC and PA. With peritumoral Tregs, there was no significant difference for OS between the 2 groups in each tumour type. These results suggest that Tregs infiltrate into a variety of canine tumours and the abundance of Tregs are associated with poor prognosis in some solid tumour types.

IgA Antibodies Against Gliadin and Tissue Transglutaminase in Dogs With Chronic Enteritis and Intestinal T-Cell Lymphoma.

Molecular clonality analysis of T-cell receptor (TCR) genes for diagnosing T-cell lymphoma is widely used in veterinary medicine. However, differentiating chronic enteritis (CE) from intestinal lymphoma is challenging because of the incompatibility between histopathologic and clonality analysis results. On the basis of findings that canine intestinal T-cell lymphoma and celiac disease share some common features, we conducted serologic examinations in combination with histopathologic and T-cell receptor clonality analyses in 48 dogs diagnosed with either CE or intestinal lymphoma. Immunoglobulin A (IgA) and immunoglobulin G (IgG) antibodies against gliadin and tissue transglutaminase (tTG) were quantitatively measured using ELISA. The conditions were classified according to the histopathologic diagnosis, clonality analysis, and combined histopathologic/clonality analysis. Histopathologic analysis showed that dogs with intestinal lymphoma were likely to have high levels of serum IgA antibodies against gliadin and tTG, and serum IgG antibodies against tTG. No correlation between the diagnosed groups and control group was observed in the results of the clonality analysis and histopathologic/clonality analysis. It is interesting that dogs with intestinal lymphoma had a higher serum IgA titer against gliadin and tTG than did dogs with CE. These results suggest an association between repetitive inflammatory stimulation by gliadin peptides and subsequent intestinal lymphoma in dogs.

Histopathological and Immunohistochemical Study of Trichoblastoma in the Rabbit.

Trichoblastoma is the most common skin tumour in the rabbit. The aim of the present study was to characterize the histological and immunohistochemical features of trichoblastoma in 27 rabbits. Common sites of tumour occurrence were the neck (6/30, 20%), head (5/30, 16.7%), flank (4/30, 13.3%) and hindlimb (4/30, 13.3%). Histologically, rabbit trichoblastoma was categorized into ribbon (10/30, 33.3%), trabecular (8/30, 26.7%) and mixed types (12/30, 40%). The tumour tissue showed close interaction with the surrounding stroma where prominent fibroblastic aggregation, known as papillary mesenchymal bodies, was frequently observed (24/30; 80%). Peritumoural stroma of all cases was stained by Alcian blue (at pH 2.5 with weaker staining at pH 1.0). Immunohistochemically, the peripheral palisading basal-type cells of the tumour were positive for cytokeratin (CK) 14 while the inner cells were typically positive for CK17, differing from the immunohistochemical profile of the rabbit epidermis and hair follicle. The present study suggests that uncontrolled embryonic trichogenesis is involved in the development of trichoblastoma in the rabbit.

Endoscopic Cytology for the Diagnosis of Chronic Enteritis and Intestinal Lymphoma in Dogs.

Although cytology is a rapid diagnostic procedure in dogs, the cytologic criteria of endoscopic biopsies for chronic enteritis and intestinal lymphoma are not well defined. An immediate diagnosis using cytology would benefit patients by enabling prompt initiation of therapy. The objective of this study was to investigate the correlation between the results of endoscopic cytology and histopathology. In this study, 167 dogs with clinical signs of chronic gastrointestinal disease were included. On the basis of histopathology, the following diagnoses were determined: lymphocytic-plasmacytic enteritis in 93 dogs; eosinophilic enteritis in 5 dogs; small cell intestinal lymphoma in 45 dogs; and large cell intestinal lymphoma in 24 dogs. Two clinical pathologists retrospectively evaluated the endoscopic cytology of squash-smear preparations. The cytologic diagnoses of inflammation, small cell lymphoma, and large cell lymphoma were based on the severity of lymphocyte infiltration, the size of infiltrated lymphocytes, and eosinophil/mast cell infiltration. The clinical severity score was significantly increased along with the degree of lymphocyte infiltration evaluated by cytology. The cytologic diagnosis was in complete agreement with the histopathologic diagnosis in 136 of 167 (81.4%) cases. For the differentiation between enteritis and lymphoma, endoscopic cytology had a sensitivity of 98.6%, a specificity of 73.5%, a positive predictive value of 72.3%, and a negative predictive value of 98.6%. The log-rank test and Cox regression analysis showed that the results of cytology predicted the prognosis. These results suggest that endoscopic cytology is a useful technique to aid diagnosis of intestinal inflammation and lymphoma in dogs.

Variations in Histiocytic Differentiation of Cell Lines From Canine Cerebral and Articular Histiocytic Sarcomas.

Two newly established canine histiocytic sarcoma (HS) cell lines, designated as PWC-HS01 and FCR-HS02, were obtained from brain and articular tumors, respectively. These 2 HS cell lines had phagocytic ability and modal chromosome aberrations. Although morphologic features of both HS cells were similar, immunocytochemical examinations revealed that the PWC-HS01 cell line expressed both dendritic cell (ie, S100, CD208, CD1, and CD4) and macrophage (ie, CD68, CD163, and CD204) markers. In contrast, the FCR-HS02 cell line was immunonegative for CD204 and CD68 but consistently positive for the dendritic cell markers. Moreover, reverse transcription polymerase chain reaction analyses confirmed histiocytic differentiation of both HS cell lines. These results suggest that HS from the central nervous system may have a tendency to be more undifferentiated compared with cases from other organs. In addition, the 2 newly established HS cell lines were also tumorigenic and metastatic in immunodeficient mice, supporting that these cell lines can be used as new tumor models for investigating canine histiocytic diseases.

Deposition, Clearance, and Reinduction of Amyloid A Amyloid in Interleukin 1 Receptor Antagonist Knockout Mice.

Amyloid A (AA) amyloidosis is characterized by the extracellular deposition of AA amyloid and results in the irreversible dysfunction of parenchymal organs. In experimental models, AA amyloid deposits are cleared following a decrease in circulating serum amyloid A (SAA) concentrations. Additional inflammatory stimuli during this recovery process may induce more severe amyloid redeposition. In the present study, we confirmed the deposition, clearance, and reinduction of AA amyloid deposits in interleukin 1 receptor antagonist knockout mice (IL-1raKO) and studied the SAA levels and amyloid-enhancing factor activity based on the time-dependent changes of amyloid deposition. Histopathologically, following initial (day 0) injection of amyloid-enhancing factor in combination with an inflammatory stimulus (silver nitrate [AgNO3]), amyloid deposition peaked by day 20, and its deposition gradually decreased after day 35. SAA concentrations in serum were precipitously elevated on day 1 but returned to normal levels by day 10, whereas the SAA dimer was detected in serum after day 45. An additional AgNO3 injection was administered to mice with amyloidosis on day 5, 10, 35, or 50, and all mice developed large amyloid deposits. Amyloid deposition was most severe in mice treated with AgNO3 on day 35. The inoculation of sera from mice with AA amyloidosis, combined with AgNO3, induced AA amyloidosis. Serum samples collected on days 35 and 50, which contained high concentrations of the SAA dimer, induced amyloidosis in a high proportion (83%) of mice. Therefore, increased SAA and/or its dimer in serum during the recovery process may markedly exacerbate the development of AA amyloidosis.

Lachrymal Gland Basal Cell Adenocarcinoma in a Ferret (Mustela putorius furo).

A 1 cm diameter mass was detected in the caudal superotemporal area of the left eye of a 6-year-old neutered male ferret (Mustela putorius furo). The mass and the left eye were removed surgically. Microscopical examination revealed a tumour of the adnexal gland of the eye that had invaded the surrounding ocular muscle. The tumour was composed of basal-type epithelial cells arranged in a solid, or occasionally tubular, pattern. Immunohistochemically, the tumour cells expressed cytokeratin and p63, but not smooth muscle actin. Based on these findings, the tumour was diagnosed as a basal cell adenocarcinoma of the lachrymal gland. In addition to the tumour, the retina of the left eye was detached and folded at the centre of the globe. This is the first report of a non-human case of basal cell adenocarcinoma of the lachrymal gland.