Mast Cell Tumors in Cats

Skeldon NC, Gerber KL, Wilson RJ et al: Mastocytaemia in cats: prevalence, detection and quantification methods, haematological associations and potential implications in 30 cats with mast cell tumours, J Feline Med Surg 12:960, 2010.

Mast cell tumors (MCT) exhibit a different biologic behavior in cats than in dogs. Most authors believe the majority of tumors are benign in cats. Mastocytemia, large numbers of mast cells in the blood, appears exclusively associated with MCT in cats. In this study, it was found that 43% of the cats examined with mast cell disease had mastocytemia. Direct blood film examination and/or buffy coat (BC) preparations from blood are the primary methods used to diagnose mastocytemia. BC examination was considered the best screening method for detection while direct blood film examination was more accurate in detecting the degree of mastocytemia. The authors believe BC examination should be mandatory in all known or suspected cases of MCT, or in cats with splenomegaly or vomiting of undetermined cause. Additional findings in this study were that 10% of cats had concurrent cutaneous and visceral MCT. Also, mastocytemic cats with MCT had a significantly lower hematocrit than cats without mastocytemia. [VT]

Related articles: Sabattini S, Bettini G: Prognostic value of histologic and immunohistochemical features in feline cutaneous mast cell tumors, Vet Pathol 47:643, 2010.

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Skeldon NC, Gerber KL, Wilson RJ et al: Mastocytaemia in cats: prevalence, detection and quantification methods, haematological associations and potential implications in 30 cats with mast cell tumours, J Feline Med Surg 12:960, 2010.

Mast cell tumors (MCT) exhibit a different biologic behavior in cats than in dogs. Most authors believe the majority of tumors are benign in cats. Mastocytemia, large numbers of mast cells in the blood, appears exclusively associated with MCT in cats. In this study, it was found that 43% of the cats examined with mast cell disease had mastocytemia. Direct blood film examination and/or buffy coat (BC) preparations from blood are the primary methods used to diagnose mastocytemia. BC examination was considered the best screening method for detection while direct blood film examination was more accurate in detecting the degree of mastocytemia. The authors believe BC examination should be mandatory in all known or suspected cases of MCT, or in cats with splenomegaly or vomiting of undetermined cause. Additional findings in this study were that 10% of cats had concurrent cutaneous and visceral MCT. Also, mastocytemic cats with MCT had a significantly lower hematocrit than cats without mastocytemia. [VT]

Related articles: Sabattini S, Bettini G: Prognostic value of histologic and immunohistochemical features in feline cutaneous mast cell tumors, Vet Pathol 47:643, 2010.

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Splenectomy in Cats

Gordon SSN, McClaran JK, Bergman PJ et al: Outcome following splenectomy in cats, Journal of Feline Medicine & Surgery 12:256, 2010.

A complete splenectomy is indicated as a treatment for suspected malignant neoplasia or generalized splenic enlargement secondary to infiltrative disease of the spleen. The most common splenic diseases in cats are mast cell tumors (MCTs), lymphoma, and myeloproliferative disease. There have been no studies that examine prognostic factors for survival of cats undergoing splenectomy.  The medical records of 19 cats were reviewed for this study. The most common reasons for splenectomy in these cats were MCTs (53%), hemangiosarcoma (21%), and lymphoma (11%). A number of studies, including this one, indicate systemic mastocytosis with splenic involvement appears to be the most common cause of spenomegaly and splenic disease in domestic cats. Anorexia, significant weight loss, and male gender have been shown to be negative prognostic indicators for cats with splenic MCTs.  Three cats in this study had preoperative weight loss and this was the only factor identified as a prognostic indicator of survival following surgery. The median survival time for cats with weight loss was 3 days. In cats with no weight loss, the median survival time was 293 days. [VT]

Related articles:
Litster AL, Sorenmo KU: Characterisation of the signalment, clinical and survival characteristics of 41 cats with mast cell neoplasia, J Feline Med Surg 8:177, 2006.

More on cat health: Winn Feline Foundation Library
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Gordon SSN, McClaran JK, Bergman PJ et al: Outcome following splenectomy in cats, Journal of Feline Medicine & Surgery 12:256, 2010.

A complete splenectomy is indicated as a treatment for suspected malignant neoplasia or generalized splenic enlargement secondary to infiltrative disease of the spleen. The most common splenic diseases in cats are mast cell tumors (MCTs), lymphoma, and myeloproliferative disease. There have been no studies that examine prognostic factors for survival of cats undergoing splenectomy.  The medical records of 19 cats were reviewed for this study. The most common reasons for splenectomy in these cats were MCTs (53%), hemangiosarcoma (21%), and lymphoma (11%). A number of studies, including this one, indicate systemic mastocytosis with splenic involvement appears to be the most common cause of spenomegaly and splenic disease in domestic cats. Anorexia, significant weight loss, and male gender have been shown to be negative prognostic indicators for cats with splenic MCTs.  Three cats in this study had preoperative weight loss and this was the only factor identified as a prognostic indicator of survival following surgery. The median survival time for cats with weight loss was 3 days. In cats with no weight loss, the median survival time was 293 days. [VT]

Related articles:
Litster AL, Sorenmo KU: Characterisation of the signalment, clinical and survival characteristics of 41 cats with mast cell neoplasia, J Feline Med Surg 8:177, 2006.

More on cat health: Winn Feline Foundation Library
Join us on Facebook
Follow us on Twitter

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Treatment for Mast Cell Tumors in Cats

Rassnick, K. M., L. E. Williams, et al. (2008). "Lomustine for treatment of mast cell tumors in cats: 38 cases (1999-2005)." J Am Vet Med Assoc 232(8): 1200-5.


Mast cell tumours (MCTs) are commonly diagnosed in cats, particularly in cutaneous locations. These tumours have a range of biological behavior from benign to malignant. Most cutaneous MCTs are readily treated with surgery or local radiation. Alternative treatments are needed for those cats where surgery or radiation is not an option, or where these modalities have failed to prevent recurrence. In this retrospective case series, the clinical efficacy and toxicity of lomustine was evaluated in 38 cats with confirmed mast cell tumors. Lomustine was administered at a dose at or equal to 50 mg/m(2). Of the 38 cats, most (68%) had cutaneous MCTs but tumors were also diagnosed in other locations, such as mesenteric lymph nodes. The overall response rate was 50%, with 7 cats having a complete response. The median duration of response was 168 days. The most commonly noted toxicoses were neutropenia and thrombocytopenia. The researchers conclude that lomustine should be considered for cats with MCTs where local treatment is not an option.
>> PubMed abstract


Related articles:
Turrel, J., J. Farrelly, et al. (2006). "Evaluation of strontium 90 irradiation in treatment of cutaneous mast cell tumors in cats: 35 cases (1992-2002)." J Amer Vet Med Assoc 228(6): 898-901.
>> PubMed abstract


More on cat health: Winn Feline Foundation Library

Rassnick, K. M., L. E. Williams, et al. (2008). "Lomustine for treatment of mast cell tumors in cats: 38 cases (1999-2005)." J Am Vet Med Assoc 232(8): 1200-5.


Mast cell tumours (MCTs) are commonly diagnosed in cats, particularly in cutaneous locations. These tumours have a range of biological behavior from benign to malignant. Most cutaneous MCTs are readily treated with surgery or local radiation. Alternative treatments are needed for those cats where surgery or radiation is not an option, or where these modalities have failed to prevent recurrence. In this retrospective case series, the clinical efficacy and toxicity of lomustine was evaluated in 38 cats with confirmed mast cell tumors. Lomustine was administered at a dose at or equal to 50 mg/m(2). Of the 38 cats, most (68%) had cutaneous MCTs but tumors were also diagnosed in other locations, such as mesenteric lymph nodes. The overall response rate was 50%, with 7 cats having a complete response. The median duration of response was 168 days. The most commonly noted toxicoses were neutropenia and thrombocytopenia. The researchers conclude that lomustine should be considered for cats with MCTs where local treatment is not an option.
>> PubMed abstract


Related articles:
Turrel, J., J. Farrelly, et al. (2006). "Evaluation of strontium 90 irradiation in treatment of cutaneous mast cell tumors in cats: 35 cases (1992-2002)." J Amer Vet Med Assoc 228(6): 898-901.
>> PubMed abstract


More on cat health: Winn Feline Foundation Library

Read More