{Reference Type}: Systematic Review
{Title}: 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.
{Author}: Schick AR;Grimes JA;
{Journal}: J Am Vet Med Assoc
{Volume}: 261
{Issue}: 1
{Year}: 11 2022 2
{Factor}: 1.836
{DOI}: 10.2460/javma.22.08.0389
{Abstract}: To evaluate the validity of the double two-thirds rule for a diagnosis of splenic hemangiosarcoma in dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass.<BR>Systematic literature review.<BR>3 databases (PubMed, CAB abstracts, and World of Science) were searched in November 2020. Articles were included if data on dogs with nontraumatic hemoperitoneum due to a splenic mass were included and subsequent pathologic diagnosis could be determined.<BR>In total, 2,390 unique articles were identified, with 66 articles meeting the criteria for full-text review and 14 articles included for analysis. A total of 1,150 dogs were evaluated, with 73.0% (840/1,150) of dogs being diagnosed with a malignant splenic lesion and 27.0% (310/1,150) being diagnosed with a benign splenic lesion. Of the malignancies, 87.3% (733/840) were hemangiosarcoma. Levels of evidence were low, and bias was high as most included studies were retrospective case series.<BR>The double two-thirds rule should be refined when evaluating dogs with nontraumatic hemoperitoneum from a ruptured splenic mass, with more dogs being diagnosed with a malignancy and hemangiosarcoma specifically than the double two-thirds rule indicates. These findings may be useful in an emergency setting to guide owners on potential diagnoses for dogs with nontraumatic hemoperitoneum due to a ruptured splenic mass. However, there remains a portion of these dogs with benign conditions and nonhemangiosarcoma malignancies that may have a good long-term prognosis compared to dogs with hemangiosarcoma. Studies with higher levels of evidence, lower risks of bias, and large case numbers are needed in the literature.