Hepatic granulomas associated with brucellosis

* Corresponding author at: Ayse Albayrak, Department of Clinical Bacteriology and Infectious Diseases, Erzurum Region Education and Research Hospital, Erzurum, Turkey. Tel: +90-44223255 61, Fax: + 90-4422325090. E-mail address: [email protected] Brucellosis, a bacterial disease caused by members of the genus Brucella, remains one of the most common zoonotic diseases worldwide (1-3). The disease occurs in both animals and humans, except in those countries where bovine Brucellosis has been eradicated (1). The bacterial pathogen is classified by the CDC as a category-B pathogen that has potential for development as a bioterrorist agent (1, 4). Brucella spp. is considered to be the most common laboratory-acquired pathogen (1, 5). In humans, Brucellosis behaves as a systemic infection with a very heterogeneous clinical spectrum (2, 3, 6). The Brucella organism’s predilection for organs rich in reticuloendothelial cells (spleen, liver, bone marrow, lymph nodes) and its intracellular location are responsible for the chronicity of the disease, which can last for months or even years (1, 2, 7). Brucella has been reported to compromise the central and peripheral nervous system, as well as the gastrointestinal, hepatobiliary, genitourinary, musculoskeletal, cardiovascular, and integumentary systems (2). In patients with Brucellosis, the gastrointestinal system is commonly compromised (70%) (5). Because the liver is the largest organ of the reticuloendothelial system and plays the important role of defense mechanism against Brucella infections, diffuse hepatic involvement is usually recorded during the course of human Brucellosis infection (8). Brucellosis involves the liver in varying ways, including a slight increase in transaminase levels, mild hepatosplenomegaly, chronic suppurative disease, and, more rarely, acute hepatitis (5, 8-13). In patients infected with Brucella melitensis, the involvement of bile canals is observed more often than other Brucellosis factors (14). Hepatic granulomas are often encountered during liver biopsy and can be caused by a variety of conditions such as a primary hepatic process, fever of unknown origin, or a manifestation of a systemic illness (15, 16). Granulomas are reportedly present in 2 to 10% of all liver-biopsy specimens examined in general practice (17). Liver Brucelloma, or pseudotumoral necrotizing granuloma, is an uncommon type of hepatic manifestation by Brucella and is observed in only 1.7% of patients affected by Brucellosis (8). Hepatic Brucelloma is rarely the first to manifest itself clinically, and a focal suppurative lesion may occur if acute Brucellosis is undetected or undertreated in the patient (18). Granulomas are aggregates of macrophages, often admixed with other inflammatory cells, which usually result from a chronic presence of antigens. Granulomas are a unique inflammatory response that may be idiopathic or may be a response to a bacterial, fungal, viral, or parasitic infection, in the latter cases representing a manifestation of underlying malignancy (15, 17).The pathology report on Brucelloma usually shows necrotizing granulomas with a peripheral halo of epithelioid cells. lymphocytes, and plasma cells, as well as and a polimorphonuclear infiltrate in the necrotic area (19-21). Brucellosis involving Brucella abortus is the most common species that can cause hepatic granulomas that are indistinguishable from sarcoidosis (13, 16), and Brucella abortus is the most common species that can cause hepatic granulomas. Histopathologically, histiocytic granulomas are present, often with central necrosis, portal and peripheral infiltration, and hyperplasia of the Kupffer cells. (11, 22, 23). These granulomas result from the caseation of a granulomatous reaction by persistent Brucellae within macrophages. At present, approximately thirty cases of granulomatous hepatitis (hepatic Brucelloma) have been reported in the literature (19, 23, 24). The clinical and biochemical abnormalities return to normal after appropriate treatment (25). Diagnosis is based on the association of imaging c 2011 Kowsar M.P.Co. All rights reserved. Hepatic granulomas associated with brucellosis