Description of clinical and pathological findings, treatment and outcome of feline large granular lymphocyte lymphoma (1996-2004)

Feline high-grade and large granular lymphocyte alimentary lymphomas treated with COP- or CHOP-based chemotherapy: A multi-centric retrospective study of 57 cases

Specific data regarding outcome of cats with high-grade and large granular lymphocyte alimentary lymphoma (HGAL and LGL, respectively) treated with multi-agent chemotherapy are scarce. The aims of this multi-centric, retrospective study were to describe the outcome of cats with HGAL and LGL treated with COP- or CHOP-based chemotherapy and to identify potential prognostic factors. Cats with a cytological or histological diagnosis of HGAL or LGL lymphoma treated with COP- or CHOP-based protocol as first-line chemotherapy were included. Data regarding diagnosis, staging, treatment and follow-up were collected. Fifty-seven cats treated with CHOP (n = 37) or COP (n = 20) protocols were included. Complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) were observed in 20%, 22%, 36% and 22% of cats, respectively, for an overall response rate of 42%. Median progression-free interval (PFI) was 148 days and overall median survival time (OST) was 131 days. Cats achieving CR, PR or SD showed significantly longer PFI (p < .01) and OST (p < .015) compared with cats with PD. Other positive prognostic factors in multi-variate analysis were rescue treatment (p < .001) and absence of lymph node involvement (p < .03). Negative prognostic factors were diffuse infiltration of the gastrointestinal tract (p = .035) and infiltration of a non-haematopoietic organ (p < .01).

In vitro chemosensitivity testing of the feline large granular lymphocyte cell line (S87)

BACKGROUND

Feline large granular lymphocyte (LGL) lymphoma is an aggressive neoplasia characterised by short survival and poor response to chemotherapy.

OBJECTIVES

In this study, the effect of different chemotherapeutic agents on the growth kinetics of the feline cell line S87, a non-MHC-restricted feline LGL cell line, was investigated. Where possible, IC50 (inhibitory concentration 50) values were determined. The IC50 values of the cell line as lymphoma models can provide clues to the situation in vivo and serve as a basis for studying resistance mechanisms.

METHODS

Cells were incubated with various concentrations of vincristine, doxorubicin, 4-hydroperoxycyclophosphamide, prednisolone, methotrexate and L-asparaginase for 24 and 48 h, respectively.

RESULTS

The IC50 values could be determined as 14.57 (7.49-28.32) μg/mL at 24 h incubation and 5.72 (4.05-8.07) μg/mL at 48 h incubation for doxorubicin and 9.12 (7.72-10.76) μg/mL at 24 h incubation and 4.53 (3.74-5.47) μg/mL at 48 h incubation for 4-hydroperpoxycyclophosphamide. Treatment with vincristine and methotrexate resulted in relatively high cell resistance whereas L-asparaginase and prednisolone treatment led to a reduction in cell number compared to control while cell viability was not affected (cytostatic effect).

CONCLUSION

Overall, the feline LGL cell line S87 proves to be relatively sensitive to doxorubicin and 4-hydroperoxycyclophosphamide and relatively resistant to treatment with vincristine, prednisolone, methotrexate and L-asparaginase. The results of this study can be used for further investigations on resistance mechanisms in feline LGL lymphoma. Doxorubicin and cyclophosphamide can be interpreted as promising candidates for the therapy of feline LGL lymphomas.

ACVIM consensus statement guidelines on diagnosing and distinguishing low-grade neoplastic from inflammatory lymphocytic chronic enteropathies in cats

BACKGROUND

Lymphoplasmacytic enteritis (LPE) and low-grade intestinal T cell lymphoma (LGITL) are common diseases in older cats, but their diagnosis and differentiation remain challenging.

OBJECTIVES

To summarize the current literature on etiopathogenesis and diagnosis of LPE and LGITL in cats and provide guidance on the differentiation between LPE and LGITL in cats. To provide statements established using evidence-based approaches or where such evidence is lacking, statements based on consensus of experts in the field.

ANIMALS

None.

METHODS

A panel of 6 experts in the field (2 internists, 1 radiologist, 1 anatomic pathologist, 1 clonality expert, 1 oncologist) with the support of a human medical immunologist, was formed to assess and summarize evidence in the peer-reviewed literature and complement it with consensus recommendations.

RESULTS

Despite increasing interest on the topic for clinicians and pathologists, few prospective studies were available, and interpretation of the pertinent literature often was challenging because of the heterogeneity of the cases. Most recommendations by the panel were supported by a moderate or low level of evidence. Several understudied areas were identified, including cellular markers using immunohistochemistry, genomics, and transcriptomic studies.

CONCLUSIONS AND CLINICAL IMPORTANCE

To date, no single diagnostic criterion or known biomarker reliably differentiates inflammatory lesions from neoplastic lymphoproliferations in the intestinal tract of cats and a diagnosis currently is established by integrating all available clinical and diagnostic data. Histopathology remains the mainstay to better differentiate LPE from LGITL in cats with chronic enteropathy.

Serum amyloid A and other clinicopathological variables in cats with intermediate- and large-cell lymphoma

OBJECTIVES

Serum amyloid A (SAA) concentrations are increased in cats with lymphoma vs healthy cats; however, the association between SAA concentrations and prognosis in cats with lymphoma is unclear. The aim of this study was to evaluate if SAA concentrations were different in cats with nasal vs non-nasal lymphoma, if SAA concentrations are prognostic in patients treated with high-dose chemotherapy and if SAA concentrations are correlated with other clinicopathological variables.

METHODS

Cats diagnosed with intermediate- or large-cell lymphoma between 2012 and 2022 with SAA concentration data available were included. Associations between tumour site (nasal vs non-nasal), stage, response to treatment and SAA concentration were evaluated using non-parametric statistics. Associations between SAA concentrations and stage with survival time were evaluated using Cox regression analysis. Patients with nasal tumours and those not receiving high-dose chemotherapy were excluded from the survival analyses.

RESULTS

Thirty-nine cats were included. Median SAA concentrations were significantly higher in non-nasal compared with nasal lymphoma (42 µg/ml [range <0.3-797] vs <0.3 µg/ml [range <0.3-0.9]; P = 0.026). SAA concentrations did not correlate with tumour stage. Median survival time for patients with non-nasal tumour and undergoing chemotherapy was 49 days (range 2-1726). Responders had a better median survival time than non-responders (273 days [range 43-1728] vs 39 days [range 2-169]; P <0.001), whereas SAA concentrations were not associated with survival time. Lower haematocrit at presentation was associated with a reduced median survival time (P = 0.007).

CONCLUSIONS AND RELEVANCE

In the population examined, no correlation between serum concentration of SAA and prognosis in patients with lymphoma was identified, while low haematocrit and lack of response to treatment were both found to be associated with survival time. SAA concentrations were elevated in patients with non-nasal lymphoma vs patients with tumours confined to the nasal cavity.

Pathohistological features of mediastinal lymphoma in domestic cats

The article covers two clinical cases of domestic cats suffering from a mediastinal form of lymphoma and provides their cytological, immunohistochemical, and pathohistological verification. The lymphoma immunophenotyping method using the B-cell markers CD79a and CD3 was used to identify T-cells. The mediastinal type of lymphoma in cats is usually rarely registered and statistically, the number of cases does not exceed 20%, which is consistent with our observations. Shortness of breath, difficulty with swallowing, lack of appetite, cyanotic mucous membranes, lymphadenomegaly of the mediastinal lymph nodes and effusion in the chest cavity were found in the clinically ill cats. An X-ray examination of the chest cavity revealed an increased contrast in the mediastinal area and displacement of the lungs towards the spine. A complete blood count revealed lymphopenia. Cytological smears of the chest cavity transudates revealed mostly monomorphic lymphoblasts with large rounded hyperchromic nuclei and narrow cytoplasm stained in light blue. The karyoplasm was somewhat granular, the nucleoli were visible, and the mitoses were atypical and numerous. The cytological picture in biopsy samples of mediastinal lymph nodes was characterized by a monomorphic population of lymphoblasts with an eccentrically located nucleus and moderately basophilic karyoplasm. The cell cytoplasm was vacuolated in some places, with presence of atypical mitotic figures. Most of the cells had two nuclei. Diffuse tumoral lesions of the chest cavity tissues, focal tumorous lesions of the lung parenchyma, and lymphadenopathy of the mediastinal lymph nodes were found during the autopsy in the first case. The second clinical case demonstrated the massive lymphadenopathy of the mediastinal lymph nodes. Histologically, a diffuse lesion by a monomorphic population of lymphoblasts was revealed in preparations from the soft tissues of the chest wall. The lymphoblasts’ insignificant cytoplasm, with nuclei from round to elliptical shape, infiltrated the chest wall’s soft tissues. It was found immunohistochemically that the blast cells showed reactivity to CD79a, and were mostly negative to CD3. This indicates the development of a large diffuse B-cell lymphoma. The immunohistochemical picture of lymph node necropsies from another cat was somewhat similar. However, it was also characterized by lymphoblasts with eccentrically placed nuclei, increased number of cells with mitotic figures, somewhat intensive CD3 antibodies expression (especially in the paracortical area of lymph nodes), and significant CD79a marker expression.

Primary multifocal muscular T-cell lymphoma with cutaneous involvement in a dog: A case report and review of the literature

Canine lymphoma represents a heterogeneous group of lymphoid neoplasms, with multicentric nodal lymphoma being the most common presentation. Musculoskeletal involvement is uncommon, and primary muscular lymphoma is a very rare presentation. Only a few cases have been described in dogs, which were of variable classification and immunophenotype. Here, we report the case of a 5-year-old female neutered Beagle that presented with an intramuscular mass on the right shoulder and associated lameness and lethargy. One month after initial presentation, multiple cutaneous nodules appeared on the head, and staging with advanced imaging revealed additional masses affecting other muscles. Cytology, histopathology, immunohistochemistry, and PCR for antigen receptor rearrangements of one of the muscle masses and skin lesions supported a diagnosis of peripheral T-cell lymphoma with large granular lymphocytes at both sites. The dog was euthanized after diagnosis due to the poor prognosis. This is the first report of primary muscular peripheral T-cell lymphoma with large granular lymphocytes and cutaneous involvement in the dog. Despite being a rare presentation, lymphoma must be considered a differential in dogs presenting with a discrete, intramuscular, soft tissue mass.

[Chronic enteropathies in cats - diagnostic and therapeutic approach]

Chronic enteropathies are characterized by persistent or recurrent gastrointestinal signs including vomiting, diarrhoea, weight loss, anorexia and lethargy for a minimum duration of 3 weeks. Diagnosis is by excluding other disease processes and includes faecal examinations, blood screenings (e. g., thyroidal, pancreatic, liver dysfunctions, investigation for infectious diseases, vitamin B₁₂ status), diagnostic imaging, histopathological evaluation using biopsies from several different gastrointestinal segments and the response to therapeutic trials. Chronic inflammatory enteropathies are classified as food-responsive enteropathy (FRE), antibiotic-responsive enteropathy (ARE), immunosuppressant-responsive or, similarly -refractory enteropathy (IRE). Small-cell (low-grade) alimentary lymphoma (LGAL), a crucial differential diagnosis, is predominantly seen in older cats. The feline chronic enteropathy activity index (FCEAI), a clinical scoring system, was established to objectively assess the severity of clinical illness and to evaluate the response to treatment. In general, the prognosis depends on the underlying aetiology. Cats diagnosed with FRE typically have a good long-term prognosis with adequate dietary management. The response to treatment varies in cats with IRE, with same cats experiencing frequent relapses of clinical signs and still others being non-responsive to treatment. Prognosis for LGAL, with adequate treatment, is usually fair to good (median survival time 510-704 days).

A case of feline large granular lymphocyte lymphoma with complete remission and long survival by surgical resection and adjuvant nimustine administration

A 7‐year‐old spayed female Scottish Fold cat presented with a 4‐week history of anorexia, weight loss and vomiting. Abdominal ultrasonography revealed a jejunal mass and a slightly enlarged jejunal lymph node. A fine‐needle aspiration of the mass revealed many round cells with multiple small intracytoplasmic magenta granules. The mass was diagnosed as a large granular lymphocyte (LGL) lymphoma based on cytology. The LGL lymphoma was completely resected via open surgery. The histologic and cytologic evaluations showed no neoplastic findings in the jejunal lymph node, liver, spleen, kidney or bone marrow. The LGL lymphoma was localized to the jejunum. Postoperatively, the cat received chemotherapy with nimustine, l‐asparaginase and prednisolone. The cat is currently receiving nimustine every 6 weeks, without adverse events, and treatment has been administrated a total of 18 times up until day 552. The cat is in a good condition, and the LGL lymphoma has not recurred. Nimustine should be considered one of the effective chemotherapeutic agents in the treatment of feline LGL lymphoma cases in the future.

Cyclophosphamide rescue therapy for relapsed low-grade alimentary lymphoma after chlorambucil treatment in cats

OBJECTIVES

The aims of this study were to evaluate the response, outcome and prognostic factors in cats with clinically presumed relapsed low-grade alimentary lymphoma (LGAL) receiving cyclophosphamide as a first-line rescue therapy after failing chlorambucil treatment.

METHODS

The medical records of 20 cats (from three institutions, between 2002 and 2017) treated with cyclophosphamide for relapsed LGAL after initial treatment with chlorambucil were retrospectively reviewed. Progression-free survival (PFS), overall survival time (OST) and the association of select variables with measures of outcome were assessed. Adverse events (AEs) were also described.

RESULTS

Eighteen cats (90%) achieved a complete clinical response (CR) for a median duration of 239 days. The median PFS was 215 days. The median OST was 1065 days. The only clinical factor associated with a longer PFS was achievement of a CR with cyclophosphamide treatment. Cyclophosphamide was associated with few and reversible constitutional, gastrointestinal and hematologic AEs.

CONCLUSIONS AND RELEVANCE

Cyclophosphamide appears to be a safe and effective first-rescue therapeutic option for cats with relapsed LGAL.

Incidence and treatment of feline renal lymphoma: 27 cases

OBJECTIVES

Lymphoma is the most common feline hematopoietic malignancy. Incidence of renal lymphoma has not been reported as a subset of a large population of feline lymphoma cases. Previous studies have reported renal lymphoma as both a singular entity as well as a component of multicentric disease. The clinical presentation, diagnostic evaluation, therapy and outcomes related to renal lymphoma have not been reported since Mooney et al in 1987. This retrospective study aimed to describe the incidence of renal lymphoma, clinical signs, treatment and survival.

METHODS

Using a database of cats diagnosed with lymphoma between January 2008 and October 2017, cats with renal lymphoma were selected for further analysis. Cases were retrospectively staged according to Mooney et al (1987) and Gabor et al (1998). Data collected included age, clinical signs, clinicopathologic data, diagnostic imaging findings, lymphoma diagnostic method(s), treatment protocol(s) and survival time. Analyses comparing median survival based on therapy administered, renal lymphoma vs multicentric lymphoma, central nervous system involvement, presence of azotemia, anemia and International Renal Interest Society (IRIS) stage at diagnosis were performed.

RESULTS

From a population of 740 cats with lymphoma, 27 cats had renal lymphoma (incidence, 3.6%), and 14 of those cats had multicentric lymphoma. Fewer stage IV and V cases were identified in this data set compared with Mooney et al; however, not all cats were completely staged. Median survival (range) for cats receiving corticosteroids alone compared with those receiving an L-CHOP (L-asparaginase, vincristine, cyclophosphamide, doxorubicin, prednisolone)-based protocol was 50 days (20-1027 days) in the corticosteroid group and 203 days (44-2364 days) for the L-CHOP group (P = 0.753) for cats that died secondary to lymphoma.

CONCLUSIONS AND RELEVANCE

Neither clinical stage nor other factors were predictive of survival. Prospective studies are required to determine the optimal chemotherapy protocol.

Investigation of relationships between body weight and age among domestic cats stratified by breed and sex

OBJECTIVE To evaluate mean body weight (BW) over the lifespan of domestic cats stratified by breed and sex (including reproductive status [neutered vs sexually intact]). ANIMALS 19,015,888 cats. PROCEDURES Electronic medical records from veterinary clinics in the United States and Canada from 1981 to 2016 were collected through links to practice management software programs and anonymized. Age, breed, sex and reproductive status, and BW measurements and measurement dates were recorded. Data were cleaned, and descriptive statistics were determined. Linear regression models were created with data for 8-year-old domestic shorthair, medium hair, and longhair (SML) cats to explore changes in BW over 3 decades (represented by the years 1995, 2005, and 2015). RESULTS 9,886,899 of 19,015,888 (52%) cats had only 1 BW on record. Mean BW for cats of the 4 most common recognized breeds (Siamese, Persian, Himalayan, and Maine Coon Cat) peaked between 6 and 10 years of age and then declined. Mean BW of SML cats peaked at 8 years and was subjectively higher for neutered than for sexually intact cats. Mean BW of neutered 8-year-old SML cats increased between 1995 and 2005 but was steady between 2005 and 2015. CONCLUSIONS AND CLINICAL RELEVANCE The large dataset for this study yielded useful information on mean BW over the lifespan of domestic cats. This could be a basis for BW management discussions during veterinary visits. A low frequency of repeated BW measurements suggested a low frequency of repeated veterinary visits, especially after 1 year of age, making engagement of cat owners in the health of their animals particularly relevant.

Immunophenotypic characterization and clinical outcome in cats with lymphocytosis

Background

Lymphocytosis is relatively common in cats, but few studies describe lymphocyte populations or the clinical course associated with different immunophenotypic expansions.

Hypothesis/Objectives

We hypothesized that cats frequently develop non‐neoplastic lymphocytosis and that different neoplastic immunophenotypes have variable prognoses. We aimed to characterize the lymphocyte expansions in a large population of cats with lymphocytosis and to assess clinical presentation and outcome in a subset.

Animals

Three cohorts of cats older than 1 year with lymphocytosis (>6000/μL) were examined to define immunophenotypic categories (n = 146), evaluate outcome (n = 94), and determine prevalence of immunophenotypes (n = 350).

Methods

Retrospective study of cats with blood submitted for flow cytometry. Medical records (n = 94) were reviewed for clinical data, treatment, and survival information.

Results

Five major immunophenotypic categories were identified: B cell, heterogeneous (≥2 lineages expanded), CD4+ T cell, CD4−CD8− (double negative [DN]) T cell, and CD5‐low‐expressing T cell. B‐cell and heterogeneous phenotypes were more consistent with a non‐neoplastic process, having polyclonal antigen receptor gene rearrangements, younger age at presentation, lower lymphocyte counts, and prolonged survival. The neoplastic phenotypes, CD4+ T cell, DN T cell, and CD5 low T cell, had different median survival times (752 days [n = 37], 271 days [n = 7], 27.5 days [n = 12], respectively). Among CD4+ T‐cell cases, cats with abdominal lymphadenopathy, intestinal involvement, or both and females had shorter survival. Among 350 cats with lymphocytosis, CD4+ T‐cell lymphocytosis was most common, followed by heterogeneous and B‐cell phenotypes.

Conclusions and Clinical Importance

Neoplastic CD4+ T‐cell lymphocytosis is common in cats and has a prolonged clinical course compared to aberrant T‐cell phenotypes. Cats with heterogeneous and B‐cell lymphocyte expansions commonly have non‐neoplastic disease.

Outcomes in 40 cats with discrete intermediate- or large-cell gastrointestinal lymphoma masses treated with surgical mass resection (2005-2015)

OBJECTIVE

To report outcomes in cats with discrete intermediate- and large-cell gastrointestinal (GI) lymphoma masses after surgical resection.

STUDY DESIGN

Retrospective clinical case series.

ANIMALS

Forty client-owned cats in which intermediate- or large-cell GI lymphoma was diagnosed.

METHODS

Records of 40 cats in which discrete intermediate- or large-cell GI lymphoma masses were diagnosed between 2005 and 2015 were reviewed. Cats were included if they survived curative intent surgery and had a known outcome for at least two weeks. Postoperative death was permitted. Data collected included anatomic site, surgical margins, lymphoma subtype, chemotherapy use, and postoperative and long-term outcome (beyond two weeks).

RESULTS

Affected sites consisted of small intestines (n = 23), large intestines (n = 9), and stomach (n = 8). Thirty-six of 40 cats survived to discharge, and 31 cats were alive at suture removal. Median long-term follow-up of 22 cats was 111 days (range, 16-1407). Cats that survived to suture removal had a median survival time (MST) of 185 days (95% confidence interval: 72-465). Cats with large intestinal masses lived longer than those with small intestinal or gastric masses whether all cats (MST, 675, 64, 96 days, respectively; P = .03) or only those surviving to suture removal were considered. Complete surgical resection (n = 20) was positively associated with survival (370 vs 83 days, P = .016).

CONCLUSION

Most cats in this population survived the perioperative period, with MST similar to those reported historically with medical management.

CLINICAL SIGNIFICANCE

Surgical resection may be a reasonable consideration in cats with solitary lymphoma, particularly those with large intestinal masses.

Feline low-grade alimentary lymphoma: an emerging entity and a potential animal model for human disease

BACKGROUND

Low-grade alimentary lymphoma (LGAL) is characterised by the infiltration of neoplastic T-lymphocytes, typically in the small intestine. The incidence of LGAL has increased over the last ten years and it is now the most frequent digestive neoplasia in cats and comprises 60 to 75% of gastrointestinal lymphoma cases. Given that LGAL shares common clinical, paraclinical and ultrasonographic features with inflammatory bowel diseases, establishing a diagnosis is challenging. A review was designed to summarise current knowledge of the pathogenesis, diagnosis, prognosis and treatment of feline LGAL. Electronic searches of PubMed and Science Direct were carried out without date or language restrictions.

RESULTS

A total of 176 peer-reviewed documents were identified and most of which were published in the last twenty years. 130 studies were found from the veterinary literature and 46 from the human medicine literature. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. The pathophysiology of feline LGAL still needs to be elucidated, not least the putative roles of infectious agents, environmental factors as well as genetic events. The most common therapeutic strategy is combination treatment with prednisolone and chlorambucil, and prolonged remission can often be achieved. Developments in immunohistochemical analysis and clonality testing have improved the confidence of clinicians in obtaining a correct diagnosis between LGAL and IBD. The condition shares similarities with some diseases in humans, especially human indolent T-cell lymphoproliferative disorder of the gastrointestinal tract.

CONCLUSIONS

The pathophysiology of feline LGAL still needs to be elucidated and prospective studies as well as standardisation of therapeutic strategies are needed. A combination of conventional histopathology and immunohistochemistry remains the current gold-standard test, but clinicians should be cautious about reclassifying cats previously diagnosed with IBD to lymphoma on the basis of clonality testing. Importantly, feline LGAL could be considered to be a potential animal model for indolent digestive T-cell lymphoproliferative disorder, a rare condition in human medicine.

Large granular leukemia with concurrent central nervous system and articular infiltration in a cat

A 2-year-old female domestic shorthair cat was referred with a 2 month history of lethargy, weight loss, recurrent hyperthermia and polyarthropathy despite prednisolone. Upon physical examination, the cat showed apathy, hyperthermia, multiple appendicular joint pain and swelling. The CBC showed severe macrocytic normochromic non-regenerative anemia and thrombocytopenia. A population of immature large granular lymphocytes (LGL) was noted on blood smear. Abdominal ultrasonography revealed enlarged mesenteric lymph nodes (LNs), hyper echoic liver and splenomegaly. Cytology of fine needle aspirate of synovial fluid, spleen, liver, enlarged abdominal LNs and bone marrow supported a diagnosis of LGL leukemia with concurrent articular infiltration. A COP-based protocol was initiated with L-asparaginase (400 UI/kg intramuscularly) and prednisolone (1 mg/kg/day orally). However, the cat presented 1 week later with obtundation and paresis, indicating the involvement of the central nervous system (CNS). LGL were also observed on cerebrospinal fluid analysis. Histologic examination noted LGL in the spleen, liver and LNs. Immunohistochemistry (IHC) yielded negative results for both B- and T-cells thus suggesting NK-cells. The diagnosis was LGL leukemia with concurrent articular and CNS involvement. Articular infiltration with LGL is rarely reported in small animals, whereas CNS involvement was previously only suspected in a cat at necropsy.

Does categorisation of lymphoma subtypes according to the World Health Organization classification predict clinical outcome in cats?

Objectives

The purpose of this study was to specify lymphoma subtypes according to the World Health Organization (WHO) classification in a group of cats and to investigate their potential prognostic value.

Methods

Records of cats from the University of Veterinary Medicine Vienna suffering from lymphoma were reviewed in this retrospective study. To diagnose various subtypes specified in the WHO classification, histopathological and immunohistochemical examinations, as well as clonality assays in some cases, were performed.

Results

Of the 30 cats included in this study and classified according to the WHO guidelines, peripheral T-cell lymphoma was the most prevalent lymphoma subtype (37% of cases; n = 11), followed by diffuse large B-cell (23%; n = 7), intestinal T-cell (10%; n = 3), T-cell-rich B-cell (10%; n = 3), large granular lymphocytic (7%; n = 2), anaplastic large T-cell (7%; n = 2), B-cell small lymphocytic (3%; n = 1) and T-cell angiotropic lymphoma (3%; n = 1). The median survival time (MST) was 5.4 months (range 6 days to 2.2 years), with two cats still alive after 1.7 and 2.0 years, respectively. Treating cats prior to chemotherapy with glucocorticoids did not worsen their prognosis. Adding to chemotherapy, radiotherapy or surgery did not improve the clinical outcome. We observed that patients with intestinal T-cell lymphoma lived significantly longer (MST 1.7 years) than those with a diffuse large B-cell (MST 4.5 months) or peripheral T-cell lymphoma (MST 6.1 months). Cats with T-cell-rich B-cell lymphoma survived significantly longer (MST 1.2 years) than those with a diffuse large B-cell lymphoma.

Conclusions and relevance

A detailed diagnosis of feline lymphoma can be obtained by allocating different subtypes according to the WHO classification. From the eight detected lymphoma subtypes, two, intestinal T-cell lymphoma and T-cell-rich B-cell lymphoma, showed promising survival times in cats.

A retrospective evaluation of lomustine (CeeNU) in 32 treatment naïve cats with intermediate to large cell gastrointestinal lymphoma (2006-2013)

Multi-drug chemotherapy protocols for feline lymphoma have demonstrated variable efficacy and tolerability. In phase I trials, lomustine has demonstrated efficacy for cats with lymphoma though its use for treatment naïve feline intermediate/large cell gastrointestinal (GI) lymphoma remains unknown. This study evaluated the efficacy and tolerability of lomustine for the treatment of feline GI lymphoma. Thirty-two cats with histologically or cytologically confirmed intermediate/large cell GI lymphoma were evaluated retrospectively. Factors assessed included clinical signs, hematologic/biochemical parameters and use of l-asparaginase at induction. A response rate of 50% (16/32), with median duration of response of 302 days (range 64-1450 days), was found. Median progression-free interval was 132 days (range 31-1450 days), with overall median survival time of 108 days (range 4-1488 days). History of hyporexia, presence of anaemia and dose of lomustine were significantly associated with progression-free survival. Overall, lomustine is a well-tolerated and effective treatment for feline GI lymphoma.

Identification of a novel feline large granular lymphoma cell line (S87) as non-MHC-restricted cytotoxic T-cell line and assessment of its genetic instability

Feline large granular lymphocyte lymphomas are rare but very aggressive tumors with a poor prognosis. In this study, a cell line from an abdominal effusion of a cat with large granular lymphoma was characterized. Immunophenotype staining was positive for CD3 and CD45R, and negative for CD4, CD8, CD56, CD79α, BLA.36 and NK1. A TCR γ gene rearrangement was detectable by PARR. Neither FeLV antigen nor exogenous FeLV provirus could be detected. A chromosomal instability associated with a centrosome hyperamplification could also be determined. The cell line is able to lyse target cells without antigen presentation or interaction with antigen presenting cells. Therefore, these cells were classified as genetically instable non-MHC-restricted cytotoxic T cells with large granular lymphocyte morphology.

SOLITARY T-CELL HEPATIC LYMPHOMA WITH LARGE GRANULAR LYMPHOCYTE MORPHOLOGY IN A CAPTIVE CHEETAH (ACINONYX JUBATUS)

A 13-yr-old male cheetah (Acinonyx jubatus) presented for an acute history of lateral recumbency and anorexia. Upon physical examination under general anesthesia, severe icterus was noted. A serum biochemical profile confirmed markedly elevated total bilirubin and alanine transaminase. Based on ultrasound-guided liver aspirates and cytology, a presumptive diagnosis of large granular lymphocyte hepatic lymphoma was reached. Abdominal and thoracic radiographs did not assist in reaching an antemortem diagnosis. Postmortem examination and histopathology provided a definitive diagnosis of hepatic lymphoma with acute massive hepatocelluar necrosis and hemorrhage, as well as concurrent lesions of gastric ulcers, ulcerative and sclerosing enteritis, myocardial hypertrophy, and splenic myelolipomas. Immunohistochemistry of the liver yielded CD-3 positive and CD-20 negative results, confirming lymphocytes of a T-cell lineage. Due to concern for possible retrovirus-associated disease, enzyme-linked immunosorbent assays for feline leukemia virus and feline immunodeficiency virus were performed retrospectively on a banked serum sample and yielded negative results, thus diminishing concern for the male conspecific housed in the same exhibit.

Feline alimentary lymphoma

Practical relevance Alimentary lymphoma (AL) occurs commonly in cats and exists as distinct subtypes that differ in their clinical course, response to treatment and prognosis. Accurate diagnosis is important to guide appropriate treatment.

Clinical challenges Differentiation of low-grade alimentary lymphoma from lymphoplasmacytic enteritis can be challenging, especially where endoscopic intestinal biopsies, which sample only the mucosa and submucosa, are used. The major differentials for intermediate- and high-grade alimentary lymphoma are other neoplastic and non-neoplastic intestinal mass lesions. The diagnosis of large granular lymphocyte lymphoma requires vigilance as it may be missed with routine diagnostics.

Patient group AL affects predominantly middle- to old-aged domestic crossbred cats (median age 10–13 years).

Evidence base The evidence supporting this review is grade II, III and IV, derived from prospective studies, retrospective case series, reviews, extrapolation from other species, pathophysiological justification and the combined clinical experience of those working in the field.

Feline alimentary lymphoma

Practical relevance Accurate diagnosis of the distinct subtypes of alimentary lymphoma (AL) that occur in cats is important as there are major differences between them in clinical presentation, treatment and prognosis. Unlike intermediate- and high-grade alimentary lymphoma (I/HGAL) and large granular lymphocyte lymphoma (LGLL), which can often be diagnosed by aspiration cytology, full-thickness intestinal biopsies are usually required for the diagnosis of low-grade alimentary lymphoma (LGAL).

Clinical challenges LGAL is an increasingly recognised clinical problem and it can be challenging to differentiate from inflammatory disease. Where there is ambiguity on histology, further diagnostics (immunophenotyping and clonality analysis) may be required. The diagnosis of LGLL requires an index of suspicion as it may be missed with routine diagnostics. While cats with LGAL typically achieve durable remissions with oral prednisolone and chlorambucil, I/HGAL runs a more aggressive clinical course and requires multi-agent chemotherapeutic protocols. Information on the treatment of LGLL is limited and this form of AL has the poorest prognosis. Preliminary studies suggest that abdominal irradiation may potentially be of benefit in cats with AL and further investigations are warranted.

Evidence base The evidence supporting this review is derived from grade II, III and IV prospective studies, retrospective case series, reviews, extrapolation from other species, pathophysiological justification and the combined clinical experience of those working in the field.

Clinical aspects of feline immunodeficiency and feline leukemia virus infection

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses with a global impact on the health of domestic cats. The two viruses differ in their potential to cause disease. FIV can cause an acquired immunodeficiency syndrome that increases the risk of developing opportunistic infections, neurological diseases, and tumors. In most naturally infected cats, however, FIV itself does not cause severe clinical signs, and FIV-infected cats may live many years without any health problems. FeLV is more pathogenic, and was long considered to be responsible for more clinical syndromes than any other agent in cats. FeLV can cause tumors (mainly lymphoma), bone marrow suppression syndromes (mainly anemia) and lead to secondary infectious diseases caused by suppressive effects of the virus on bone marrow and the immune system. Today, FeLV is less important as a deadly infectious agent as in the last 20 years prevalence has been decreasing in most countries.

Abdominal irradiation as a rescue therapy for feline gastrointestinal lymphoma: A retrospective study of 11 cats (2001–2008)

In this retrospective study medical records of 11 cats with gastrointestinal lymphoma were evaluated to determine the efficacy of radiation therapy when used in a rescue therapy setting. All cats had relapsed or resistant lymphoma. Two fractions of radiation were delivered over 2 days for a total of 800 cGy. Acute effects of radiation were not noted, except one cat that had a self-limiting loss of appetite. Response was noted in 10/11 cats. Median survival post-radiation therapy was 214 days and the overall median survival in this study was 355 days. This study suggests that abdominal irradiation for feline gastrointestinal lymphoma was well tolerated and may contribute to a positive clinical response.

Expertise and advocacy in animal-welfare decision making: considerations for a veterinary curriculum in animal welfare

An animal-welfare curriculum for veterinary students should provide learning opportunities in the application of veterinary expertise to patient management and animal-welfare policy. Real-life and hypothetical cases are presented that can allow students to develop their personal-values statement about animal welfare, explore the interaction of facts and values in deciding on a course of action, and understand the unique obligations and authority they will have as veterinarians.