Gamma delta T‐cell large granular lymphocyte lymphoma in a dog

Abstract

A 2-year and 6-month-old female neutered Labrador Retriever with Horner syndrome, megaesophagus, and a mediastinal mass was referred to the Queen Mother Hospital for Animals of the Royal Veterinary College. A large granular lymphocyte (LGL) lymphoma was diagnosed on cytology; flow cytometric analysis revealed a γδ T-cell phenotype (CD3+, CD5+, CD45+, TCRγδ+, CD4-, CD8-, CD34-, CD21-). Chemotherapy was started with a combination of lomustine, vincristine, procarbazine, and prednisolone, followed by bleyomicin. Euthanasia was elected by the owners, due to progressive deterioration and lack of quality of life, 28 days after diagnosis. This is the first cytologic and immunophenotypic characterization of a canine γδ T-cell lymphoma with LGL morphology and probably of mediastinal origin. The role of chemotherapy in delaying the disease progression remains unknown.

Clinical response to a lomustine/cytarabine-based chemotherapy protocol in a case of canine large granular lymphocyte T-cell lymphoma with spinal involvement

“…Cytology is considered a reliable method of diagnosing lymphoma and PARR has been shown to have an agreement with flow cytometry and immunohistochemistry of 97% for B-cell and 93% for T-cell lymphomas in dogs (Lana et al, 2006). Unfortunately, the sample collected in our case had insufficient cellularity to perform a flow cytometric analysis, although its validity has been described in a previous case report of LGL lymphoma (Ortiz et al, 2015). A repeat MRI was not performed to confirm remission status and therefore the response assessment was purely clinical and based on the neurological examination at the time of each follow-up revisit.…”

“…Discussion This case report describes response to chemotherapy in a case of LGL lymphoma with spinal involvement and infiltration of the right lumbar aortic lymph node and the spleen, where the dog initially presented with paraplegia. To the author's knowledge, this is the first report of a LGL lymphoma with spinal involvement, although reports of lymphomas of similar morphology but with a different anatomical location exist in domestic dogs (Snead, 2007;Ortiz et al, 2015). When comparing response to treatment and survival to similar cases, our patient became ambulatory without support soon after starting chemotherapy and the overall survival of 195 days was longer than previously reported in a dog treated with lomustine and RT (Ueno et al, 2014) and another dog that received a lomustinebased combination protocol (Ortiz et al, 2015).…”

“…Cerebrospinal fluid (CSF) analysis may also provide a diagnosis by the identification of abnormal lymphocytes (Vandevelde and Spano, 1977). A variant of large granular lymphocyte (LGL) lymphoma has been described in dogs in different anatomical locations, including the intestinal tract (Snead, 2007) and presumably the mediastinum (Ortiz et al, 2015); in one case treated with a multidrug chemotherapy protocol, the dog survived 28 days and was ultimately euthanased due to progression of clinical signs (Ortiz et al, 2015). Treatment options for localised lymphoma include surgery, RT and chemotherapy alone or in combination.…”

A case of hemophagocytic syndrome progressing into large granular lymphoma in a dog

“…Furthermore, we diagnosed this animal with lymphoma that was undetected during the initial workup. LGL lymphoma is a subtype of T‐cell lymphoma characterized by lymphocytes that contain intracytoplasmic azurophilic granules . Canine T‐cell lymphoma with LGL morphologies are known as LGL lymphoma/leukemias and HS‐TCL in the canine WHO classification system .…”

Dogs with acute myeloid leukemia or lymphoid neoplasms (large cell lymphoma or acute lymphoblastic leukemia) may have indistinguishable mediastinal masses on radiographs

“…Additionally, some dogs with acute myeloid leukemia do not have many neoplastic cells in circulation or marked cytopenias, which are expected with an acute leukemia . Conversely, some dogs with lymphoma have large numbers of neoplastic lymphocytes in circulation and substantial bone marrow involvement, which mimics an acute leukemia of either myeloid or lymphoid origin . Therefore, it can be a diagnostic challenge to determine if a dog has acute myeloid leukemia or a lymphoid neoplasm (lymphoma or acute lymphocytic leukemia).…”