Progression of an orbital T-cell rich B-cell lymphoma to a B-cell lymphoma in a dog

Tumours involving the retrobulbar space in cats: 37 cases

OBJECTIVES

The aim of this multicentre retrospective study was to describe the clinical presentation, imaging findings, diagnosis and outcomes of cats with retrobulbar neoplasia.

METHODS

A total of 37 cats that were diagnosed with retrobulbar neoplasia and underwent advanced imaging were recruited from searches of the clinical records of two referral hospitals. All cats had neoplasia confirmed via cytology or histopathology. Data relating to the signalment, presentation, results of investigations, treatment and outcome were recorded. A review of imaging studies was performed where possible.

RESULTS

In total, 23 cases (62%) were presented with respiratory signs. Exophthalmos was the most common ophthalmological examination finding, present in 18 cases (49%). Thirty-two cases (86%) had secondary extension of neoplasia to the retrobulbar space (most commonly from the nasal cavities), present in 20 cases (54%), of which 12 were lymphoma. In cases where contrast was administered, 28/35 (80%) had contrast-enhancing masses. Orbital extension was detected in 21 cases (57%), exophthalmos in 22 (59%), globe deformation in 12 (32%) and local lymphadenomegaly in 22 (61%). In total, 36 (97%) retrobulbar tumours were malignant. Thoracic imaging, where it was performed, was concerning for metastasis in 8/25 cases (31%), with abdominal imaging suggestive of metastasis in 5/12 (42%). The most common diagnosis was lymphoma with 19 cases (51%), with nasal lymphoma representing 12 of these, followed by carcinoma in 10 (27%). The median survival time, for cases where death was recorded, was 85 days (range 1-263 days).

CONCLUSIONS AND RELEVANCE

To the authors' knowledge, this is the largest study of neoplasia affecting the feline retrobulbar space. Retrobulbar tumours in cats are overwhelmingly malignant, and commonly due to secondary extension of tumours originating elsewhere. Lymphoma, particularly arising from the nasal cavities, was the most common cause. Cats presenting with signs suggestive of retrobulbar disease should be assessed for disease affecting any of the structures of the head.

Lymphoma in Psittacine Birds: A Histological and Immunohistochemical Assessment

In psittacine birds, round cell neoplasms that originate from lymphocytes, plasma cells, histiocytes, or mast cells are sporadic and poorly described. The lack of morphological and immunohistochemical diagnostic criteria or grading schemes make specific diagnoses and prognoses challenging. We assessed cases of psittacine birds diagnosed with round cell neoplasia from 3 North American veterinary diagnostic laboratories to describe the diagnostic features of these tumors. For all cases, demographic data, anatomic distribution, histological features, and immunoreactivity for T (CD3) and B (Pax5 and MUM-1) cell markers were assessed using tissue microarrays and whole slide mounts. Thirty-eight psittacine birds representing 14 species were included. Tumors were mainly infiltrative and multicentric, were composed of homogenous sheets of round to polygonal cells, and commonly presented with a high mitotic count (average 21 mitoses per high-power field). Based on Pax5 immunoreactivity, B-cell lymphoma was most common (19/38 [50%]), and was significantly associated with involvement of the gastrointestinal and urogenital systems. Of the 38 cases, 6 (16%) were consistent with T-cell lymphoma, 3 (8%) with plasma cell tumor, and 3 (8%) were double-reactive for both B- and T-lymphocyte markers. This is the first study to describe morphologic and immunohistochemical features of round cell neoplasia in a large number of psittacine birds, and provides benchmark data for future studies aimed at elucidating the diagnosis and prognosis of these neoplasms. These data also provide useful information about reactivity of commercially available antibodies as lymphocyte markers in tissues of multiple psittacine species.

Use of immune repertoire sequencing to resolve discordant microscopic and immunochemical findings in a case of T cell-rich large B cell lymphoma in a young dog

Background

Lymphocytic neoplasms with frequent reactive lymphocytes are uncommonly reported in dogs, and can pose a diagnostic challenge. Different diagnostic modalities such as cytology, flow cytometry, histopathology, immunohistochemistry, and clonality testing, are sometimes required for a diagnosis. This report illustrates the value of using a multi-modal diagnostic approach to decipher a complex lymphocytic tumor, and introduces immune repertoire sequencing as a diagnostic adjunct.

Case presentation

A 10-month-old Great Dane was referred for marked ascites. Cytologic analysis of abdominal fluid and hepatic aspirates revealed a mixed lymphocyte population including numerous large lymphocytes, yielding a diagnosis of lymphoma. Flow cytometrically, abdominal fluid lymphocytes were highly positive for CD4, CD5, CD18, CD45, and MHC II, consistent with T cell lymphoma. Due to a rapidly deteriorating clinical condition, the dog was euthanized. Post mortem histologic evaluation showed effacement of the liver by aggregates of B cells surrounded by T cells, suggestive of hepatic T cell-rich large B cell lymphoma. Immune repertoire sequencing confirmed the presence of clonal B cells in the liver but not the abdominal fluid, whereas reactive T cells with shared, polyclonal immune repertoires were found in both locations.

Conclusions

T cell-rich large B cell lymphoma is a rare neoplasm in dogs that may be challenging to diagnose and classify due to mixed lymphocyte populations. In this case, the results of histopathology, immunohistochemistry and immune repertoire sequencing were most consistent with a hepatic B cell neoplasm and reactive T cells exfoliating into the abdominal fluid. Immune repertoire sequencing was helpful in delineating neoplastic from reactive lymphocytes and characterizing repertoire overlap in both compartments. The potential pitfalls of equating atypical cytomorphology and monotypic marker expression in neoplasia are highlighted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02783-3.

Evaluation of cytology and histopathology for the diagnosis of canine orbital neoplasia: 112 cases (2004-2019) and review of the literature

OBJECTIVE

To provide an updated overview of canine orbital neoplasia, to compare diagnostic utility of cytology and histopathology, and to evaluate alternative sampling modalities, particularly image-guided core needle biopsy.

PROCEDURES

A medical records search was performed to identify dogs with orbital neoplasia. Data were collected regarding signalment, diagnosis, vision status, imaging modalities, and sample collection methods. A reference population with orbital neoplasia was also identified via literature search for comparison with regard to final diagnosis.

RESULTS

One hundred and twelve dogs met selection criteria. In the study and reference populations, respectively, diagnoses were grouped as follows: mesenchymal tumors 40% and 35%, epithelial tumors 35% and 18%, tumors of neural origin 8% and 37%, and round cell 17% and 10%. The most common diagnoses in the study group were nasal adenocarcinoma, osteosarcoma, lymphoma, and meningioma. Cytology results were available for 47 dogs and histopathology results were available for 95 dogs. Both cytology and histopathology results were available for 30 dogs, in 53% of which results were discordant. Cytology samples were nondiagnostic or provided a diagnosis that was later overturned in 32% of cases in which they were obtained. Results from core needle biopsy samples were nondiagnostic or overturned by surgical biopsy results in only 13% of cases. No significant complications were associated with any sampling method.

CONCLUSIONS

Orbital neoplasia is common in dogs. Histopathology is superior to cytology in providing a definitive diagnosis. Image-guided core needle biopsy appears to be a safe and effective means of obtaining samples.

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

BACKGROUND

Eyelid 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 PRESENTATION

A 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).

CONCLUSIONS

This 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.

Morphological characterization of canine retrobulbar lymphoma

This report characterized seven cases of canine retrobulbar lymphoma that have been diagnosed during 2008 to 2014 by immunophenotyping of CD3 and Pax5. Classification of lymphoma were performed according to the revised WHO guidelines. Four retrobulbar lymphomas were of T-cell origin, while the others were of B-cell. Out of 7 cases, four subtypes were diagnosed in this study; T-cell-rich large B-cell lymphoma (3/7), T-cell lymphoblastic lymphoma (2/7), peripheral T-cell lymphoma (1/7), and cutaneous nonepitheliotropic lymphoma (1/7). T-cell-rich large B-cell lymphoma was found to be the most frequent subtype found.

B-cell lymphoblastic lymphoma of the nictitating membrane as the first presenting sign in a 2-year-old Springer Spaniel

B-cell lymphoblastic lymphoma is an aggressive malignant disease. Necropsy and microscopical examination revealed widespread disease with a high proliferation index. This is the first reported case of B-cell lymphoblastic lymphoma presenting in the ocular region and only the second reported lymphoma of the nictitating membrane.

Indolent T-cell-rich small B-cell hepatic lymphoma in a Golden Retriever

An 11-year-old female spayed Golden Retriever presented for an incidentally found liver mass. The hepatic mass and intra-abdominal lymph nodes had a marked heterogeneous T-cell population and far fewer numbers of small clonal B cells. This T-cell-rich small B-cell lymphoma had a unique histological pattern and indolent clinical course.

Immunohistochemical Evaluation of Mononuclear Infiltrates in Canine Lupoid Onychodystrophy

Claw biopsy samples of 11 dogs with lupoid onychodystrophy were evaluated. They were stained with hematoxylin and eosin and with antibodies against CD 3 as a T-cell marker, BLA 36 and HM 57 (CD 79α) as B-cell markers, and lysozyme, Mac 387, and major histocompatibility complex (MHC) class II as a marker for histiocytes using an immunoperoxidase and avidin-biotin technique. Inflammatory cells were counted in five high-power fields. The inflammatory infiltrate comprised predominantly B cells and T cells. Macrophages were typically only present in small numbers. CD 3, BLA 36, lysozyme, and MHC class II preserved significant antigenicity during formalin fixation and short decalcification for 24–48 hours, whereas CD 79α and particularly Mac 387 seemed to be more susceptible to denaturation by the decalcification process.

A rare case of hepatic T-cell rich B-cell lymphoma (TCRBCL) in a juvenile dog

A 7-month-old castrated male French Bull dog was presented with vomiting, lethargy, anorexia and weight loss of 2 weeks duration. The patient’s history and clinical manifestations of suspected hepatopathy were subjected to ultrasonography, radiography, biochemical investigations and cytology of hepatic lesion. The cytologic impression was hepatic lymphoma, which was later confirmed by histopathology. The neoplastic cells were strongly diffusely immunoreactive for PAX5, but not immunoreactive for CD3, and B lymphocyte specific clonal proliferation was detected using by assay of antigen receptor rearrangement. Large numbers of immunoreactive mature non-neoplastic lymphocytes were admixed with the neoplastic cell population. Therefore, the immunohistochemical results were definitively consistent with a T-cell rich B-cell lymphoma (TCRBCL). This is the first description of a hepatic TCRBCL in a juvenile dog showing a poor response to aggressive chemotherapy.

Extra-nodal subcutaneous Hodgkin’s-like lymphoma and subsequent regression in a cat

Hodgkin’s-like lymphoma is a slow growing neoplasm, usually affecting the lymph nodes of the head and neck, which has been sporadically described in veterinary patients. This report describes the clinical and histopathological features in a 9-year-old male neutered Siamese cat that presented with a 6 week history of mid-dorsocranial swelling. Immunohistochemistry demonstrated positive staining for CD79a, paired box protein and B lymphocyte antigen-36, with variable, weak-to-moderate cytoplasmic staining for human leukocyte antigen-DR and CD18, and negative staining for antimacrophage antibody. The diagnosis based on incisional biopsy was Hodgkin’s-like lymphoma; however, no evidence of neoplasia was found following wide surgical excision. This case report demonstrates two unreported items of note: the novel extranodal site of Hodgkin’s-like lymphoma in a cat and tumour regression following initial biopsy. It is hypothesised that the surgical trauma of biopsying the lesion or the introduction of foreign material may have caused the regression of the neoplastic cells through induction of an anti-tumour immune or inflammatory response.

Supposed primary conjunctival lymphoma in a dog

A 7-year-old, male mixed-breed dog was presented for evaluation of a well-delineated, pink, oval and slightly firm mass with a smooth regular surface that was expanding approximately 60% of the lower eyelid conjunctiva and the lateral canthus. The dog had a supposed primary B-cell lymphoma at the temporal canthus of the upper eyelid conjunctiva of the same eye that had been removed approximately 3 years earlier. No metastases were detected at either presentation. Histologically, the conjunctival lamina propria was effaced by a well-delineated, unencapsulated and expansile highly cellular neoplasm composed of sheets of round cells that were immunohistochemically positive for CD20 and CD79a negative for CD3. Based on the microscopic and immunohistochemical findings, a diagnosis of supposed primary B cell conjunctival lymphoma was made. Primary ocular and adnexal ocular lymphomas in dogs are rarely reported and their behavior is poorly characterized. Further tumor recurrence was not observed one year post operatively. This case was considered unusual because of its conjunctival involvement and the clinical course with recurrence after three years of a surgical therapeutic procedure.

Uveodermatologic lymphoma in two young related Portuguese water dogs

PURPOSE

Canine lymphoma (CL) is one of the most common forms of spontaneous canine neoplasia. Improved understanding of the genetic and environmental factors associated with CL may provide benefits for the study of non-Hodgkin's and Hodgkin's lymphoma in humans. Uveodermatologic lymphoma is reported in a single household of Portuguese water dog, and the etiology is discussed.

METHODS

A 1-year-old female intact Portuguese water dog was referred to the Ophthalmology Service of the Veterinary Teaching Hospital of the Autonomous University of Barcelona because of acute blepharospasm of the right eye in association with a multinodular dermatosis. Physical and ophthalmological examination and a complete diagnostic work-up, including skin and ocular histopathology and immunohistochemistry, were performed. Three months prior, in Galicia (Spain), 1200 km away from Barcelona, a male dog of the same litter showed very similar oculodermatological clinical signs and skin histopathology, and immunohistochemistry were obtained.

RESULTS

The clinical diagnoses were anterior exudative uveitis, iridal masses, and secondary glaucoma. Histopathology and immunohistochemistry revealed a nonepitheliotropic lymphoma rich in B cell in dog 1 and rich in T cell in dog 2.

CONCLUSION

It is proposed that an underlying genetic predisposition could have played a role in the development of lymphoma in these two young related dogs.

Surgical management of orbital nodular granulomatous episcleritis in a dog

A 27 kg, 6-year-old, male castrated German shorthaired pointer presented to the University of Missouri, Veterinary Teaching Hospital with the complaint of progressive exophthalmia of 2 years duration optical density (OD). Lack of retropulsion OD was noted on physical examination. Anterior segment examination OU and fundic examination OS did not reveal any abnormalities. Examination of the fundus OD revealed focal scleral indentation of the inferior nasal globe. The indentation changed location with globe movement OD. MRI and CT scan revealed a well-circumscribed, approximately 2 cm in diameter mass located caudal and ventral to the affected globe that appeared to communicate with the nictitating membrane with absence of any bony involvement. A modified lateral orbitotomy was recommended and performed to remove the orbital mass and nictitating membrane en-bloc. Histopathology and immunohistochemistry of the mass confirmed a diagnosis of nodular granulomatous episcleritis (NGE). Postoperatively, the dog developed absolute keratoconjunctivitis sicca (KCS). Examples of primary episcleral inflammation in the dog include diffuse episcleritis, NGE, nodular fasciitis, fibrous histiocytoma, proliferative conjunctivitis/keratoconjunctivitis, pseudotumor, and Collie granuloma. The etiology of these episcleral inflammations is presumed to be immune mediated. To our knowledge, this is the first report of NGE affecting the orbital region of a dog. Development of absolute KCS resulting from excision of the nictitating membrane is also supported by this case.

Immunophenotypic and Histologic Classification of 50 Cases of Feline Gastrointestinal Lymphoma

The purpose of this study was to determine the immunophenotype and histologic classification of 50 cases of feline gastrointestinal lymphoma. Classification was determined using the National Cancer Institute Working Formulation and the Revised European and American Lymphoma/ World Health Organization classification system. Tissue sections were stained with HE, phosphotungstic acid hematoxylin, anti-CD3, anti-CD79a, and anti-BLA.36. Overall, B-cell tumors predominated at 54% (27/50), including 16 diffuse large with immunoblastic nuclear type, 2 diffuse large with centroblastic nuclear type, 3 small lymphocytic, 4 lymphocytic intermediate type, and 2 T-cell-rich large B-cell lymphomas. T-cell tumors comprised 38% (19/50), including 15 epitheliotropic small lymphocytic and 4 lymphoblastic. Three tumors (6%) were nonreactive for B- and T-cell markers and had eosinophilic cytoplasmic granules when stained with HE. Gastric tumors were diagnosed in 24% (12/50) of cats, and 18% (9/50) were present only in the stomach. All gastric lymphomas were of B-cell lineage. Small intestinal lymphoma predominated, with 74% (37/50) of cats affected: T-cell tumors comprised 52% (19/37); 38% (14/37) were B-cell tumors; 8% (3/37) were nonreactive for B- and T-cell markers; and 2% (1/37) expressed both CD3 and BLA.36. Of the 8 cats (16%) that had lymphoma of the large intestine, 88% (7/8) had B-cell tumors and 12% (1/8) had T-cell tumors. The strongest association between gastrointestinal lymphoma immunophenotype, histologic classification, and location occurred in the stomach, where there was a predominance of diffuse large B-cell lymphoma of immunoblastic nuclear type.

Histopathologic, Immunohistochemical, and Cytologic Analysis of Feline Myeloma-Related Disorders: Further Evidence for Primary Extramedullary Development in the Cat

Feline myeloma-related disorders (MRD) are rare neoplasms of plasma cells. The multistep transformation model of myeloma in humans is based on the premise that plasma cells undergo neoplastic transformation primarily within the intramedullary compartment and that over time they become poorly differentiated and metastasize to extramedullary locations. Historically, diagnostic criteria used for human multiple myeloma have been applied to the cat, with the assumption that feline MRD commonly arises in the intramedullary compartment. Our objectives were to describe the features of feline MRD confirmed by cytology, histopathology, histochemistry, and immunohistochemistry and to categorize these tumors. A priori hypotheses were 1) tumor category predicts survival and 2) cats with well-differentiated tumors commonly have extramedullary involvement in contrast to human myeloma patients. This multicenter, retrospective study identified 26 MRD cases. There was good agreement between histopathologic and cytologic tumor categorization. Histochemistry and immunohistochemistry were shown to be valuable adjunct tests in the diagnosis of MRD. Cats with well-differentiated tumors had increased median survival relative to those with poorly differentiated tumors (254 versus 14 days). We have reported that marked extramedullary involvement at initial clinical presentation is significantly more common in the cat than in human MRD patients. In this study, we demonstrate that cats with well-differentiated tumors more commonly have extramedullary involvement than human myeloma patients with well-differentiated tumors (90% versus 20%, P < 0.0002). These results contrast strongly with the human myeloma model of primary intramedullary neoplastic transformation and suggest that primary extramedullary neoplastic transformation may be more common in feline MRD.

Phagocytic plasmacytoma in a dog

A 4-year-old neutered male Golden Retriever was presented to the oncology service of the North Carolina State University Veterinary Teaching Hospital for staging of a histiocytic sarcoma of the left forelimb, diagnosed on the basis of biopsies submitted by the referring veterinarian. Cytologic assessment of aspirates of 2 splenic nodules identified on ultrasonographic examination of the abdomen revealed a highly phagocytic population of neoplastic round cells morphologically suggestive of plasma cells. Histologic assessment of the forelimb mass after amputation of the limb revealed a neoplastic round cell population demonstrating extensive cytophagia and erythrophagia. Immunohistochemical analysis of the tumor population revealed it to be negative for BLA.36 with sporadic positivity for lysozyme and CD79a. Immunofluorescent evaluation revealed weak tumor cell positivity for immunoglobulin (Ig) A and IgM, but extensive strong positivity for IgG, confirming the plasma cell origin of the tumor. Although extensive phagocytic activity may strongly suggest histiocytic origin, plasma cell origin must also be considered among the differential diagnoses for phagocytic round cell tumors.

Bilateral nodular lymphocytic conjunctivitis in a horse

A Russian jumper horse presented because of an ocular perilimbal conjunctival mass and, on clinical examination, two bilateral conjunctival masses were found, of different size and conformation. Attempts at complete excision of the left eye mass and excisional biopsy of the right eye mass were performed. The left eye mass recurred rapidly, but resolved completely after topical corticosteroid therapy. The two lesions had similar histopathologic features, characterized by focal, chronic, primarily lymphocytic conjunctivitis with follicular lymphoid hyperplasia. Special histopathologic staining techniques (Gomori methenamine silver and acid fast stains) and immunohistochemistry (for CD3, BLA36 and lysozyme) failed to reveal any etiologic agents and indicated an inflammatory lesion composed of a heterogeneous population of lymphocytes and macrophages (nodular lymphocytic conjunctivitis). The lesions were indistinguishable, clinically and behaviorally, from what has been reported as 'conjunctival pseudotumor' in the horse. Equine conjunctival pseudotumor/nodular lymphocytic conjunctivitis has been reported to be unilateral and have a good prognosis after partial or complete surgical excision. This is the first reported case of bilateral nodular lymphocytic conjunctivitis in a horse and for which surgical excision alone was not curative.

Unicentric extranodal lymphoma of the upper eyelid conjunctiva in a dog

A case of conjunctival lymphoma in a 4-year-old Siberian husky is reported. A large red mass protruding from the conjunctiva of the upper eyelid of the right eye was present. Irritation, blepharospasm and epiphora were revealed on initial ophthalmic examination. After anti-inflammatory treatment, surgery was performed. Histologically, the mass consisted of large polygonal cells with a high nucleus to cytoplasm ratio, moderate amounts of slightly eosinophilic cytoplasm, pleomorphic nuclei with vesicular chromatin and prominent multiple nucleoli. Mitotic figures were frequent. Approximately 70% of the neoplastic cells were CD3 positive and CD79alpha negative. On the basis of histologic and immunohistochemical findings, a diagnosis of intermediate-grade, diffuse large-cell lymphoma with T-cell immunophenotype was made. The surgical area healed uneventfully and, although chemotherapy was not received, after 12 months the dog exhibited no recurrence. To the authors' knowledge, this is the first report of unicentric extranodal conjunctival lymphoma in a dog.

Spontaneous T-cell-rich B-cell lymphoma in a cynomolgus monkey (Macaca fascicularis)

A spontaneous T-cell-rich B-cell lymphoma (TCRBCL) occurred as a subcutaneous mass in the buccal region and enlarged submandibular lymph node in a 6-year-old female cynomolgus monkey (Macaca fascicularis). The constituent cells were examined by histology, immunohistochemistry and the double labeled-immunofluorescence method (dl-IF). Further, in situ hybridization (ISH) was employed to detect the gene expression of Epstein Barr virus (EBV). Histologically, the mass was comprised mainly of neoplastic large lymphoid cells and reactive small mononuclear cells. Immunohistochemically, the neoplastic large lymphoid cells were positive for CD20, CD79 alpha, MHC class II, and either IgG, IgM, or IgA. Polyclonal Ig production by the neoplastic large lymphoid cells was demonstrated by dl-IF, although IgG-positive ones predominated in number. On the other hand, most of the small mononuclear cells were positive for CD3 and were regarded as reactive T lymphocytes, while the remaining cells appeared to be histocytes or reactive B-cells. Transcripts of EBV gene were not demonstrated in these neoplastic or reactive cells by ISH. This is the first reported case of spontaneous TCRBCL in the cynomolgus monkey.