JPC SYSTEMIC PATHOLOGY
Signalment (AFIP Accession #2145819): Human, 27 year-old, sex unspecified
HISTORY: This veterinarian had a history of recent lymphadenopathy of the right axillary lymph node.
H-B09a: Lymph node, right axillary:
Effacing approximately 50% of the nodal architecture, primarily within the cortex and paracortical areas, are multifocal to coalescing pyogranulomas, characterized by a central core of eosinophilic cellular and karyorrhectic debris (lytic necrosis), surrounded by and admixed with moderate numbers of viable and degenerate neutrophils with fewer macrophages, including epithelioid macrophages and rare multinucleated giant cells, few fibroblasts and fibrin. The remainder of the cortex is moderately hyperplastic with a few secondary follicles and expansion of the paracortical areas. Medullary sinuses contain many histiocytes and there are multifocal areas of hemorrhage within the capsule, cortex, and medulla.
Warthin-Starry: Multifocally, primarily within areas of necrosis, there are rare extracellular, silver-positive, 2 x 3 um bacilli.
MORPHOLOGIC DIAGNOSIS: Lymph node, right axillary: Lymphadenitis, pyogranulomatous and necrotizing, multifocal to coalescing, moderate, with rare agyrophylic pleomorphic bacilli, human.
ETIOLOGIC DIAGNOSIS: Bartonella lymphadenitis
CAUSE: Bartonella henselae
CONDITION: Cat scratch disease (CSD)
- Bartonella henselae is a gram-negative, fastidious, intracellular bacterial pathogen that infects erythrocytes, endothelial cells and macrophages.
- Cats are rarely affected by clinical disease and the exact pathogenesis has not been elucidated
- Infection is transmitted by various-blood sucking arthropods
- Many Bartonella spp can induce activation of hypoxia-inducible factor-1 and production of vascular endothelial growth factor. This may contribute to the organism’s ability to induce endothelial cell proliferation.
TYPICAL CLINICAL FINDINGS:
- Regional lymphadenopathy, fever, malaise, fatigue, myalgia, arthralgia, skin eruptions, weight loss, and splenomegaly
- Spontaneous resolution occurs in most cases after several weeks to months
TYPICAL GROSS FINDINGS:
- Single-node or regional lymphadenopathy, usually of arms, head, or neck; +/ suppuration
TYPICAL LIGHT MICROSCOPIC FINDINGS:
- Hyperplasia of lymphoid organs
- Foci of lymphocytic, pyogranulomatous inflammation in multiple tissues i.e. lung, liver, spleen, kidney, heart +/- necrotic areas
- Pyogranulomatous endocarditis and myocarditis
- Infections often self-limiting but persistent intravascular infection reported
- Lesions associated with Bartonella include:
- Endocarditis (Vegetative valvular)
- Granulomatous lymphadenitis, hepatitis, panniculitis
- Peliosis hepatitis
- Anterior uveitis
- Haemolytic anemia
- Lesions associated with Bartonella include:
ADDITIONAL DIAGNOSTIC TESTS:
- henselae is increasingly recognized as a cause of both pyogranulomatous myocarditis and endocarditis, with diaphragm often an additional feature
- henselae and B. clarridgeae are associated with self-limiting illness and persistent intravascular infection
- vinsonii has been reported to cause hematogenous osteomyelitis
- Bartonella have been associated with endocarditis
- Bartonella vinsonii subsp berkhoffi has been reported in 3 dogs with pyogranulomatous meningoradiculoneuritis and multiple pyogranulomatous nodular dermatitis or panniculitis
- Bartonella spp. have been associated with myocarditis, endocarditis, pyogranulomatous lymphadenopathy, uveitis, polyarthritis, meningoencephalitis, thrombocytopenia, and bacillary angiomatosis
- Breitschwerdt EB, Linder KL, Day MJ et al. Koch’s postulates and the pathogenesis of comparative infectious disease causation associated with Bartonella species. J Comp Pathol. 2013;148(2-3):115-125.
- Buchmann AU, Kempf VAJ, Kershaw O, Gruber AD. Peliosis hepatis in cats is not associated with Bartonella henselae infections. Vet Pathol. 2010;47:163-166.
- Craig LE, Dittmer KE, Thompson KG. Bones and joints. In: Maxie MG, Ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St Louis, MO: Elsevier; 2016: 99.
- Cullen JM, Stalker MJ. Livery and biliary system. In: Maxie MG, Ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St Louis, MO: Elsevier; 2016: 318
- Mauldin EA, Peters-Kennedy J. Integumentary system. In: Maxie MG, Ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 1. 6th ed. St Louis, MO: Elsevier; 2016: 646.
- Pultorak EL, Linder K, Maggi RG et al., Prevalence of Bartonella spp in canine cutaneous histiocytoma. J Comp Pathol. 2015:153: 14-21.
- Robinson WF, Robinson NA. Cardiovascular system. In: Maxie MG, Ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St Louis, MO: Elsevier; 2016: 31,42
- Varanat M, Broadhurst J, Linder KE, et al. Identification of Bartonella henselae in 2 cats with pyogranulomatous myocarditis and diaphragmatic myositis. Vet Pathol. 2012; 49(4):608-611.