Squash-preparation cytology from nasopharyngeal masses in the cat: cytological results and histological correlations in 30 cases

Upper airway obstruction in cats can be a life-threatening condition. Early recognition of clinical signs and an appropriate diagnostic approach increases the possibility of appropriate therapeutic choices. The purpose of this study was to assess the efficacy and diagnostic value of squash-preparation cytology in providing an accurate diagnosis of masses growing in the nasopharynx of cats. Cytological specimens prepared by a squash technique from nasopharyngeal masses in 30 cats were collected under direct endoscopic guidance and classified into four groups: benign inflammatory/hyperplastic mass, lymphoma, carcinoma and sarcoma. The cytopathological diagnosis was compared with the final histopathological diagnosis and indices of diagnostic test accuracy were calculated. The results showed good agreement between the cytological and histological diagnosis with a sensitivity of 0.94, a specificity of 0.81, a positive likelihood ratio of 0.9, a negative likelihood ratio of 0.9 and an overall accuracy of 0.9. Squash-preparation cytology is considered an accurate diagnostic tool for distinguishing benign from malignant nasopharyngeal masses in cats. For differentiation of lymphoma and lymphoid reactions histopathological confirmation is recommended.     

Nodal, uterine and meningeal gamma(delta) T-cell lymphomas in cattle

Three cases of bovine gamma(delta) T-cell lymphoma without skin involvement are described. Case 1 was a 17-month-old Holstein heifer with generalized lymphadenopathy. Case 2 was a 4-year-old Holstein cow that had multiple tumour masses in the uterine body and horns. Case 3, a 23-month-old Holstein bull was presented with generalized tremor, nystagmus and hyperesthaesia, and there were several tumour masses in the meninges. Cases 1 and 2 had epitheliotropic neoplastic infiltrates in the tonsillar epithelium and endometrial glands, respectively. Immunohistochemistry showed CD3+, WC1+, CD79a- lymphoma cells in all cases, and perforin was positive in two cases. Electron-dense granules were present in many neoplastic cells of all cases. These findings supported the cytotoxic gamma(delta) T-cell origin of the present lymphomas. Bovine gamma(delta) T-cell lymphoma may originate in a wide variety of anatomical sites and may be classified into several histological subtypes.     

Cutaneous epitheliotropic T‐cell lymphoma with dissemination to the liver in an eastern chipmunk (Tamias striatus)

Cutaneous epitheliotropic T‐cell lymphoma with liver metastasis was diagnosed in a 10‐year‐old eastern chipmunk (Tamias striatus). Physical findings included intracutaneous swellings, ulcerated plaques and nodules, hypotrichosis and erythema of the skin. Fine needle aspiration from the skin lesions showed a population of large lymphocytes and lymphoblasts, and was helpful in establishing the diagnosis antemortem. The post‐mortem examination revealed epitheliotropic lymphoma with liver metastasis. Immunohistochemistry proved the T‐cell origin both in the liver and skin tumours. Electron microscopy did not reveal any viral particles within the tumour. To the authors’ knowledge, this is the first case of lymphoma described in this species.     

Biphenotypic B‐cell lymphoma in 2 cats

The clinical and pathologic features of biphenotypic B‐cell lymphoma in 2 cats are reported. Clinical presentation varied from multiple cutaneous masses identified on the thigh in one cat to signs of lethargy from acute hemorrhage due to neoplastic infiltration of one kidney in the other. Cytology and histopathology confirmed round cell neoplasia in both cats and immunochemical staining demonstrated expression of both B‐ and T‐lymphocyte markers by the neoplastic cells in both animals. In PCR analysis of antigen receptor gene rearrangement, clonal rearrangement of B‐cell receptor genes and polyclonal T‐cell receptor gene rearrangement were demonstrated in both lymphomas. These findings were consistent with a diagnosis of B‐cell lymphoma with aberrant CD3 expression in both cases. Clinical progression of disease post diagnosis was rapid in both cats, suggesting a poor prognosis for this lymphoma type. Although bigenotypic receptor rearrangement of lymphoma cells appears relatively common, this is the first known report of actual biphenotypic lymphoma in cats.     

Cutaneous T cell lymphoma mimicking cutaneous histiocytosis: differentiation by flow cytometry

A two-year-old, neutered female cross-bred labrador had multiple cutaneous nodules, biopsies of which revealed pathological changes consistent with cutaneous histiocytosis. During a period of one month the dog developed multicentric lymphadenopathy, a retrobulbar mass and masses within the quadriceps and cervical muscles. Fine needle aspiration cytology of the cutaneous nodules and lymph nodes and histological examination of the cutaneous nodules and muscle masses suggested the presence of lymphoblastic lymphoma. A definitive diagnosis of CD8+ T cell lymphoma was achieved by immunophenotyping the tumour cells by flow cytometry.     

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.     

Diagnosis of mediastinal masses in dogs by flow cytometry

BACKGROUND: Biopsy of mediastinal masses can be invasive, but the procedure may be necessary if cytology of a mass aspirate is inconclusive. The 2 most common mediastinal masses, lymphoma and thymoma, may both be comprised of small lymphocytes. We investigated the ability of flow cytometry to distinguish between these 2 neoplasms. HYPOTHESIS: Flow cytometry of mediastinal mass aspirates may provide a definitive diagnosis of thymoma or lymphoma, reducing the need for biopsy. ANIMALS: Dogs with mediastinal masses presenting to the Veterinary Teaching Hospital/Animal Cancer Center were included in the study. METHODS: Aspirates obtained over 2 years that met the inclusion criteria (i.e. sufficient viable cells and a definitive diagnosis by means other than flow cytometry) were analyzed by flow cytometry to determine the percentage of cells expressing B- and T-cell markers, and co-expressing CD4 and CD8. RESULTS: All cases of thymoma (n = 6) consisted of > or = 10% lymphocytes coexpressing CD4 and CD8, a phenotype that is characteristic of thymocytes, whereas 6 of 7 lymphomas contained <2% CD4+CD8+ lymphocytes. The CD4+CD8+ lymphoma could be readily distinguished flow cytometrically from thymoma by light scatter properties. The phenotypes of the remaining lymphomas were CD4+ T cell (4), CD34+ (1) and B cell (1). CONCLUSIONS: Our studies demonstrate that flow cytometry is a useful tool for discriminating mediastinal masses. Lymphocyte-rich mediastinal masses could be unambiguously identified by flow cytometry in 13/13 cases.     

Multiple trichoepitheliomas in an alpaca (Lama pacos).

A 13-yr-old male Alpaca (Lama pacos) presented with multiple ovoid, well-circumscribed, nonulcerated intradermal masses. Individual masses measured 1-4 cm in diameter, and the overlying skin was alopecic. Several of the masses were surgically removed and evaluated microscopically. Histopathologic evaluation demonstrated multiple dermal cysts lined by neoplastic follicular epithelium. The cysts were filled with multiple layers of lamellar keratin and lined by abortive inner and outer root sheaths exhibiting cellular atypia, supporting the diagnosis of trichoepitheliomas. No additional treatment was initiated, and the alpaca continues to do well.     

Epitheliotropic cutaneous lymphoma (mycosis fungoides) in a coati

The aim of this report was to present a case of epitheliotropic cutaneous lymphoma (mycosis fungoides) in a coati. The animal was presented for evaluation of a non-pruritic nodule. Although the diagnosis of cutaneous histiocytoma was made histologically, plaques and erosions appeared in new areas of the skin along with rapid deterioration of body condition that led to euthanasia in less than one month following initial presentation. Epitheliotropic cutaneous lymphoma was confirmed with plaque biopsies. Cross-reactivity of a polyclonal antihuman CD3 antibody to coati T lymphocytes was also observed. Apart from skin lesions, only pleuritis was post-mortem diagnosed most likely because of immunosuppression secondarily to malignant neoplasia.     

Cutaneous presentation of canine intravascular lymphoma (malignant angioendotheliomatosis)

A 9-year-old female spayed Boxer dog presented with variably sized, firm, black, raised, exudative subcutaneous masses on her head, neck and trunk, that tended to fluctuate in size and frequently ulcerate. Skin biopsy showed that the dermis was expanded by a densely cellular mass of proliferative capillaries distended with large pleomorphic neoplastic round cells mixed with fibrin and erythrocytes. Intravascular lymphoma was diagnosed and immunostains were compatible with a CD8⁺ T lymphocyte histogenesis (CD3⁺/CD79a⁻/TCRαβ⁺/CD8α⁺). Post-mortem examination, four months after diagnosis, revealed neoplastic T-cells within meningeal arteries. We are unaware of other reports of a cutaneous presentation and ante-mortem diagnosis of intravascular lymphoma in the dog. Additionally, this vasoproliferative form of intravascular lymphoma has not been previously described in dogs.     

Bovine leukemia virus infection in a juvenile alpaca with multicentric lymphoma

A 13-month-old alpaca (Vicugna pacos) was presented for mandibular masses and weight loss. Histopathology of biopsy tissue was consistent with lymphoma. The alpaca was euthanized and necropsy revealed lymphoma masses in multiple organs. Immunohistochemistry for T- and B-cell typing was inconclusive. Serology and in-situ polymerase chain reaction hybridization were positive for bovine leukemia virus.     

Lymphoma in a rabbit: histopathological and immunohistochemical findings

Lymphoma is a very common lymphoid neoplasm in domestic animals, but few naturally occurring cases have been reported in rabbits. It presents at different sites within rabbits and, although the macroscopic pattern tends to be similar, different cell populations may be involved. This report describes a case of spontaneous lymphoma ocurring in a two-and-a-half-year-old pet Dutch dwarf rabbit. T and B lymphocyte infiltrates were observed in skin, lung, kidney, liver, intestine and lymph nodes, in each case affecting one or more tissue structures. The diagnosis, based on microscopic and immunocytochemical findings, was multicentric, T cell-rich B cell lymphoma with skin involvement.     

Precursor B-1 B cell lymphoma in a newborn calf.

A newborn Holstein female calf had neoplastic lesions in the skin and within the thoracic and abdominal cavities but not in the bone marrow, spleen, thymus, or most lymph nodes. Because the tumor cells were positive for CD79a (B cell marker), CD5 (B-1 cell marker) and terminal deoxynucleotidyl transferase (marker for immature lymphoid precursors), a diagnosis of precursor B-1 B cell lymphoma was made. The diagnosis was strongly supported by the fact that B-1 cells can develop in the fetus, unlike B-2 cells, which are produced after birth. The lymphoma was distinct from the typical calf form of lymphoma of B-2 cell origin, which does not express CD5 and is characterized by generalized lymphadenopathy and involvement of the bone marrow, blood and spleen.     

Cytologic variants of γδ T cell lymphoma in cattle

Two cytologic variants of γδ T cell lymphoma are described. Case 1 represented a giant cell variant found in a 5-year-old Holstein cow, which had large tumor masses in the pelvic cavity. This variant consisted of very large lymphoid cells with round to oval nuclei, medium-sized nucleoli and abundant cytoplasm. Case 2 was an aborted 7-month-old female Holstein fetus, which represented an immature cell variant. Most of the neoplastic lesions were located in the skin and pleural and peritoneal submesothelial tissues. The neoplastic tissues were composed of homogeneous growth of lymphoma cells characterized by inconspicuous nucleoli and finely dispersed chromatin. Both cases demonstrated CD3, CD8 and WC1 immunoreactivity. The current study revealed that there are 4 cytologic variants (common, giant cell, hypergranular and immature cell) in bovine γδ T cell lymphomas.     

Systemic amyloidosis in a mare

A mare with chronic cachexia had multiple skin nodules, abdominal masses (attached and free floating), and large lymph nodes. Fine-needle aspiration cytologic evaluation of a skin mass revealed multinucleated giant cells surrounding eosinophilic material. Histologic evaluation revealed extensive amyloid deposits within the masses, lymph nodes, and the interstitium of many organs. The presence of systemic (visceral) and organ-limited (cutaneous) forms of amyloid is rare in horses. Amyloid congophilia was retained after potassium permanganate oxidation. The fibrils were thus distinct from the AA (secondary) fibrils that are found in most cases of equine amyloidosis, suggesting that this mare may have had primary amyloidosis. Regardless of fibril type, the presence of multinucleated giant cells in association with eosinophilic material in cytologic preparations of skin nodules may suggest a differential diagnosis of amyloidosis in horses.     

RADIOGRAPHIC APPEARANCE OF CONFIRMED PULMONARY LYMPHOMA IN CATS AND DOGS

Herein we describe the thoracic radiographic appearance of confirmed pulmonary lymphoma. Patients with thoracic radiographs and cytologically or histologically confirmed pulmonary lymphoma were sought by contacting American College of Veterinary Radiology members. Seven cats and 16 dogs met the inclusion criteria, ranging in age from 4 to 15 years. Method of diagnosis was via ultrasound‐guided cytology (four), surgical biopsy (two), ultrasound‐guided biopsy (one), and necropsy (16). Radiographic findings varied but ranged from normal (one) to alveolar (six) and/or unstructured interstitial infiltrates (11), nodules and/or masses (eight), and bronchial infiltrates (four). Additional thoracic radiographic findings included pleural effusion and lymphadenopathy. The results of this evaluation indicate a wide variability in thoracic radiographic abnormalities in cats and dogs with pulmonary lymphoma.     

Canine cutaneous epitheliotropic T-cell lymphoma with vesiculobullous lesions resembling human bullous mycosis fungoides

The broad spectrum of clinical signs in canine cutaneous epitheliotropic T-cell lymphoma mimics many inflammatory skin diseases and is a diagnostic challenge. A 13-year-old-male castrated golden retriever crossbred dog presented with multifocal flaccid bullae evolving into deep erosions. A shearing force applied to the skin at the periphery of the erosions caused the epidermis to further slide off the dermis suggesting intraepidermal or subepidermal separation. Systemic signs consisted of profound weight loss and marked respiratory distress. Histologically, the superficial and deep dermis were infiltrated by large, CD3-positive neoplastic lymphocytes and mild epitheliotropism involved the deep epidermis, hair follicle walls and epitrichial sweat glands. There was partial loss of the stratum basale. Bullous lesions consisted of large dermoepidermal and intraepidermal clefts that contained loose accumulations of neutrophils mixed with fewer neoplastic cells in proteinaceous fluid. The lifted epidermis was often devitalized and bordered by hydropic degeneration and partial epidermal collapse. Similar neoplastic lymphocytes formed small masses in the lungs associated with broncho-invasion. Clonal rearrangement analysis of antigen receptor genes in samples from skin and lung lesions using primers specific for canine T-cell receptor gamma (TCRγ) produced a single-sized amplicon of identical sequence, indicating that both lesions resulted from the expansion of the same neoplastic T-cell population. Macroscopic vesiculobullous lesions with devitalization of the lesional epidermis should be included in the broad spectrum of clinical signs presented by canine cutaneous epitheliotropic T-cell lymphoma.     

IMAGING DIAGNOSIS—DORSAL MEDIASTINAL T‐CELL LYMPHOMA IN AN ALPACA

A 14‐year‐old male alpaca had refractory pleural effusion. The cause of the effusion was not apparent either radiographically or sonographically, or following a pleural fluid cytologic examination. Using computed tomographic (CT) examination, a dorsal paravertebral mass was identified and similar masses were found in the cranial mediastinum, retroperitoneal space, and adjacent to the hepatic entry of the portal vein. The histopathologic diagnosis was multicentric T‐cell lymphoma. CT examination may prove to be a valuable imaging modality in the localization and staging of neoplasia in new world camelids.     

Lymphoma with cutaneous involvement in three domestic rabbits (Oryctolagus cuniculus)

Three domestic rabbits ( Oryctolagus cuniculus ) with cutaneous lymphoma are described. Two rabbits were young (7 weeks and 1 years) and were euthanized within 1 week of showing clinical signs. Lymphoma was found in the skin and internal organs. The third rabbit was 9.5 years of age, and lived for more than 1 year after diagnosis. No response was seen to either 2 months of alpha-interferon administration or a 2.5-week course of isotretinoin treatment. After 1 year the rabbit died suddenly; the owner refused necropsy. Immunologic stains of the tumour in all three rabbits showed T cells to be the lymphoma cell type.