Feline cardiac lymphoma: a case report

Paulo (SP), Brasil E-mail: henrique123magalhaes@yahoo.com.br Abstract Cancer is the main cause of death among pet animals. FeLV, the feline leukemia virus, increases the odds of domestic felines’ developing lymphoma or leukemia 62 fold. The cardiac lymphoma is a rare neoplasia and little is known about it in Veterinary Medicine. Therefore, it has been sought to report a case of cardiac lymphoma in a two-year-old, FeLV-positive feline patient, who presented dyspnea, lack of appetite, progressive loss of weight, and apathy. By means of supplementary examination, the presence of a mass attached to the heat would be verified, and lymphoma was diagnosed upon histopathological examination. It is thus concluded that this neoplasia was associated to the feline leukemia virus and that, in spite of the supplementary examinations’ having been utterly important for a correct diagnosis, the lack of an early definition aggravated the clinical picture of the patient and hindered


Introduction
Cancer is the main cause of death among pet animals and accounts for 32% of the fatalities in domestic felines (Withrow, 2007). Its diagnosis is becoming ever more commonplace in the veterinary clinical practice (Ferraz et al., 2008), partly tied to the ever greater longevity of the animals (Withrow, 2007).
Around 33% of all tumors in felines are hematopoietic, being most frequently found in domestic cats (Vonderhaar & Morrison, 1998). The prevalence for that species is superior by comparison to the other domestic species (Court et al., 1997;Gabor et al., 1998).
The malignant proliferation of the lymphocytic cells -originated mainly in lymphoid organs, such as lymph nodes, bone marrow, liver, and spleen -typifies lymphomas. Nevertheless, said development may take place in any other organ due to the ongoing migration of the lymphocytes to the various parts of the body (Daleck et al., 2008). In regard of the chest cavity lymphomas, they are more frequent in the thymus, although they may also be observed in the sternal lymph nodes and by the mediastinum (Holzworth, 1987).
Cardiac neoplasia is extremely rare in cats (Buchanan, 1992). A query in the Veterinary Medical Database, pertinent to the years between 1982 and 1993, revealed that, from a total of 210,388 cats examined, only 58 would present cardiac tumors (0.027%), lymphoma being the most common diagnosis (Tilley & Goodwin, 2002).
The feline leukemia virus (FeLV) performs directly in the tumor genesis, whilst increasing the odds of infected domestic felines' developing lymphoma or leukemia 62 fold when compared to non-infected animals (Hartmann, 2012). Though regarded as an oncogenic virus, the development of the neoplasias accounts for just about 10 to 25% of the fatalities linked to the disease (Sparkes & Papasouliotis, 2012).
In the heart, the lymphoma is a rarely; yet, little is known of its diagnosis, treatment, and prognosis in Veterinary Medicine (Sims et al., 2003;MacGregor et al., 2005). In light of that, it has been sought to report a case of cardiac lymphoma in an FeLV-positive feline patient.

History
A female feline, with two years of age, weighing three kilos, of a non-defined breed, and castrated, had been referred for treatment in a private veterinary clinic in the city of Patos de Minas/MG-Brazil, upon complaints of apathy, lack of appetite, and progressive weight loss over nearly 15 days. In consultation, the guardian of the animal produced the results of a hemogram performed three days earlier, and the values were within the range deemed as normal for the species.
The patient was subject to clinical examination as per that which is proposed by Feitosa (2014), and the vital parameters were within normality, except for the respiratory and cardiac rates, which were found to be increased. Apart from that, dyspnea was observed and, upon auscultation of the heart region, a muffling was found.
Subsequently, a radiographic examination of the chest had been performed in the ventral-dorsal and right & left lateral positions, which revealed pleural effusion and a general increase in radiopaqueness. The procedure of thoracocentesis was performed with aims at providing respiratory comfort to the patient, though with a small amount of liquid drained. The echocardiogram had been conducted from a Phillips (HD-7) device, with a 3-8 MHz sector transducer, which confirmed the presence of free liquid in the thoracic cavity and highlighted the existence of a major heterogeneous structure attached to the heart ( Figure 1). A sample of the mass was harvested, conditioned into a vial containing aqueous solution of formalin at 10% and, subsequently, forwarded to histopathological analysis. Macroscopically, the fragment appeared brownish, with a soft and uneven surface. Microscopically, an atypical lymphoid proliferation was observed, characterized by small round cells, plasmacytic in aspect, with peripheral hypercolor nuclei -some of them cleaved -and scarce eosinophilic cytoplasm. Numerous apoptotic cells and rare figures of mitosis were also viewed. As from the analysis performed, the diagnosis of lymphoma was defined (Figure 3).
The feline had been subject to a serology test with the Alere™ FIV Ac/FeLV Ag Test Kit, for the qualitative and simultaneous detection of the IgG antibodies of the feline immunodeficiency virus (FIV) and antigens of the feline leukemia virus (FeLV) through full blood samples, which resulted positive for FeLV.
Intravenous support treatment had been instated with fluid therapy at a dosage of 50 ml/kg/day (0.90% Sodium Chloride solution), Tramadol at 1 mg/kg at every eight hours, Dipyrone at 25 mg/kg at every eight hours, and Bionew  at 0.2 ml/kg at every 24 hours.
The patient was forwarded to exploratory surgery in accordance with the technique proposed by Fossum (2014), with aims at the exclusion of the differential diagnosis of diaphragmatic hernia. A wide tricotomy of the abdominal ventral and of the thoracic lateral & ventral regions was performed, with the subsequent antisepsis of that area with 1% Chlorhexidine. The anesthetic induction was carried out intravenously with Propofil at 5 mg/kg, and the general anesthetic maintenance with inhaled Isoflurane. The thoracic opening revealed a significant amount of free liquid and, also, a large mass attached to the cardiac bottom (Figure 2). During the suction of the intrathoracic liquid, the animal had a cardiopulmonary arrest and died.

Discussion
In this report, a cardiac lymphoma was diagnosed in a female feline of non-defined breed, with two years of age. In accordance with the literature, this type of neoplasia is rarely occurring in felines (Buchanan, 1992) and, hence there is not much data in regard of the matter, it is believed that a predisposition of gender or race is non-existent for this disease. According to Ettinger (2003), Vail (2007), and Taylor et al. (2009), cats which have mediastinal lymphoma are often young and FeLV-positive.
In this report, the patient was FeLV-positive and presented dyspnea as the most serious clinical sign. Eleutério (2014) reported the occurrence of a lymphoma around the cardiac bottom of a three-year-old male feline who was also tested positive for FeLV; Amati et al. (2014) reported pericardial lymphoma in seven felines with an average of five years of age, being only one negative for FeLV; Anai et al. (2013) reported a primary cardiac lymphoma in a bitch with eight years of age; and Cápua et al. (2005) reported a mediastinal lymphoma in a two-year-old male feline. In all of the reports considered, the symptomatologic picture of the animals would be similar to that of the feline in this report. The manifestation of apathy, anorexia, and loss of weight observed in this report also corroborate the findings of Cápua et al. (2005), Anai et al. (2013), Amati et al. (2014) and Eleutério (2014). The acute onset of regurgitation or cough is also normally observed in felines with mediastinal lymphoma (Couto, 2000). Other clinical signs described include intolerance to exercise or reluctance to move, tachypnea and dyspnea, cyanosis, dehydration, weak femoral pulse, syncope and cachexia (Cardoso et al., 2004;Amati et al., 2014).
The dyspnea observed in the patient under debate had been a result of the picture of pleural effusion, and it was subject to the technique of thoracocentesis, which aimed at its overall stabilization so the diagnostic and surgical procedures could be performed. The neoplasias are important causes of pleura effusion in small-sized animals (Alleman, 2003) and they must be deemed as a medical emergency, hence they reveal the presence of some severe affection which poses a risk to the health of the animal (Souza, 2013).
Radiography was the first imagery examination performed, as pointed out by Holzworth (1987). The presence of the mass and the dorsal deflection of the trachea -important alterations for the suspicion of intrathoracic neoplasia (Holzworth, 1987) -have not been identified in the patient of this report, upon the presence of pleural effusion. A more directed diagnosis was possible after echocardiography was resorted.
In respect of the tumoral relation with the FeLV, Mackey (1975) believes that this virus is responsible for the occurrence of several hematopoietic neoplasias in cats, being regarded as the main causing agent of feline lymphoma in the European and the North-American continents (Court et al., 1997). Helfand & Vail (1998) believe that 70% of the feline lymphomas have their cause associated to the feline leukemia virus, even in spite of there being a high rate of lymphomas in FeLV-negative cats (Sherding, 2008). The diagnosis of cardiac lymphoma was reached through histopathological examination, which, in accordance with Morrison (2005), is the only means of classifying the tumor properly, even if the fine-needle aspiration biopsy may also render conclusive diagnosis. Such exam, when compared to histology, presents high accuracy in the diagnosis of neoplasias in dogs and cats (Ménard et al., 1986;Ghisleni et al., 2006), but it could not be performed due to the low amount of liquid harvested in the procedure of thoracocentesis.
In cats, and in dogs as well, due to its being a systemic disease, chemotherapy is the treatment of choice for the majority of the presentations of lymphoma (Ettinger, 2003), and most patients attain full remission and present good quality of life . However, the therapeutic protocol used is not the most important prognostic factor but, rather, the concomitant infection by the feline leukemia virus (Jarrett, 1975), which could have been a determining factor for the non-survival of the animal in question.

Conclusion
The cardiac lymphoma was associated to the feline leukemia virus and, in spite of the complementary exams' having been utterly important for a correct diagnosis, the lack of an early definition of the same aggravated the clinical picture of the patient and hindered the implementation of a specific treatment.