Lymph nodes - not lymphoma
Infectious / parasitic disorders
Cat scratch disease

Author: William D. DePond, M.D. (see Authors page)

Revised: 2 July 2018, last major update July 2013

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Cat-scratch disease [title] lymph nodes

Cite this page: DePond, W. D. Cat scratch disease. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lymphnodescatscratch.html. Accessed August 17th, 2018.
Definition / general
  • Caused by Bartonella (formerly Rochalimaea) henselae (Am J Clin Pathol 1994;101:607), harbored by kittens and young cats; transmitted between cats by cat flea (but not from cats to humans)
  • Adults or children (85% under age 18) infected by cat claws contaminated with infected flea feces; 24K cases / year in US (most common cause of chronic benign lymphadenopathy)
  • Cutaneous red papule 7 - 12 days after contact that may become crusted or pustular, with enlargement of cervical or axillary nodes
  • May have necrotizing granulomas in liver, spleen or bone
  • Usually resolves spontaneously; erythromycin or other macrolides may be given
  • Rare complications are granulomatous conjunctivitis, thrombocytopenic purpura, CNS disease (Eur J Intern Med 2005;16:610)
Historical criteria
  • Exposure to cat and presence of scratch or dermal / eye lesion
  • Positive cat scratch disease antigen skin test
  • Regional lymphadenopathy with negative culture for other possible causes
  • Characteristic changes in nodal biopsy
Case reports
Gram stain
  • Pleomorphic, curved, gram negative coccobacillus
  • Catalase negative, oxidase negative
  • Difficult to culture, but prolonged incubation is helpful (J Clin Microbiol 2002;40:3620)
Gross images

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Lesion on finger

Microscopic (histologic) description
  • Early - histiocytes and follicular hyperplasia
  • Intermediate - capsulitis and subcapsular granulomas
  • Late - abscesses
  • In general, necrosis is often stellate with neutrophils, surrounded by palisading histiocytes
  • Paracortical vascular proliferation
  • Sinuses are often packed with monocytoid B cells, but no epithelioid cells are present
  • Small rods may be present with silver stain around small blood vessels and lymphatics
  • Skin shows dermal necrosis surrounded by histiocytes
  • Also multinucleated giant cells, lymphocytes and eosinophils
Microscopic (histologic) images

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Lymph node biopsy - contributed by Dr. Mark R. Wick

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Steiner stain - contributed by Dr. Mark R. Wick



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Necrotizing granulomas surrounded by palisading histiocytes

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Various images as part of case history

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Warthin-Starry stain

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Immunofluorescence

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Figures 1/2: stellate-shaped abscess with central necrosis
and neutrophils, surrounded by granulomatous inflammation
3: Warthin-Starry stain (also inset) highlights bacteria
4: immunohistochemical stain is also positive

Positive 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)
Differential diagnosis