Cutaneous Epitheliotropic T-cell Lymphoma Research Articles

Clinical response to oclacitinib in canine cutaneous epitheliotropic T-cell lymphoma: A case reports

Clinical response to oclacitinib in canine cutaneous epitheliotropic T-cell lymphoma: A case reports

Efficacy of verdinexor for the treatment of naïve canine epitheliotropic cutaneous T-cell lymphoma: An open-label pilot study.

Verdinexor (Laverdia-CA1; Dechra Veterinary Products), a selective inhibitor of nuclear export, has been utilised for treatment of non-Hodgkin T-cell lymphoma in dogs. However, the efficacy of verdinexor has not been evaluated for cutaneous epitheliotropic T-cell lymphoma (CETL). To evaluate the efficacy of verdinexor for the treatment of CETL. Eight client-owned animals with CETL. Patients received between 1.28 and 1.45 mg/kg verdinexor per os twice weekly with a minimum of 72 h between doses until disease progression or voluntary withdrawal. Adjunctive therapy with lokivetmab or prednisone was permitted after Day (D)14. Assessment of clinical lesions (canine Response Evaluation Criteria in Solid Tumors [cRECIST v1.0] and novel Canine Epitheliotropic Lymphoma Extent and Severity Index [CELESI]), pruritus (Visual Analog Scale) and treatment efficacy (owner global assessment of treatment efficacy [OGATE]) were evaluated every 14 days for 3 months, then monthly thereafter (mean 70 ± 43.4 days). Seventy-five percent of patients achieved complete response, partial response or stable disease. The mean time to disease progression was 56 ± 41 days. There was a significant reduction (p = 0.026) in total CELESI score when the lowest score for each dog was compared to their score at D0. Verdinexor did not significantly reduce pruritus at any time point (p = 0.45), including when given as a monotherapy or concurrently with lokivetmab ± glucocorticoids. On D28, 75% of owners rated response to treatment as 'fair' to 'excellent'. The most common adverse effects included weight loss, inappetence, vomiting and lethargy. Verdinexor could be considered a safe, palliative treatment for canine CETL.

Diascopy and histopathological evaluation of nonblanching erythematous dermatoses in dogs.

Diascopy is a point-of-care diagnostic test used to differentiate skin erythema due to vascular dilation from haemorrhage. In the veterinary literature, only a handful of diseases have been described to be associated with a negative (nonblanching) diascopy result, and histological investigation of haemorrhage has been inconsistent. Retrospective study to undertake a histopathological investigation of canine, nonblanching erythematous dermatoses for the presence or absence of haemorrhage and vascular changes. Skin biopsies from dogs presented with moderate-to-severe nonblanching erythema were evaluated histologically. Additionally, clinical data about each patient were analysed. Twenty cases were identified with nonblanching erythema. Diagnoses included vasculopathy (n = 6), canine eosinophilic dermatitis (n = 3), cutaneous epitheliotropic T-cell lymphoma (n = 2), and one case each of sterile granuloma and pyogranuloma syndrome, German shepherd dog pyoderma, multiple mast cell tumours, haemangiosarcoma, exfoliative cutaneous lupus erythematosus, canine leishmaniosis with sebaceous adenitis, sebaceous adenitis with concurrent dermatophytosis, calcinosis cutis and canine atopic dermatitis with insect-bite reaction. One or more vascular changes were present in all 20 cases and included perivascular oedema, endothelial swelling and neutrophilic infiltration of vessel walls. Haemorrhage was identified in 17 of 20 cases (85%). Three cases without dermal haemorrhage were calcinosis cutis, sebaceous adenitis with dermatophytosis and canine atopic dermatitis with insect-bite reaction. Negative diascopy was associated with haemorrhage and vascular pathological findings in the majority of cases, yet not all. Haemorrhage was identified histologically in all diseases previously reported as nonblanching as well as in a few additional diseases.

Clinical efficacy of recombinant canine interferon-gamma therapy in dogs with cutaneous epitheliotropic T-cell lymphoma.

The antitumour effects of interferon-gamma (IFN-γ) in humans with cutaneous epitheliotropic T-cell lymphoma (CETCL) have been described; however, the efficacy of IFN-γ in dogs has not been investigated. The aim of this study was to evaluate the efficacy of recombinant canine IFN-γ (rCaIFN-γ) therapy in dogs with CETCL. Twenty dogs with CETCL recruited from seven veterinary clinics were enrolled in the study. Fifteen dogs were treated with rCaIFN-γ, and five control dogs were treated with prednisolone. We evaluated survival time, skin lesions (erythema, nodules, ulcers and bleeding), pruritus and general condition (sleep, appetite and body weight). In the rCaIFN-γ group, a questionnaire regarding the therapy was administered to owners after the dogs died. No significant differences existed in the median survival time between the rCaIFN-γ and control groups (log-rank test: p=0.2761, Wilcoxon's rank sum test: p=0.4444). However, there were significant differences in ulcer, bleeding, pruritus, sleep, appetite and body weight between the groups (Wilcoxon-Mann-Whitney U-test: p=0.0023, p=0.0058, p=0.0005, p=0.0191, p=0.0306 and p=0.0306, respectively). Two (40%) of five dogs were euthanised in the control group, compared with none in the rCaIFN-γ group. Fourteen questionnaires were collected, and owners reported that they were satisfied with the rCaIFN-γ treatment. Although the median survival time was not prolonged, rCaIFN-γ could be helpful in maintaining good quality of life for dogs with CETCL.

Prognostic clinical and histopathological features of canine cutaneous epitheliotropic T-cell lymphoma.

Canine cutaneous epitheliotropic T-cell lymphoma is a neoplasm with heterogeneous clinical and histopathological presentations. Survival times and responses to therapy are variable, and indicators to predict outcomes are lacking. Clinical and histopathological parameters from 176 archival cases from the University of Pennsylvania and University of Bern (2012-2018) were investigated for associations with clinical outcomes. Histopathological evaluation used digitized whole slide images and QuPath software. Cases included 107 female and 69 male dogs from 48 breeds, with a mean age of 10.4 years. Most common clinical signs were erythema (n = 131), crusting (n = 108), and scaling (n = 102). Affected sites were haired skin (n = 159), lip (n = 74), nasal planum (n = 49), and paw pads (n = 48). The median survival time (MST) was 95 days (1-850). Dogs had 4.26-fold and 2.82-fold longer MST when treated with chemotherapy and prednisone, respectively, than when receiving supportive care. Haired skin involvement (hazard ratio [HR]: 2.039, 95% confidence interval [CI]: 1.180-3.523), erosions/ulcers (HR: 1.871, 95% CI: 1.373-2.548), nodules (HR: 1.496, 95% CI: 1.056-2.118), and crusting (HR: 1.454, 95% CI: 1.061-1.994) were clinical parameters predicting poor outcomes, whereas complete posttherapeutic clinical remission (HR: 0.469, 95% CI: 0.324-0.680) and a stable disease (HR: 0.323, 95% CI: 0.229-0.456) were associated with longer survival. Histopathological features associated with the increased risk of death were extensive infiltration of the panniculus (HR: 2.865, 95% CI: 1.565-4.809), mitotic count ≥7/high-power field (HR: 3.027, 95% CI: 2.065-4.439), cell diameter ≥10.0 µm (HR: 2.078, 95% CI: 1.281-3.372), and nuclear diameter ≥8.3 µm (HR: 3.787, 95% CI: 1.647-8.707).

Cutaneous epitheliotropic T-cell lymphoma in ferrets (Mustela putorius furo): 3 cases (2014–2021)

Background : Tumours are commonly encountered in ferrets and lymphoma is the third most common neoplasm in this species. Cutaneous epitheliotropic lymphoma has rarely been described in ferrets. Materials and methods : Inclusion criteria for ferrets in this study were cutaneous lymphoma diagnosed by histopathologic examination. Data collection from affected ferrets presented at the clinic between January 2014 and March 2021 included signalment, medical history, clinical signs, histopathology and immunohistochemistry results, treatments and clinical outcome when available. Results : Three ferrets met the inclusion criteria. They presented with erythematous and crusted lesions on the foot in ferrets 1 and 2, and multiple erythematous papules over the lumbar region in ferret 3. Epitheliotropic T-cell lymphoma was identified by immunohistochemistry in all cases. Chemotherapy was declined in ferret 1 and a medical treatment based on prednisolone, a skin ointment, and spirulina was initiated. Ferret 2 received lomustine and prednisolone. Ferret 3 received chlorambucil, an isotretinoin skin ointment and prednisolone. In all cases, dermatologic symptoms significantly improved or disappeared after 1 to 3 months. Ferret 1 was lost to follow up after 2 months. Ferret 2 discontinued chemotherapy after 7 months and was humanely euthanised 3 months later after recurrence and worsening of its general condition. Ferret 3 died 3 months after diagnosis from an unknown cause. Conclusion and clinical relevance : This case series describes three cases of cutaneous epitheliotropic T-cell lymphoma, with three different treatment plans and illustrates the importance of considering cutaneous epitheliotropic lymphoma as a differential diagnosis in ferrets with dermatologic symptoms.

Evaluation of clonality from multiple anatomic sites in canine epitheliotropic T cell lymphoma.

Canine epitheliotropic cutaneous T-cell lymphoma (eCTCL) is thought to represent a disease homologue to human mycosis fungoides (MF). In human MF, neoplastic cells are phenotypically consistent with resident effector memory T cells, a population that remains for an extended period within tissue without circulating. Dogs with eCTCL often present with lesions in multiple locations, raising the question of whether the neoplasm is of the same T-cell subpopulation or not. To characterize the antigen receptor gene rearrangements of lymphocytes from skin and blood of dogs with eCTCL to determine if neoplastic clones are identical. Fourteen dogs with eCTCL. Histological and immunohistochemical examination, and PCR for antigen receptor rearrangement (PARR) for T-cell receptor gamma (TRG) performed on multiple cutaneous biopsy samples and blood. All skin biopsies contained cluster of differentiation (CD)3-positive neoplastic lymphocytes. Within individual dogs, all skin biopsies revealed identical TRG clonality profiles, suggesting that the same neoplastic clone was present in all sites. In the blood, a matching clone was found in six of 14 dogs, a unique clone was observed in nine of 14 dogs, and no clone was detected in two of 14 dogs. These findings show that canine eCTCL lesions in multiple locations harbour the same neoplastic clone, neoplastic lymphocytes do not remain fixed to the skin and instead can circulate via blood, differing clones can be identified in skin versus blood, and circulating neoplastic cells can be detected without lymphocytosis.

Cutaneous epitheliotropic T-cell lymphoma in a donkey – a case report

BackgroundCutaneous epitheliotropic T-cell lymphoma is a malignant tumour of the skin already reported in humans, dogs, cats, horses, and other species, but not previously in donkeys. The standard diagnosis is based on clinical, morphological and immunophenotypic data. Differentiation of malignant versus benign proliferation of lymphocytes is crucial; in ambiguous cases T-cell receptor gamma (TRG) molecular clonality should be tested. In the present paper, we report a case of mycosis fungoides diagnosed in a donkey whose diagnosis was based on clinical, histological and immunohistochemical aspects and a positive TRG clonality test.Case presentationA twenty-five-year-old donkey gelding was referred with a mildly pruritic, generalised and severe exfoliative dermatosis. Otherwise, the animal was clinically healthy, though mildly underweight. Dermatological examination revealed severe generalised alopecic and exfoliative dermatitis, occasionally eroded, with high number of large, thin, greyish scales. All mucocutaneous junctions except the hoofs were affected. Ectoparasites and dermatophytes were ruled out. The complete blood count and blood smear evaluation revealed mild normocytic normochromic anemia. The biochemistry panel showed mild hyperproteinemia with albumin within the normal range. Protein electrophoresis showed moderate polyclonal hypergammaglobulinemia. Histological findings were characterised by interface dermatitis with massive exocytosis in the epidermis of a homogenous population of lymphoid cells showing atypia. Clusters of neoplastic cells were present within the epidermis forming Pautrier “microabscesses”. These findings are consistent with cutaneous epitheliotropic lymphoma. Immunohistochemical staining revealed uniform labelling of the neoplastic cells for CD3, and lack of expression of CD20 (a B cell lineage associated marker). Molecular clonality PCR (PARR) was performed using equine TRG primers; this revealed a clonal rearrangement in a heavy polyclonal background. Transmission electronic microscopy showed multiple lymphocytes with convoluted or cerebriform nuclei.ConclusionsThis case report provides the first evidence of clinical, histopathological, immunophenotypic features, electron microscopy findings and molecular analysis of a cutaneous epitheliotropic T-cell lymphoma (mycosis fungoides) in a donkey. Our observations suggest that cutaneous T-cell lymphoma should be included in the differential diagnoses of exfoliative dermatitis, even those progressing in a chronic pattern and/or with few or no pruritus.

Cutaneous epitheliotropic T-cell lymphoma with Sézary syndrome in a dog

Cutaneous epitheliotropic T-cell lymphoma with Sézary syndrome in a dog

Transcriptional Differences between Canine Cutaneous Epitheliotropic Lymphoma and Immune-Mediated Dermatoses.

Canine cutaneous epitheliotropic T-cell lymphoma (CETL) and immune-mediated T-cell predominant dermatoses (IMD) share several clinical and histopathological features, but differ substantially in prognosis. The discrimination of ambiguous cases may be challenging, as diagnostic tests are limited and may prove equivocal. This study aimed to investigate transcriptional differences between CETL and IMD, as a basis for further research on discriminating diagnostic biomarkers. We performed 100bp single-end sequencing on RNA extracted from formalin-fixed and paraffin-embedded skin biopsies from dogs with CETL and IMD, respectively. DESeq2 was used for principal component analysis (PCA) and differential gene expression analysis. Genes with significantly different expression were analyzed for enriched pathways using two different tools. The expression of selected genes and their proteins was validated by RT-qPCR and immunohistochemistry. PCA demonstrated the distinct gene expression profiles of CETL and IMD. In total, 503 genes were upregulated, while 4986 were downregulated in CETL compared to IMD. RT-qPCR confirmed the sequencing results for 5/6 selected genes tested, while the protein expression detected by immunohistochemistry was not entirely consistent. Our study revealed transcriptional differences between canine CETL and IMD, with similarities to human cutaneous lymphoma. Differentially expressed genes are potential discriminatory markers, but require further validation on larger sample collections.

Cutaneous epitheliotropic T-cell lymphoma in a dog observed during treatment for iatrogenic Cushing disease which was removed by surgical resection

Cutaneous epitheliotropic T-cell lymphoma in a dog observed during treatment for iatrogenic Cushing disease which was removed by surgical resection

Clinical response to isotretinoin and interferon-\u03b1 of two dogs with cutaneous epitheliotropic T-cell lymphoma: a case report

BackgroundThere is no specific therapy for cutaneous epitheliotropic T-cell lymphoma (CETL). The administration of retinoids in conjunction with interferon-α (IFN-α) in CETL has not been reported in dogs.Case presentationTwo dogs (Shih tzu and Miniature pinscher) presented with multiple nodular skin lesions. Histopathological examination revealed diffuse infiltrations of lymphocytes in the epidermis and dermis, with a CD3-positive immunophenotypic profile. Based on the clinical and histopathological examination, CETL was diagnosed. Both dogs were treated with isotretinoin in combination with IFN-α and showed clinical improvement with complete or partial remission. The disease in these dogs was well-controlled for more than 264 days of overall median survival time without any additional clinical signs after initiation of the treatment. In both the cases, the dogs were followed up for 27 months, and 10 months without any evidence of recurrence or metastasis, respectively.ConclusionsWe describe the clinical efficacy of isotretinoin combined with IFN-α in 2 dogs with CETL. Long-term management with isotretinoin combined with IFN-α was effective in treating CETL in these cases.

T cell-lymphoma in the eyelid of a 9-year-old English Setter

BackgroundEyelid tumours are frequently found in dogs, most of these being benign. In case of an ulcerating eyelid tumour, malignancy must be considered. We report a unique case of a low-grade peripheral T-cell lymphoma in the eyelid of a 9-year-old English Setter.Case presentationA 9-year-old Setter presented with a 6-month history of an eyelid ulcer. A malignant eyelid neoplasm was suspected, and the lesion was surgically excised. No other treatment was applied, and 19 months after excision the dog was still well. Histopathology revealed a diffuse lymphocytic infiltrate in the eyelid skin. Ulceration of the epithelium was seen, and the underlying tumour was composed of round and poorly demarcated pleomorphic tumour cells. The cytoplasm was pale and the nuclei heterogeneous. Numerous mitoses were present. The tumour cells stained strongly for CD3. The final diagnosis was a peripheral T-cell lymphoma not otherwise specified (NOS).ConclusionsThis is the first described case of a solitary T-cell lymphoma NOS in the haired eyelid skin in a dog. Lymphoma should be considered in case of a persistent eyelid ulcer and a biopsy should be performed. T-cell lymphoma is generally an aggressive disease; however, indolent cases are well known, and as this case shows, complete excision of a solitary T-cell lymphoma can be curable. Canine cutaneous epitheliotropic T-cell lymphoma is an important differential diagnosis, which must be recognized as the prognosis is very poor and systemic treatment is mandatory. The sub-classification of canine lymphoma is not complete, and further studies are needed to identify lymphoma subgroups and provide treatment guidelines.

Prevalence of CD20+ cutaneous epitheliotropic T-cell lymphoma in dogs: a retrospective analysis of 24 cases (2011-2018) in the USA.

Limited information is known about the baseline frequency of canine CD20 positive (+ ) cutaneous epitheliotropic T-cell lymphoma. A single canine case report has been published. To characterize the baseline frequency of CD20+ staining in cases of canine cutaneous epitheliotropic T-cell lymphoma; to assess its values as a prognostic indicator. Skin biopsies from 24 client-owned animals diagnosed with cutaneous epitheliotropic lymphoma were assessed. A retrospective review of medical records from 2011 to 2018. Clinical histories and previous histological and immunohistochemical slides were collected from 24 dogs and additional immunohistochemical staining was performed as needed to assess cases of cutaneous epitheliotropic T-cell lymphoma for CD3, CD20, CD79a and PAX5 staining characteristics. Staining characteristics were assessed for their statistical relationship to median survival time. Overall median survival time was 189days following the onset of clinical signs and 99days following definitive diagnosis; 54% of cases had CD20+ staining. There was no statistically significant correlation between staining characteristics and median survival time from onset of signs (P=0.54) or from diagnosis (P=0.61). Canine cutaneous epitheliotropic lymphoma has a higher instance of CD20 positivity than documented previously. This indicates that CD20 staining may be unsuitable to differentiate T-cell and B-cell cutaneous epitheliotropic lymphoma. This also may have therapeutic implications with the advent of canine CD20 monoclonal antibody therapies.

Phenotypic analysis of mice xenografted with canine epitheliotropic cutaneous T-cell lymphoma cells.

In canine epitheliotropic cutaneous T-cell lymphoma (ECTCL), neoplastic cells cause skin lesions and potentially metastasize to lymph nodes, blood and other organs. Murine models are potentially valuable for elucidating the molecular mechanisms responsible for regulation of ECTCL cell migration. To describe a phenotype of mice xenografted with canine ECTCL cells (EO-1 cells). Four NOD.CB17-Prkdcscid /J (NOD SCID) mice were used. EO-1 cells were subcutaneously xenografted into NOD SCID mice. After four weeks, the development of tumour lesions in skin and other organs was investigated. Mice developed skin lesions with metastasis to the lymph nodes, spleen, lung, blood and liver. Mice xenografted with EO-1 cells may be useful for studying the pathogenesis of canine ECTCL.

Is CCNU (lomustine) valuable for treatment of cutaneous epitheliotropic lymphoma in dogs? A critically appraised topic.

BackgroundCCNU and other treatment protocols are commonly offered to owners for the treatment of dogs diagnosed with cutaneous (epitheliotropic) T-cell lymphoma (CTCL). Chemotherapy protocols provide variable benefits; they have different side-effects, and they typically require monitoring to detect drug toxicity at a non-negligible cost to the owner. At this time, even though CCNU is most often recommended to treat dogs with CTCL, there is no clear consensus on the benefit of this drug. Knowing which chemotherapy protocol yields the highest rate of complete remission and longest survival times would help veterinarians and pet owners select treatment options based on the best evidence available. Our objective was to review the literature to compare the complete remission rates and survival times of CCNU-based protocols to those of other interventions. We critically assessed the data included in articles reporting treatment outcome in at least five dogs with CTCL. Single case reports and case series with less than five patients were not reviewed to avoid anecdotal evidence of lower quality.ResultsThe search for, and review and analysis of, the best evidence available as of February 8, 2017, suggests that CCNU and pegylated liposomal doxorubicin appear to yield the highest rate of complete remission in approximately one-third of dogs with CTCL. Other treatment protocols did not report usable information on remission rates. Without any treatment, the mean/median survival time in dogs with CTCL varied between 3 and 5 months. With CCNU protocols, the median survival time was 6 months and the one with retinoids (isotretinoin and/or etretinate), PEG L-asparaginase or prednisolone monotherapy was 11, 9 and 4 months, respectively; all these durations were obtained from small numbers of dogs, however.ConclusionsCCNU leads to a complete remission of signs in approximately one-third of dogs with CTCL, but such remissions are of short duration. The median survival time after CCNU appears longer than that without treatment, but other drugs appear to provide a better long-term prognosis. Further studies are required to investigate the effect of CCNU, alone or in combination, on remission rates, survival times and impact on quality of life.

Epitheliotropic cutaneous T-cell lymphoma associated with melanoma in a dog: case report

Several types of tumors affect dogs' skin. Simultaneously occurring neoplasms with different histological patterns might be rarely present in the same animal. This paper describes the occurrence of epitheliotropic cutaneous T-cell lymphoma and melanoma in a dog. The animal had nodular lesions in the abdominal region and serpiginous plaques on the dorsal region of the trunk. Cytology evidenced malignant fusiform cells from the abdominal lesions as well as few round cells from the dorsal. The histopathological examination of the abdominal lesions showed dermis with polygonal to spindle-shaped neoplastic cells. The lesion of the dorsal region evidenced neoplastic round cells with generally distinct cell borders and a moderate amount of eosinophilic cytoplasm. Abdominal lesions were positive for Melan A. Dorsal and forelimb lesions were positive for CD3. This study reports the occurrence of epitheliotropic cutaneous T-cell lymphoma and malignant melanoma in a crossbred Boxer dog and discusses the importance of performing immunohistochemical profile to confirm the phenotype of the tumor.

Cutaneous epitheliotropic lymphoma with dual CD3 and c‐kit expression in a dog

An 11-year-old 8.9-kg spayed female Boston Terrier was presented for evaluation of a mucocutaneous tumor on the right side of the upper lip that had been biopsied (punch biopsy) by the referring veterinarian. The histologic diagnosis was poorly differentiated round cell tumor involving the submucosa with patchy involvement of the mucosa. On presentation of the dog to Louisiana State University, the tumor was found to involve the mucosa and haired skin surface of the right upper lip. A fine-needle aspirate of the right mandibular lymph node contained atypical poorly differentiated round cells similar to those in the histologic sections. To further characterize the tumor, immunohistochemical analysis of the tumor on the lip was performed; tumor cells were strongly immunoreactive for both CD3 and c-kit in a cytoplasmic to membranous pattern, with CD3 expression having a more intense membranous component. The diagnosis was cutaneous epitheliotropic T-cell lymphoma with co-expression of CD3 and c-kit by neoplastic lymphocytes, an unusual finding. As receptor tyrosine kinases can be attractive targets for cancer treatment, expression of these molecular targets in tumors is a promising subject of future research.

Cyclooxygenase‐2 is not expressed by canine cutaneous epitheliotropic T‐cell lymphoma

Cyclooxygenase‐2 is not expressed by canine cutaneous epitheliotropic T‐cell lymphoma

Immunohistochemical profile of multicentric cutaneous epitheliotropic T-cell lymphoma with generalised lymphadenopathy in a Holstein-Friesian cow: a case report

Cutaneous epitheliotropic T-cell lymphoma with progression to superficial and internal lymph nodes and the spleen was diagnosed in a two-year-old Holstein-Friesian cow. The skin lesions included multiple hypotrichous to alopecic nodules, often with ulceration, which first appeared three months after calving and progressed quickly to cover the entire body. The cow was euthanized one month later. The ELISA test excluded bovine leukaemia virus infection. Histologically in the epidermis, the formation of Pautrier’s microabscesses and in the dermis, dense neoplastic infiltration with mild folliculotropism was observed. Similar neoplastic cells were present in the histological sections of lymph nodes and spleen. Immunohistochemical analysis was performed using CD3, CD79αcy, HLA-DR, WC1-N3 and Ki67 antibodies. Immunophenotyping results (CD79αcy–, CD3+, WC1-N3–) confirmed the αβ T-cell origin of neoplastic cells. The mean Ki67 index among neoplastic cells was 15.3%. On the basis of the immunohistochemical and histopathological results, the first case in Poland of cutaneous epitheliotropic T-cell lymphoma in a cow was confirmed. Additionally, MHC class II expression on approximately 10.4% of lymphoma cells was associated with a poor clinical prognosis. However, the up-regulation of MHC class II expression on accompanying cells suggested tumour immune surveillance, an antigen-specific immune response or immunosuppression. However, further investigations are needed to confirm these suspicions.