Lymph nodes & spleen, nonlymphoma

Lymph nodes-infectious / parasitic disorders

Cat scratch disease



Minor changes: 4 October 2021

Copyright: 2003-2021, PathologyOutlines.com, Inc.

PubMed Search: Cat scratch disease[TI] "last 5 years"[DP]

Laura Brown, M.D.
Elizabeth Courville, M.D.
Page views in 2020: 13,009
Page views in 2021 to date: 13,172
Cite this page: Brown L, Courville E. Cat scratch disease. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lymphnodescatscratch.html. Accessed October 25th, 2021.
Definition / general
  • Majority of cases are caused by Bartonella henselae acquired via arthropod vector (cat flea) or inoculation by cat scratch (Pediatr Infect Dis J 2021;40:S11)
  • Cutaneous red papule 3 - 10 days after contact that may become crusted or pustular, with subsequent development of regional lymphadenopathy 1 - 2 weeks later
  • Histology is characterized by necrotizing stellate abscesses surrounded by palisading histiocytes
  • Usually resolves spontaneously; rare cases may require treatment with antimicrobial therapy
Essential features
  • Typically self limited lymphadenitis caused by Bartonella henselae and transmitted by cats
  • Cutaneous lesion followed by usually localized lymphadenopathy
  • Lymph node histopathology characterized by necrotizing stellate abscesses surrounded by palisading histiocytes
  • Organism stains with Warthin-Starry or specific immunohistochemistry; confirmation by serology or PCR
ICD coding
  • ICD-10: A28.1 - cat scratch disease
Epidemiology
Sites
  • Skin: cutaneous red papule or wheal that may become crusted or pustular
  • Lymph nodes, most commonly upper extremity, followed by cervical and inguinal; patients may have involvement of 1 or multiple lymph node sites (Pediatr Infect Dis J 2021;40:S11)
  • Liver, spleen or bone
  • Rarely, CNS, eye, hematologic involvement / complications (Eur J Intern Med 2005;16:610)
  • Parinaud oculoglandular syndrome: follicular conjunctivitis and regional lymphadenopathy, possibly caused by direct conjunctival inoculation (Ocul Immunol Inflamm 2014;22:148)
Etiology
  • Majority of cases are caused by Bartonella henselae, harbored by kittens and young cats; transmitted between cats by the cat flea (Am J Clin Pathol 1994;101:607)
  • Up to 100% of cat fleas harbor Bartonella and it can also often be detected in cat saliva, blood, skin, claws and feces
  • Most important risk factors are owning a kitten and being bitten, scratched or licked by a kitten harboring fleas; however, up to 25% of patients with cat scratch disease do not report contact with cats
Diagrams / tables

Images hosted on other servers:

Algorithm for cat scratch disease diagnosis

Clinical features
Diagnosis
Radiology description
  • Regional lymphadenopathy
  • Liver and spleen granulomas
Prognostic factors
Case reports
Treatment
Clinical images

Images hosted on other servers:

Retroauricular lymph node enlargement

Cervical lymphadenopathy and primary lesion

Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Elizabeth Courville, M.D. and Mark R. Wick, M.D.
Missing Image Missing Image Missing Image

Suppurative granulomas

Missing Image

Palisading histiocytes

Missing Image

Lymph node biopsy

Missing Image

Steiner stain

Cytology description
Positive stains
Negative stains
Electron microscopy description
  • Extracellular bacteria form small groups within bundles of collagen fibrils
  • Bacteria are gram negative pleomorphic rods, with thick and homogeneous cell walls (Am J Clin Pathol 1987;87:739)
Molecular / cytogenetics description
Sample pathology report
  • Cervical lymph node, excision:
    • Necrotizing granulomatous lymphadenitis (see comment)
    • Comment: The lymph node architecture is distorted by frequent stellate necrotizing granulomas with occasional multinucleated giant cells. Bacterial structures are identified by both Warthin-Starry stain and immunohistochemistry for B. henselae. The overall features are in keeping with cat scratch lymphadenitis, a condition that is generally self limited in immunocompentent patients.
Differential diagnosis
Board review style question #1

A 10 year old girl presents with an enlarged, tender axillary lymph node. An excisional biopsy is performed with findings shown. Which of the following is a likely clinical history for this patient?

  1. Asthma, peripheral blood eosinophilia and elevated serum IgE
  2. Drenching night sweats, petechial rash and peripheral blood cytopenias
  3. Fever, pharyngitis, splenomegaly and positive monospot (heterophile antibody) test
  4. Low grade fever and fatigue, new kitten in the household
Board review style answer #1
D. Low grade fever and fatigue, new kitten in the household. The image shows multiple well formed suppurative granulomas. A relatively common cause of these morphologic findings is cat scratch disease, lymphadenitis transmitted by cats, almost always caused by B. henselae. Most patients with cat scratch disease are under the age of 18 and have recent exposure to a cat, with tender lymphadenopathy appearing in the draining lymph nodes from the site of a scratch. Fever, pharyngitis, splenomegaly and positive monospot (heterophile antibody) test (answer C) describes the classic presentation of infectious mononucleosis. Drenching night sweats, petechial rash and peripheral blood cytopenias (answer B) is more suggestive of a malignant process. Asthma, peripheral blood eosinophilia and elevated serum IgE (answer A) can be seen in Kimura disease.

Comment Here

Reference: Cat scratch disease
Board review style question #2

Excisional lymph node biopsy from a 20 year old man shows the findings seen in the image. Which of the following is the most likely diagnosis?

  1. Cat scratch lymphadenitis
  2. Kimura disease
  3. Progressive transformation of germinal centers
  4. Treponema pallidum
Board review style answer #2
A. Cat scratch lymphadenitis. The image demonstrates lymphadenopathy with suppurative granulomas, a feature that can be seen in cat scratch lymphadenitis. Special stains (silver stain) or organism specific immunohistochemistry on tissue sections may be helpful. Clinical correlation (anatomic distribution of lymphadenopathy, presence of risk factors, such as contact with cats, etc.) and infectious disease workup (serologic studies and culture) are helpful. Kimura disease demonstrates prominent eosinophilic infiltration. Progressive transformation of germinal centers is characterized by indistinct germinal centers invaded by mantle zone cells. Treponema pallidum lymphadenopathy is characterized by plasmacytosis and capsular fibrosis.

Comment Here

Reference: Cat scratch disease
Back to top
Image 01 Image 02