A dog with a splenic mass may present as overtly healthy; have vague signs of anorexia, lethargy, and vomiting; or be in hemorrhagic shock. While many variables have been investigated, none definitively distinguish between the most common splenic masses: hematoma, hemangioma, and hemangiosarcoma (HSA). Since ultrasound-guided fine-needle aspirate or incisional biopsy of a splenic mass carries significant risk of hemorrhage and a nondiagnostic sample, definitive diagnosis is most commonly made via histopathology after splenectomy. Thus, clients are faced with a dilemma: Do they invest in a surgery that could potentially cure their dog, knowing there is also the risk their pet may be left with the onus of HSA? The client’s decision may be aided by diagnostics to assess the patient’s current condition and look for potential metastases, and by considering the dog’s hemoabdomen status (BOX 1).
- In the absence of hemoabdomen, there is a high likelihood the splenic mass is benign; in the presence of hemoabdomen, there is a high likelihood the mass is malignant1-4
- Purposes of diagnostics
- Assess patient status, treatment needs, and suitability for surgery
- Look for metastases
- Cannot make definitive diagnosis without histopathology1,2
- Prognosis/median survival time
- Hemangiosarcoma with surgery alone: 19–86 days with 1-year survival of 6%–7%5-9
- Hemangiosarcoma with surgery and chemotherapy: 172–277 days with 1-year survival up to 20%1,6,8,9
- If mass is benign, surgery can be curative
- 95% of dogs with hemoabdomen survived to discharge postsplenectomy3,4
- Presence of splenic mass is a risk factor for life-threatening hemorrhage
There is a 63.1% to 70.5% chance a splenic mass is benign if there is no hemoabdomen and a 21.7% to 37.5% chance it is benign if there is hemoabdomen.1-4 These numbers replace the two-thirds rule, which said that two-thirds of splenic masses were malignant and two-thirds of malignant masses were HSA, without accounting for hemoabdomen. Despite the high incidence of HSA in dogs with hemoabdomen, clients may pursue treatment (BOX 2). One study found that clients who chose surgery were more satisfied with their decision than those who elected palliation or euthanasia, and quality of life scores were higher for dogs that had surgery compared to palliative care.5 Ultimately, it is important to educate the client about the potential for both positive and negative outcomes.
- Potential for cure if the mass is not hemangiosarcoma
- Treat and/or prevent hemoabdomen
- Obtain a diagnosis
- Debulk in preparation for chemotherapy
- Provide family more time with their dog
References
1. Schick AR, Grimes JA. Evaluation of the validity of the double two-thirds rule for diagnosing hemangiosarcoma in dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass: a systematic review. JAVMA. 2023;261(1):69-73. doi:10.2460/javma.22.08.0389
2. Cleveland MJ, Casale S. Incidence of malignancy and outcomes for dogs undergoing splenectomy for incidentally detected nonruptured splenic nodules or masses: 105 cases (2009-2013). JAVMA. 2016;248(11):1267-1273. doi:10.2460/javma.248.11.1267
3. Michael AE, Grimes JA, Rajeev M, et al. Perioperative ventricular arrhythmias are increased with hemoperitoneum and are associated with increased mortality in dogs undergoing splenectomy for splenic masses. JAVMA. Published online August 29, 2023;261(12):1-6. doi:10.2460/javma.23.05.0289
4. Stewart SD, Ehrhart EJ, Davies R, Khanna C. Prospective observational study of dogs with splenic mass rupture suggests potentially lower risk of malignancy and more favourable perioperative outcomes. Vet Comp Oncol. 2020;18(4):811-817. doi:10.1111/vco.12621
5. Menard JV, Sylvester SR, Lopez DJ. Assessing major influences on decision-making and outcome for dogs presenting emergently with nontraumatic hemoabdomen. JAVMA. 2023;261(7):980-988. doi:10.2460/javma.23.01.0014
6. Burgess KE, Price LL, King R, et al. Development and validation of a multivariable model and online decision-support calculator to aid in preoperative discrimination of benign from malignant splenic masses in dogs. JAVMA. 2021;258(12):1362-1371. doi:10.2460/javma.258.12.1362
7. Fleming J, Giuffrida MA, Runge JJ, et al. Anatomic site and etiology of hemorrhage in small versus large dogs with spontaneous hemoperitoneum. Vet Surg. 2018;47(8):1031-1038. doi:10.1111/vsu.12963
8. Rosenthal RC, Smrkovski O, Rothrock K. Hemangiosarcoma, splenic (canine). VIN. May 8, 2021. Accessed May 3, 2024. https://www.vin.com/members/cms/project/defaultadv1.aspx?pid=607&id=4954038&f5=1
9. Veterinary Society of Surgical Oncology. Splenic HSA – canine. Accessed May 3, 2024. https://vsso.org/splenic-hsacanine
10. Clendaniel DC, Sivacolundhu RK, Sorenmo KU, et al. Association between macroscopic appearance of liver lesions and liver histology in dogs with splenic hemangiosarcoma: 79 cases (2004–2009). JAAHA. 2014;50(4):e6-e10. doi:10.5326/JAAHA-MS-6059
11. Aronsohn MG, Dubiel B, Roberts B, Powers BE. Prognosis for acute nontraumatic hemoperitoneum in the dog: a retrospective analysis of 60 cases (2003–2006). JAAHA. 2009;45(2):72-77. doi:10.5326/0450072