Rice and Sutter Journal of Medical Case Reports 2010, 4:353 http://www.jmedicalcasereports.com/content/4/1/353 Department of Infectious Disease. Mild splenomegaly was noted, with the specimen weighing 321 g and measuring 14.1 × 9.2 × 6.1 cm. Grossly, the spleen was described to have a smooth, ruptured capsule of unde- termined cause. The red pulp contained a diffuse, mixed infiltrate consisting of variable numbers of small lymphocytes, granulocytes, plasma cells and histiocytes. No infectious organisms were visualized with special staining (Grocott-Gomori methenamine silver nitrate, Brown and Brenn, Brown and Hopps, Fite, Warthin- Starry, periodic acid-Schiff with diastase, Ziehl- Nielsen), and immunohistochemical study results were normal. No significant atypia was identified. Results for serologic testing over the patient’s hospital course and after discharge were negative throughout, including three blood cultures, two urine and throat cultures, stool culture, ova and parasites, fecal leukocytes, two malaria thick and thin smears, HIV-1 Antibody, hepati- tis virus panel, two heterophile Antibody tests, Epstein- Barr Virus Antibody panel and two Leishmania spp. Antibody panels. Before discharge, the patient was offered bone marrow biopsy to further elucidate the cause of his splenic rupture; however, he declined the procedure. The patient currently remains on active duty and at 18-month follow-up reported doing well since discharge, with no known sequelae. Discussion In 1861, Rokitansky first reported atraumatic splenic rupture in a leukemic patient, and in 1874, Atkinson first described the rupture of an apparently normal spleen [1,6]. Since then, several authors have attempted to further delineate the subtypes of atraumatic splenic rupture. It has been proposed that “true spontaneous” or “idiopathic” rupture refer only to spontaneous rup- ture of a normal spleen, and spontaneous rupture of a diseased spleen is most appropriately termed “patholo- gic” or “occult” rupture [3]. “True spontaneous” splenic rupture has been described in the literature, but its validity has often been challenged. Wright and Prigot stated, “There is no such clinical entity as spontaneous rupture of the normal spleen,” [4], implying that thor- ough questioning and investigation will reveal a history of trauma or splenic pathology. After reviewing reports of spontaneous splenic rupture through 1958, Orloff and Peskin [2] found that most cases did have an identi- fiable pathologic or traumatic source. From this review, they proposed four criteria necessary to make the diag- nosis, and in 1991, Crate and Payne [7] added a fifth condition (Appendix 1). Satisfying these criteria makes the diagnosis of “true spontaneous” splenic rupture chal- lenging because investigators must carefully consider all potential causes. Several mechanisms have been pro- posed to explain atraumatic rupture in the absence of Page 3 of 5 Table 1 Some Causes of Pathologic Splenic Rupture [1,3] Infectious Bacterial Staphylococci Streptococci Clostridium spp. Actinomycosis Salmonella spp. Enterobacter spp. Campylobacter spp. Haemophilus spp. Tularemia Brucellosis Legionellosis Tuberculosis Viral Infectious mononucleosis Mumps Hepatitis A Dengue Cytomegalovirus Rubella Varicella-zoster Influenza HIV Other Malaria Leishmaniasis (visceral) Syphilis Echinoccocus spp. Typhus Leptospirosis Q fever Relapsing fever Candidiasis Neoplastic and Hematologic Leukemia Lymphoma Myelofibrosis Multiple myeloma Splenic malignancy Hepatocellular carcinoma Hemophilia Congenital factor XIII deficiency Protein S deficiency Hemolytic anemia Polycythemia Anticoagulant therapy Local splenic causes Splenic cyst Splenic vein thrombosis Splenic peliosis Diffuse splenic angiomatosis Portal hypertension Splenic infarct Miscellaneous Sarcoidosis Amyloidosis Wilson’s disease Gaucher’s disease Cirrhosis Crohn’s disease Polyarteritis nodosa Systemic lupus erythematosus Pancreatitis Rheumatoid arthritis Wegener’s vasculitis disease, primarily focusing on unrecognized sources of trauma or pathology (Appendix 2). Atraumatic splenic rupture of the diseased spleen has been more commonly described and is associated with various infectious, neoplastic, hematologic, metabolic, inflammatory and local splenic disorders (Table 1). Although the cause of our patient’s splenic rupture was undetermined, his clinical presentation was suggestive of an infectious process. As depicted in Table 1, a variety of bacterial, viral and parasitic agents have been reported to cause splenic enlargement and predispose to spontaneous rupture. Of these known pathogens, malaria in particular has been extensively studied because it is estimated to be the primary cause of spon- taneous splenic rupture worldwide [8-11]. Its review illustrates some theories behind pathologic rupture of