Malignant Transformation of T-cell Large Granular Lymphocyte Leukemia in a Dog

Abstract

ABSTRACT. An 8-year-old spayed female Golden Retriever was referred to us for evaluation of mild lymphocytosis. The peripheral lymphocytes were comprised of mostly large granular lymphocytes (LGLs), and flow cytometry showed that they were mostly CD3+8+ T lymphocytes. Clonal rearrangement of the T-cell receptor gene was identified in the peripheral blood, and the dog was therefore diagnosed with LGL chronic leukemia. The dog was subclinical without treatment until hospitalization on day 154, at which point the lymphocytes looked like lymphoblasts and the surface markers changed to CD3-8-. This was regarded as malignant transformation from LGL chronic leukemia to the acute type. Sequential chemotherapy was started, but the dog died on day 190. Necropsy revealed tumor cell infiltration into the heart, skin, and brain. KEY WORDS: flow cytometry, large granular lymphocyte leukemia, malignant transformation.

Composite lymphoma of concurrent T zone lymphoma and large cell B cell lymphoma in a dog

“…In the case reported here, this diagnosis was based on the dissimilar cytomorphological and immunophenotypic features of the tumors as well as the two distinct clonal signatures determined by NGS-based clonality testing. Transformation of indolent hematologic neoplasms into more aggressive forms, such as chronic lymphocytic leukemia into high-grade lymphoma, has previously been reported, and appears to occur occasionally in dogs [14–16]. However, in this case, the combined evidence of multiple testing modalities strongly suggests the concurrence of two distinct lymphomas rather than evolution of an indolent lymphoma into a more aggressive variant.…”

Acute undifferentiated leukaemia in a dog

“…9 In the present case, the entire myocardium was infiltrated by blast cells, being more severe within the ventricles, as shown on transthoracic echocardiography and at necropsy. To our knowledge, this finding has been described in chronic haematopoietic neoplasia (lymphoma and chronic leukaemia), [10][11][12] but not in AL. Similarly, diffuse and severe heart infiltration is rarely reported in human AL and when present, it is mostly of lymphoid lineage 13,14 and can induce acute cardiac failure or sudden death.…”

Malignant mesenchymoma with widespread metastasis including bone marrow involvement in a dog

“…A few case reports describing malignant transformation in dogs exist, such as benign bone disease developing into a malignant process (osteosarcoma or chondrosarcoma) [11][12][13][14] , and chronic leukemia transforming into an acute form of leukemia. 15 One of the more commonly reported cases of malignant transformation occurs in dogs infested with Spirocerca lupi, a nematode that induces the formation of an esophageal nodule that can transform into a malignant sarcoma. 16,17 Malignant transformation of a lipoma to liposarcoma has not previously been reported in dogs, and there have only been isolated reports in people.…”

“…Malignant transformation is a rare occurrence in both people and dogs. A few case reports describing malignant transformation in dogs exist, such as benign bone disease developing into a malignant process (osteosarcoma or chondrosarcoma), and chronic leukemia transforming into an acute form of leukemia . One of the more commonly reported cases of malignant transformation occurs in dogs infested with Spirocerca lupi , a nematode that induces the formation of an esophageal nodule that can transform into a malignant sarcoma .…”