Myeloproliferative disease in a calf

Erythroblastic sarcoma in the thoracic cavity of a cow

Erythroblastic sarcoma in a 10-year-old Japanese Black cow with anemia is described. Tumor masses or nodules were located mainly in the thoracic cavity, and some lymph nodes were slightly enlarged. Although neoplastic involvement of the bone marrow was detected, the cow was not leukemic. The diagnosis was made based on the localized distribution of neoplastic lesions, no increase of intravascular nucleated cell number, deeply eosinophilic cytoplasm in some tumor cells, and frequent immunoreactivity of the tumor cells for hemoglobin. The tumor cells were characterized by marked pleomorphism and atypia; such morphological deviation from their normal counterparts may be connected with functional deviation resulting in the sarcomatous growth of these erythroid cells.

Aspectos epidemiológicos, clínicos, hematológicos e anatomopatológicos da leucemia eritroide aguda (LMA M6) em gatos

Os aspectos epidemiológicos, clínicos, hematológicos e anatomopatológicos da leucemia eritroide aguda (LMA M6) foram estudados em 10 gatos que morreram em consequência dessa condição. Os resultados obtidos diferem daqueles previamente descritos na literatura nos seguintes aspectos: 1) a doença ocorreu na forma de um modelo bimodal relacionado à idade dos gatos afetados, em que 50% tinham 1-3 anos de idade e 50% tinham 10 anos de idade ou mais; 2) quase todos os gatos afetados (87,5%) demonstravam policromasia, possivelmente decorrente de eritropoese extramedular; 3) em todos os casos havia múltiplos focos de células hematopoéticas, principalmente eritropoeticas, em múltiplos órgãos, que incluíam baço (85,7%), linfonodos (71,4%), fígado (57,1%) e rim (28,6%); 4) em alguns casos (28,6%) esses focos podiam ser vistos macroscopicamente, na forma de metástases, mas sempre diferiam histologicamente da medula óssea quanto à proporção dos precursores eritroides envolvidos; 5) em pelo menos um caso ocorreu um continuum patologicum até outra forma de LMA (LMA M4), um fenômeno denominado "infidelidade de linhagem". Esse artigo discute essas diferenças e reforça os critérios fundamentais para se estabelecer o diagnóstico definitivo dessa que é a forma mais importante de leucemia em gatos na nossa região.

Acute myeloid leukemia with mastocytic and megakaryocytic differentiation in a calf

A diagnosis of acute myeloid leukemia was made in a 10-month-old Holstein female calf. The leukemia was macroscopically characterized by great enlargement of the spleen and moderate enlargement of some lymph nodes. Histochemical and immunohistochemical examination disclosed the presence of neoplastic cells either containing metachromatic and tryptase-positive granules or expressing factor VIII-related antigen. The granules, which were positive for naphthol AS-D chloroacetate esterase and did not have particulate contents, were distinct from those of basophilic leukemia cells. This leukemia was thought to be derived from a common myeloid progenitor capable of giving rise to megakaryocyte-erythrocyte progenitors and granulocyte-monocyte progenitors with the ability to differentiate into mast cells.

Primary erythrocytosis in a Japanese black calf: a case report

An 8-month-old Japanese Black heifer with severe erythropoietic symptoms was subjected to clinical, histological and cytological examinations. During the 1 month clinical observation period, severe increases in RBC count, packed cell volume and haemoglobin concentration were observed. The plasma erythropoietin (Epo) concentration of the heifer (20.7 mIU/ml) was similar to that observed in normal control heifers. Blood gas examinations of the arterial and venous blood revealed low levels of partial pressure O(2) (PaO(2)), partial pressure CO(2) (PaCO(2)) and O(2) saturation (SaO(2)), while the blood pH was within the normal range. Gross lesions could not be detected. However, microscopic observation revealed severe proliferation of erythroblasts in the bone marrow and in the spleen without evidence of neoplastic changes. Based on these clinical and pathological examinations, we diagnosed the heifer as being the first case of primary erythrocytosis in Japanese Black cattle.

Myeloblastic leukemia with massive neoplastic infiltration of the skin and mediastinum in a cow

An acute myeloblastic leukemia was found in a 3.5-year-old Holstein cow. The neoplasm was characterized by massive tumor growths, and there were multiple tumor nodules in the dermis or subcutis and a large tumor mass in the mediastinum. This tumor showed negative reactivity for CD3, CD79a, major histocompatibility complex class II and myeloid/histiocyte antigen. Ultrastructural features such as dispersed cytoplasmic granules and poorly developed organelles were compatible with those of early promyelocytes.