Lymphoma In Cats Research Articles

The diagnostic relevance of mesenteric lymph node biopsy in small intestinal lymphoma in cats.

Regional lymph nodes are frequently sampled in cats with suspected intestinal lymphoma; however, their diagnostic value has not been explored. To investigate whether histologic and immunohistochemical analysis of mesenteric lymph nodes correlates with the diagnosis of intestinal lymphoma in cats. One hundred 2 client-owned cats diagnosed with intestinal lymphoma. Retrospective study. The inclusion criteria required a full-thickness biopsy of the small intestine and concurrent excision of mesenteric lymph nodes. Histologic and immunophenotypic analyses were performed on intestinal biopsies and corresponding lymph nodes. Selected nodal samples diagnosed with reactive lymph nodes underwent clonality testing. Transmural T-cell lymphomas, encompassing small and large cell types, were predominant (64 cases, 62.7%), with large B-cell lymphomas being more frequently transmural (68.8%) than mucosal (31.2%). Among all lymph nodes examined, 44 (43.1%; 95% CI: 33.9%-52.8%) exhibited neoplastic infiltration. Among cases of small cell lymphoma, 51 out of 72 (70.8%; 95% CI: 59.4%-80.1%) showed no nodal involvement. Clonality results correctly identified 19/30 (63.3%; 95% CI: 45.5%-78.2%) reactive lymph nodes. Concerns were raised regarding clonal identification in the remaining cases and potential misdiagnoses based on phenotypic characteristics. The study underscores the potential drawbacks of relying solely on mesenteric lymph nodes for diagnosing intestinal lymphomas in cats, particularly small cell subtypes. It emphasizes the importance of full-thickness biopsies for assessing transmural infiltration and recommends caution when utilizing mesenteric lymph nodes for histologic, immunohistochemical and clonality evaluations in mucosal lymphomas. Despite limitations, this research highlights the need for comprehensive diagnostic strategies in cats with intestinal lymphoma.

Description and Characterization of Different Types of Lymphoma in Cats in Hong Kong.

This study aimed to characterize and describe the different lymphoma types and anatomical forms in cats in Hong Kong. The clinical and histopathological data of cats diagnosed with lymphoma by cytology and/or histopathology were collected from a large diagnostic laboratory in Hong Kong. In total, 444 cats were diagnosed with lymphoma over four years (2019-2022). Like other countries where there is a low prevalence of FeLV infection, the predominant form of lymphoma was gastrointestinal (abdominal). Nasopharyngeal and peripheral nodal lymphoma were the second and third most common forms of lymphoma. The large cell/high-grade lymphoma type was much more common than the low-grade/small cell lymphoma in the study population. Domestic short hair was the most commonly affected breed in our study (n = 259/444). Among the cats with identified T/B-cell status, B-cell lymphoma (n = 61/81) prevailed as the most common phenotype. This study describes and characterizes the different types of feline lymphoma in cats in Hong Kong, adding valuable information to the body of knowledge.

The fecal bacterial microbiota is not useful for discriminating between lymphoplasmacytic enteritis and low-grade intestinal T-cell lymphoma in cats nor for predicting therapeutic response.

To evaluate the fecal bacterial microbiota at the time of diagnosis (T0) and after 1 month of therapy (T1) in cats diagnosed with lymphoplasmacytic enteritis (LPE) or cats with low-grade intestinal T-cell lymphoma (LGITL) and to compare these findings with those of healthy cats. 5 healthy cats, 13 cats with LPE, and 7 cats with LGITL were prospectively enrolled between June 2020 and June 2021. Fecal samples were collected at T0 and T1, and DNA was extracted for 16S ribosomal amplicon sequencing. Alpha diversity and beta diversity were computed. The taxonomic assignment was performed using sequences from the Silva v138 formatted reference database. Differential abundant taxa were selected in each taxonomic level, with the P value adjusted < .05, as the cut-off. No significant differences in alpha and beta diversity were found either at T0 or T1 between healthy and diseased cats or between cats with LPE and LGITL. Beta-diversity analysis showed an increase in the Fusobacteriaceae family in cats with LGITL at T0, compared to cats with LPE. Regardless of histological diagnosis, several microbiota differences were found at T0 based on serum cobalamin levels. Fecal samples were successfully used to characterize the bacteriome of the intestinal tract in cats by 16S rRNA gene sequencing. However, results highlighted that the metagenomic evaluation was not useful to discriminate between LPE and LGITL nor to predict the therapeutic response in this study population.

Лимфома у кота

The purpose of this article is to raise the awareness of veterinary specialists in the field of treatment and prevention of lymphoma in cats, as well as to give an example of the effectiveness of treatment of lymphoma with chemotherapy, according to the modified CHOP protocol.&#x0D; The patient is an 11-month-old half-breed cat. The reason for going to the clinic: lameness for several days and serous discharge from the nose. X-ray examination, computed tomography, cytological analysis using the method of material selection using fine needle biopsy (TIAB), general and biochemical blood tests, rapid test for the presence of leukemia and immunodeficiency viruses (FIV AB/FeLV Ag) were used as methods of diagnosing the disease. The treatment was carried out from the age of 11 months to one year and nine months. The treatment protocol is given in details.&#x0D; The article provides a general information of feline lymphoma, describes its types and clinical picture, recommended treatment regimens and prognosis, provides information on the average life expectancy of cats with lymphoma with timely and prompt treatment.

Treatment of feline intermediate to high-grade alimentary lymphoma: A retrospective evaluation of 55 cats treated with the VAPC combination chemotherapy protocol (2017-2021).

The most commonly utilized protocols to treat lymphoma in cats employ vincristine, cyclophosphamide and prednisone; with additional drugs sometimes used including L-asparaginase and doxorubicin. Medical records were reviewed for 55 cats with alimentary lymphoma treated with a novel multiagent protocol using prednisolone, L-asparaginase, doxorubicin, vinblastine instead of vincristine, a higher dosage of cyclophosphamide and oral procarbazine (VAPC protocol). Outcomes evaluated were response to therapy, toxicity and progression-free survival (PFS). Grade 3 or 4 neutropenia was the most common treatment-related reason for chemotherapy dosage adjustment, occurring in 8 of 52 cats receiving vinblastine, 7 of 55 cats receiving cyclophosphamide and 1 of 40 cats receiving doxorubicin, but febrile neutropenia was identified in only two cats. Of 38 cats receiving chemotherapy for measurable disease, 26 (68.4%) achieved complete response (CR). Three cats achieved a partial response and 9 cats failed to achieve a remission. There were no identified factors influencing whether a cat was likely to achieve CR. For all 55 cats (including those receiving chemotherapy and surgery), median PFS was 184 days with 1, 2 and 3-year survival rates of 35.4%, 26.5% and 26.5%, respectively. On multivariate analysis, 40 cats that achieved CR had a median survival time of 341 days (78 days for PR, 45 days for NR); PFS times were also significantly affected by lymphocyte:monocyte L:M ratio (>3.4 = 700 days vs. ≤3.4 = 126 days) and B-cell versus T-cell phenotype (220 days vs. 42 days, respectively).

Domestic cat hepadnavirus detection in blood and tissue samples of cats with lymphoma

Domestic cat hepadnavirus (DCH), a relative hepatitis B virus (HBV) in human, has been recently identified in cats; however, association of DCH infection with lymphoma in cats is not investigated. To determine the association between DCH infection and feline lymphoma, seven hundred and seventeen cats included 131 cats with lymphoma (68 blood and 63 tumor samples) and 586 (526 blood and 60 lymph node samples) cats without lymphoma. DCH DNA was investigated in blood and formalin-fixed paraffin-embedded (FFPE) tissues by quantitative polymerase chain reaction (qPCR). The FFPE lymphoma tissues were immunohistochemically subtyped, and the localization of DCH in lymphoma sections was investigated using in situ hybridization (ISH). Feline retroviral infection was investigated in the DCH-positive cases. DCH DNA was detected in 16.18% (11/68) (p = 0.002; odds ratio [OR], 5.15; 95% confidence interval [CI], 2.33–11.36) of blood and 9.52% (6/63) (p = 0.028; OR, 13.68; 95% CI, 0.75–248.36) of neoplastic samples obtained from lymphoma cats, whereas only 3.61% (19/526) of blood obtained from non-lymphoma cats was positive for DCH detection. Within the DCH-positive lymphoma, in 3/6 cats, feline leukemia virus was co-detected, and in 6/6 were B-cell lymphoma (p > 0.9; OR, 1.93; 95% CI, 0.09–37.89) and were multicentric form (p = 0.008; OR, 1.327; 95% CI, 0.06–31.18). DCH was found in the CD79-positive pleomorphic cells. Cats with lymphoma were more likely to be positive for DCH than cats without lymphoma, and infection associated with lymphoma development needs further investigations.

Clinical characterisation and long-term survival of paediatric and juvenile lymphoma in cats: 33 cases (2008-2022).

The aims of this study were to describe the clinical presentation, tumour characteristics, responses to chemotherapy protocols and toxicity in a cohort of cats with lymphoma up to 18 months of age. In addition, the probability of long-term (>2 years) survival was explored. The medical records of client-owned cats aged up to 18 months diagnosed with lymphoma between 2008 and 2022 at five UK-based veterinary referral hospitals were reviewed. Thirty-three cats were included. The most common anatomical forms were mediastinal (42%), disseminated disease (30%) and renal (15%), with all cats having intermediate to large cell lymphoma. Three out of 29 cats tested were positive for FeLV but none for FIV. Twenty-six cats were treated with multi-agent chemotherapy protocols with complete and partial responses seen in 46% and 50% of cats, respectively. For this group, median progression-free survival was 133 days (95% confidence interval [Cl] 67 to 199) and median survival time was 268 days (95% Cl 106 to 430). Complete response to chemotherapy was associated with a longer progression-free survival. Seven cats were considered long-term survivors (>2 years). Chemotherapy was generally well tolerated with none of the long-term survivors suffering from chronic sequelae from cytotoxic treatment. Paediatric and juvenile cats with lymphoma showed a high response rate to multi-agent chemotherapy protocols with rare significant toxicities. The presence of long-term survivors may suggest a more favourable outcome in a subset of patients.

Toxicity of Etopozid in the treatment of cats with lymphoma

Lymphoma in cats is a malignant neoplasm of lymphoid tissue (lymphocytes and other cells of the defense system are affected). Causes of lymphoma in cats can vary, including genetic factors, viruses, and exposure to carcinogens. Most often, patients are admitted to an appointment already with an advanced stage of lymphoma, since the signs of oncological disease are nonspecific and can be easily confused with other diseases of the gastrointestinal tract. Symptoms in cats may include swollen abdominal lymph nodes, decreased appetite and loss of lean body mass, behavioral changes (lethargy, weakness), vomiting, and fever. Lymphoma in cats accounts for 50-90% of all formations of the hematopoietic system. Chemotherapy is one of the main treatments. It consists in the use of cytostatics that inhibit the growth and division of tumor cells. Increasingly, new protocols are being tested in the treatment of animals for various oncological diseases. The length of the chemotherapy protocol varies according to the stage of the disease, clinical manifestation and extent of the lesion, but the most effective chemotherapy protocol is CHOP (endoxan, doxorubicin, vincristine, prednisolone), which is designed for 25 weeks in cats. There are data on the use of the drug etoposide not only in humans but also in animals, which can be effective and serve as a replacement for endoxan in the CHOP treatment protocol. But in addition to the main methods of treatment, it is important to monitor the general condition of the animal, since the main goal of chemotherapy is to prolong the normal quality of life of the animal.

Comparative effectiveness of conservative treatment regimens for alimentary lymphoma in cats

Lymphoma is the most common malignant neoplasm in cats. Without treatment, mortality is about 40-75% within 4-8 weeks after diagnosis. In this regard, this pathology requires chemotherapy in almost all cases. The aim of the work is to compare the effectiveness of conservative treatment regimens for alimentary lymphoma in cats. The objects of the study were cats of different breeds with an established diagnosis of alimentary lymphoma aged from 2 to 16 years, with an average live weight at the time of admission of 3.9 kg. To conduct a comparative analysis of the conservative treatment of alimentary lymphoma, experimental groups were compiled: I (n=10) – patients with I/HGAL receiving treatment according to the CHOP protocol, II (n=10) - patients with I/HGAL receiving treatment according to the COP protocol. The therapeutic efficacy of the applied conservative treatment regimens was 80% for both groups. The median survival in the 1st experimental group was 60% higher and amounted to 452.10±201.26 days versus 282.00±110.90 days in the second experimental group. Long-term results were better for patients in the first group: survival rate of more than 1 year is 60% in the first group and 30% in the second group, more than 2 years is 30% in the first group and 0% in the second group. The frequency of moderate complications was higher for 1 experimental group, and severe complications were observed with the same frequency in both groups. It follows from this that the toxicity of the CHOP protocol is undoubtedly higher than COP.

A Monte Carlo study on dose distribution of an orthovoltage radiation therapy system.

It is important to plan radiotherapy treatment and establish optimal dose distribution to reduce the chances of side effects and injury. Because there are no commercially available tools for calculating dose distribution in orthovoltage radiotherapy in companion animals, we developed an algorithm to accomplish this and verified its characteristics using tumor disease cases. First, we used the Monte Carlo method to develop an algorithm to calculate the dose distribution of orthovoltage radiotherapy (280 kVp; MBR-320, Hitachi Medical Corporation, Tokyo, Japan) using BEAMnrc at our clinic. Using development of Monte Carlo method, dose distribution for tumor and normal organs were evaluated in brain tumors, squamous cell carcinomas of the head, and feline nasal lymphomas. In all cases of brain tumors, the mean dose delivered to the GTV ranged from 36.2 to 76.1% of the prescribed dose due to the decrease through the skull. In the nasal lymphoma in cats, the eyes with covered a 2mm-thick lead plate, the respective average dose to the eyes was 71.8% and 89.9% less than that to the uncovered eyes. The findings may be useful for informed decision making in orthovoltage radiotherapy with more effective and targeted irradiation and data collection allowing detailed informed consent.

Pathomorphology of the renal form of lymphoma in cats

Lymphoma is one of the most common neoplasias in cats, affecting various organs and tissues. Extranodal lymphoma is characterized by local damage to such organs as the nose, eyes, skin, central nervous system, and kidneys. Cats usually have bilateral kidney damage with possible metastatic damage to the liver and lungs. Statistically, the extranodal type of lymphoma, namely the renal form, is found in 7% to 30% of cases, mainly in cats older than five years. Clinical signs of renal lymphoma are non-specific and variable, typical for acute renal failure, and manifest themselves through general exhaustion, polyuria, polydipsia, and renomegaly. In most cases, the prognosis for lymphoma in cats is cautious. The article describes two clinical cases of outbred cats with a primary renal form of lymphoma. In both cases, the cats were clinically diagnosed with acute kidney injury and treated symptomatically. An ultrasound examination of the cats’ kidneys revealed a sharp increase in their volume and increased echogenicity of the cortical layer with a fine-grained and nodular structure. The cytological picture in fine-needle aspirates from the kidneys was characterized by a massive monomorphic population of lymphoblasts, which exceeded erythrocytes by 2–3 times in diameter. The cytoplasm of the lymphoblastic cells was sparse with large round nuclei with dense chromatin. The cells were mostly uninucleate, with atypical mitoses and moderate cellular atypism. Epithelial cells, which were occasionally visualized between large lymphoblastic cells, had broad vacuolated cytoplasm and a large round nucleus. Express tests for feline leukemia virus showed negative results. Both cats died 7 and 10 days after initiation of treatment, respectively. During the autopsy, sharply enlarged and deformed kidneys were recorded, and the border between the cortical and medullary substances was difficult to differentiate. Irregularly shaped, white tumorous formations were visualized in the cortical layer. Diffuse infiltration of the kidneys’ cortical layer with large monomorphic lymphoblastic elements with large hyperchromic nuclei and narrow cytoplasm was noted histologically. Lymphoblastic cells in a state of vacuolar and hydropic dystrophy were located between the proximal and distal tubules. The lumens were filled with protein mass and desquamated epithelium. The capsule of the kidney glomeruli was slightly thickened and the vessel walls were soaked with plasma proteins. Immunohistochemically, intensive expression of the CD79a marker and high expression of the Ki-67 marker were detected in the examined kidney samples, which indicates the development of diffuse B-cell lymphoma with an unfavourable prognosis.

B-mode ultrasound and colour Doppler findings in cats with gastric lymphoma.

The purpose of this study was to describe B-mode and colour Doppler ultrasound (US) features of gastric lymphoma in cats. Cats with histopathological or cytological confirmation of gastric lymphoma that underwent abdominal US were included in this retrospective study. Clinical signs were recorded and radiographs reviewed when available. Gastric lesions were ultrasonographically evaluated for location, distribution, wall layering, echogenicity and thickness. Colour Doppler assessment was based on vessels, location and direction. Forty-five cats were included. All presented with vomiting, 7/45 (15.5%) with haematemesis. Radiographs were available in 27/45 cases, and demonstrated a gastric mass in 19/27 (70.4%) cases. The most common US appearance was transmural wall thickening with absent layering 42/45 (93.3%) and hypoechogenicity 39/45 (86.7%). Median maximum thickness was 2.1 cm. Ulceration or erosion was suspected in 23/45 (51%) cases, two of which perforated. Colour Doppler images were available in 33/45 cases. The most common Doppler finding was transmural vessels coursing perpendicularly to the lumen in 14/33 (42.4%). Abdominal effusion was uncommon (n = 11/45; 24.4%). Regional lymphadenopathy was frequent, observed in 44/54 lymph nodes reviewed on US, and US suspicion of splenic, hepatic and intestinal lymphomatous infiltration was reported in 24/45 (53.3%) cases. The most common US appearance of gastric lymphoma was transmural hypoechoic segmental wall thickening with layering loss. Location and distribution were variable. Colour Doppler displayed increased blood supply with a predominant pattern of perpendicular vessels, possibly representing aberrant arteries originating from subserosal and submucosal plexus. Lymphomatous infiltration of lymph nodes and other abdominal organs was frequent, confirming local and distant aggressiveness of gastric lymphoma in cats. Vomiting and haematemesis were frequently associated with the suspicion of ulcer on US. Perforation was a rare occurrence.

Characteristics of functional and laboratory parameters in alimentary lymphoma in cats

Gastrointestinal or alimentary lymphoma is the most common primary malignant neoplasm of the gastrointestinal tract in cats. The aim of the work is to study the pathogmonicity of functional and laboratory parameters in alimentary lymphoma in cats. The objects of the study were cats of different breeds, the age ranged from 2 to 16 years, the average live weight at the time of admission was 3.9 kg with pronounced gastroenterological disorders. Two groups of cats were created for the study: 1st – control (healthy individuals; n= 10), 2nd – experimental (sick individuals; n= 20). All cats were subjected to standard clinical examination by general methods - examination, palpation, auscultation, thermometry. Anamnesis was carefully collected and general (hematological analyzer URIT-2800Vet) and biochemical (automatic biochemical analyzer IDEXX Catalist) blood tests and additional research methods were performed. Gastrointestinal lymphomas are the leaders – 79% of all lymphomas. The vast majority of cats had progressive weight loss, hypo- and anorexia, vomiting, diarrhea. Solid neoplasms in the abdominal cavity were palpated only in 11 cats. In the general blood test, erythrocytes in the experimental group are lower than in the control group (6.23±0.28x1012/l versus 8.40±0.81x1012/l; P&lt;0.01); the level of leukocytes in the experimental group is 78% higher than in the control group (P&lt;0.001); the number of lymphocytes is higher in the experimental group by 74.3% (P &lt;0.001); monocytes were higher in the experimental group - 7.21 ±0.39% versus 4.0±1.05% (P &lt;0.01). Biochemical blood analysis showed that the studied parameters in sick cats are mainly within the reference values. The level of urea is higher in sick cats by 38.71% (P &lt;0.05), AST by 88.79%. As the most pronounced clinical signs of alimentary lymphoma, hypo- and anorexia, progressive weight loss, vomiting, diarrhea can be distinguished, from laboratory indicators - a decrease in the number of red blood cells, an increase in the number of leukocytes, including monocytes, an increase in urea levels.

Ultrasonographic and pathomorphological changes in Alimentary Lymphoma in cats

The study aimed to determine the characteristic changes in alimentary lymphoma in cats during ultrasonography, pathoanatomic and cytological examination of biopsy material. The survey objects are cats with gastroenterological disorders with suspected alimentary lymphoma of different ages and genders. The diagnosis was made based on a clinical examination according to generally accepted methods, laboratory blood examination, ultrasound examination, pathomorphological examination of the intestinal walls and lymph nodes, and cytological examination of the lymph node material obtained by the TIAB method. The authors carried out the material sampling for cytological examination using percutaneous fine needle aspiration (FNA) biopsy under ultrasound control on the Mindray Z6 Vet apparatus. In addition, the authors conducted pathological and cytological studies in the Vet Union laboratory. When analyzing ultrasound examination in cats diagnosed with alimentary lymphoma, hepatomegaly, 1% ascites, 3% hydrothorax, 3 % increase in mediastinal lymph nodes, 7% splenomegaly, 16% violation of differentiation of intestinal layers, 16% violation of differentiation of intestinal layers, 29% increase in mesenteric lymph nodes, 29 % thickening of intestinal walls were observed in 12% of cases. Cytological examination revealed rounded, large, separately located cells. The population is monomorphic. During a histological study in the intestinal wall, adjacent fatty tissue of the omentum, and lymph node tissue, there is a highly cellular invasive formation constructed from diffuse layers of rounded lymphoid neoplastic cells with a scanty fibrous stroma. The most characteristic ultrasound findings are the thickening of the intestinal walls and an increase in mesenteric lymph nodes.

Ультрасонографические предпосылки и обоснование стадий развития лимфомы кишечника у кошек

According to the literature, intestinal lymphoma is currently the most common tumor disease of the digestive canal in cats and is characterized by a severe course and poor response to chemotherapy. Because this tumor shares clinical and ultrasound characteristics with inflammatory bowel disease, diagnosis is challenging and requires a number of complex procedures that often cannot be performed without sedating the animal. In connection with the above, the purpose of this work was to identify ultrasonographic prerequisites for intestinal lymphoma in cats and substantiate the stages of development of intestinal lymphoma in cats. The objects of the research were cats of various breeds (34 animals in total), various sex and age groups. All animals underwent a clinical examination using standard methods, as well as ultrasonographic examination of the abdominal cavity. Ultrasound studies revealed such changes as thickening of the intestinal wall, a change in the ratio of layers with partial or complete loss of differentiation of the intestinal layers, a decrease or increase in the echogenicity of the layers of the intestinal wall, heterogeneity of the echostructure, deformation of the lumen with the presence of heterogeneous anechoic contents, impaired peristalsis, a local increase in the echogenicity of the surrounding fatty tissue. tissue, pronounced enlargement of lymph nodes with changes in their echostructure and echogenicity, the presence of free fluid in the abdominal cavity. The diagnosis was confirmed using cytological and histological studies.

Clinical and magnetic resonance imaging features, and pathological findings of spinal lymphoma in 27 cats.

This multicentric retrospective study describes the clinical and MRI features and pathological studies of spinal lymphoma in 27 cats. MRI characteristics and their possible correlations with histopathological findings were studied. The most frequent neurological signs were rapidly progressive paraparesis (62.9%) or paraplegia (22.2%). Bimodal age distribution was found with 40.7% of cats aged ≤2.5 years (63.6% of them FeLV positive), and 44.4% of cats aged ≥8 years (16.7% of them FeLV positive). Spinal lymphoma was generally presented on MRI as an ill-defined epidural focal lesion with moderate to severe spinal cord compression, expanding more than one vertebral body. MRI lesions were typically localized in the lumbar vertebral segment (p = 0.01), circumferential to the spinal cord (p = 0.04), hyperintense on T2-weighted sequences (p = 4.3e-06), and isointense on T1-weighted sequences (p = 8.9e-07). The degree and pattern of contrast enhancement were variable. Other morphological patterns included paravertebral masses with extension into the vertebral canal and lesions centered in the spinal nerve roots. Involvement of vertebrae and adjacent spinal soft tissues was present in 74% of cases when present vertebral involvement was characterized by cortical sparing. When follow-up MRI studies (n = 4) were performed after treatment new lesions of similar nature but different localizations and extension were observed. Confirmation of spinal lymphoma was performed by CSF analysis in 4/27 (14.8%) of cases, by FNA in 6/27 (22.2%) of cases, by surgical biopsy in 10/27 (37%) of cases, by FNA and surgical biopsy in 1/27 (3.7%) of cases, by CSF, FNA, surgical biopsy and postmorten examination in 1/27 (3.7%) of cases, and postmorten studies in 5/27 (18.5%) of cases. Antemortem diagnosis was achieved in 22/27 (81.5%) cats. The presence of necrosis in histopathological studies as an unfavorable prognostic indicator of survival was significantly more probable when lesions were not hyperintense on T2-weighted sequences (p = 0.017). Spinal lymphoma in cats is a complex entity with heterogeneous imaging and histopathological appearance. However, certain MRI features may support a tentative diagnosis, which in a group of cases can be confirmed when combined with the CSF findings. For the rest of the cases, tissue sampling assisted by imaging findings remains necessary for definitive diagnosis.

Feline lymphoma of the nervous system. Immunophenotype and anatomical patterns in 24 cases.

This study aimed to describe the specific localization and anatomical pattern of 24 feline lymphomas of the nervous system for which the immunophenotype was identified by immunohistochemistry investigations to support the potential specific correlation between subtypes and anatomical patterns. In total 10 tumors affected the spinal cord, eight the brain, four the peripheral nerves, one involved both the brain and the spinal cord, and one simultaneously the brain and the optic nerves. Twenty two tumors were primary lymphomas. The affected animals were 8 years of mean age. Tumors developed as an extra-axial mass (11 cases), intra-axial mass (six cases), leptomeningeal lymphomatosis (three cases), and neurolymphomatosis (five cases). One of them expressed both leptomeningeal lymphomatosis and neurolymphomatosis patterns. Two intra-axial brain lymphomas showed an angiotropic pattern. The optic chiasm was the most involved site for neurolymphomatosis. Immunolabeling was performed using anti-CD3, CD20, CD79a, PAX5, MUM-1, CD56, and anti-CD44 antibodies. In total, 12 tumors consisted of B cell lymphomas, and six of T cell lymphomas, two cases were double-reactive lymphomas while two cases consisted of non-B non-T lymphomas. B cell lymphoma affected animals of 6.4 years of mean age, while the T cell lymphoma affected older animals (mean age of 11.1 years). Extra-axial tumors mainly consisted of B cell lymphomas (8/11). Neurolymphomatosis expressed different immunophenotypes, and the B cell phenotype was the most prevalent in the optic chiasm. Two leptomeningeal lymphomatoses expressed T cell immunophenotype. For the first time, plasmacytoid differentiation was found for angiotropic lymphoma and neurolymphomatosis. All the cases, except one, were CD56-negative. CD44-expression confirmed a common malignant potential for all the anatomical patterns of the nervous system lymphoma in cats. Immunophenotype of feline lymphoma of the nervous system and its potential association with specific anatomical patterns should be strongly required in the diagnostic workup and clinical approach to this tumor especially when its primary origin is confirmed.

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 nervous system lymphoma in cats.

Here we characterize the neuroanatomic distribution, neuropathology, and immunophenotype of 10 cases of primary nervous system lymphoma in cats. Cases were retrospectively searched from 2 academic institutions. Selected cases were reviewed and subjected to immunohistochemistry (IHC) for CD3, CD20, and Pax5. The mean age of affected cats was 9.1 y, and no sex or breed predilection was observed. The most common clinical sign was ataxia (8 cases). Gross changes reported in 8 cases consisted of white-to-tan masses (7 cases) or swelling (1 case) within the neuroparenchyma (5 cases) or epidural spaces (3 cases). Histologically, intraparenchymal lymphomas occurred in the gray and white matter or perivascular spaces (7 cases); extraparenchymal lymphomas (6 cases) consisted of neoplastic cell infiltration of the perivascular spaces in the leptomeninges, choroid plexus, or epidural spaces. Nerve lymphomas were diffusely infiltrative. Tumors occurred in the brain (4 cases), spinal cord and nerves (3 cases), spinal cord (2 cases), and brain, spinal cord, and nerves (1 case). IHC was consistent with a B-cell lymphoma in 5 cases and with a T-cell lymphoma in 5 cases.

Outcome of stereotactic body radiation for treatment of nasal and nasopharyngeal lymphoma in 32 cats.

BackgroundThe safety and efficacy of stereotactic body radiation therapy (SBRT) in the treatment of localized nasal lymphoma in cats has not been described.HypothesisStereotactic body radiation therapy with or without adjuvant chemotherapy is an effective and well‐tolerated treatment for localized nasal lymphoma in cats.AnimalsThirty‐two client owned cats referred to Colorado State University for the treatment of nasal lymphoma.MethodsRetrospective study of cats treated with SBRT between 2010 and 2020 at Colorado State University. Diagnosis of nasal lymphoma was obtained via cytology or histopathology. Signalment, radiation protocol, concurrent treatments, adverse effects, and survival were recorded.ResultsProgression free survival was 225 days (95% CI 98–514) and median survival time (MST) was 365 days (95% CI 123–531). No significant difference in survival was identified between cats that received 1 versus greater than 1 fraction (MST 427 vs. 123 days, P = 0.88). Negative prognostic factors included cribriform lysis (MST 121 vs. 876 days, P = 0.0009) and intracalvarial involvement (MST 100 vs. 438 days, P = 0.0007). Disease progression was noted in 38% (12/32), locally in 22% (7/32), and systemically in 16% (5/32). No cats developed acute adverse effects. Ten cats developed late adverse effects: keratitis/keratitis sicca (n = 2), alopecia (n = 4), and leukotrichia (n = 4). Twenty‐four cats (75%) had signs consistent with chronic rhinitis.ConclusionsSBRT is effective and well tolerated for treating localized nasal lymphoma in cats. Outcomes for cats with lower stage disease (canine modified Adam's stage 3 and lower) are comparable to historic data of cats treated with fractionated radiation therapy.