Cat scratch disease - a case report

Cat scratch disease is benign self-limiting infectious disease caused by B. Henselae. It can occur world-wide with no racial or sex predilection. Cats are the major reservoirs. Transmission can occur through biting, scratching and licking. Patients present with regional lymphadenopathy. A 17-year-old male presented with a single swelling in the inguinal region of 15 days duration. It was gradually increasing in size. The swelling measured 6cm * 5cm, soft to firm in consistency, non-tender. The mobility was restricted. Fine needle aspiration cytology was performed which was diagnosed as granulomatous lymphadenitis. The swelling was excised and sent for histopathological examination. Histopathologically, a final diagnosis of Cat-scratch lymphadenitis was made. Cat-scratch Disease is a self-limiting illness in an immuno-competent host. The associated lymphadenitis is mainly solitary and unilateral. Although it is not a unique diagnosis, Cat-scratch disease is required to implement appropriate and targeted antibiotic therapy. Key word: Cat scratch disease, Cat scratch disease, cats ................................................................................................................................................................................................... Introduction Cat-scratch disease (CSD) is a benign infectious disease caused by intra-cellular bacterium Bartonella Henselae. It was first discovered by Henri Perinaud in 1889[1]. Healthy young cats are the main reservoir of the disease-causing bacterium. Dogs, rabbits and monkeys are also reservoirs associated with cat scratch disease apart from cats. The disease peaks in fall and winter [2]. Adults or children (85% under age 18) infected by cat claws contaminated with infected flea faeces. CSD is typically a self-limiting illness consisting primarily of regional lymphadenopathy following approximately 1 to 3 weeks after bite. Case report A 17-year-old male presented with a single swelling in the inguinal region of 15 days duration. It was gradually increasing in size. The swelling measured 6cm * 5cm, soft to firm in consistency, non-tender. The mobility was restricted. Fine needle aspiration cytology was performed which showed presence of predominantly histiocytes, lymphocytes and plasma cells along with few epithelioid cell-granulomas. A diagnosis of Granulomatous lymphadenitis was made. Later the involved inguinal lymph-node was excised and tissue was sent for histopathological examination. Gross: Mass was excised measuring 5 cm *3 cm *2cm. External surface showed few grey white nodules largest measuring 0.5cm in diameter. The cut section showed grey-white areas with few areas of haemorrhage. Manuscript received: 10 th April 2018 Reviewed: 20 th April 2018 Author Corrected: 28 th April 2018 Accepted for Publication: 2 nd May 2018 April June, 2018/ Vol 4/ Issue 2 Pathology Update: Tropical Journal of Pathology & Microbiology Figure-A: Clinical picture showed globular mass; External surface showed few grey white nodules. Microscopy: Structure of lymph-node with effacement a aggregates of histiocytes with proliferating blood vessels and ill abscesses were also seen with scattered neutrophils and central eosinophilic necr differential of Tuberculosis, Sarcoidosis, Kikuchi’s disease and Cat FigureC: Microscopy showed structure of lymph node architecture with effacement and aggregates of histiocytes. (4x, H & E stain) Figure-E: Microscopy showed sheets and aggregates of histiocytes with proliferating blood vessels ill-formed granulomas. (40x, H & E stain) Print ISSN: 2456-9887, Online Case Report Available online at: www.pathologyreview.in Figure-B: Cut section showed grey areas with few areas of haemorrhage. nd mild distortion of architecture was seen. Sheets and -formed granulomas were seen in the cortex. Multiple osis and outer rim of epithelioid cells. A -scratch disease was made. FigureD:Microscopy showed areas of eosinophil necrosis. (10x, H & E stain) Figure-F: Microscopy showed scattered forming neutrophils and central necrosis and outer rim of epithelioid cells. (4x, H & E stain) C A


Introduction
Cat-scratch disease (CSD) is a benign infectious disease caused by intra-cellular bacterium Bartonella Henselae. It was first discovered by Henri Perinaud in 1889 [1].
Healthy young cats are the main reservoir of the disease-causing bacterium. Dogs, rabbits and monkeys are also reservoirs associated with cat scratch disease apart from cats. The disease peaks in fall and winter [2]. Adults or children (85% under age 18) infected by cat claws contaminated with infected flea faeces.
CSD is typically a self-limiting illness consisting primarily of regional lymphadenopathy following approximately 1 to 3 weeks after bite.

Case report
A 17-year-old male presented with a single swelling in the inguinal region of 15 days duration. It was gradually increasing in size. The swelling measured 6cm * 5cm, soft to firm in consistency, non-tender.
The mobility was restricted. Fine needle aspiration cytology was performed which showed presence of predominantly histiocytes, lymphocytes and plasma cells along with few epithelioid cell-granulomas.
A diagnosis of Granulomatous lymphadenitis was made.
Later the involved inguinal lymph-node was excised and tissue was sent for histopathological examination.
Gross: Mass was excised measuring 5 cm *3 cm *2cm. External surface showed few grey white nodules largest measuring 0.5cm in diameter. The cut section showed grey-white areas with few areas of haemorrhage.  Microscopy: Structure of lymph-node with effacement a aggregates of histiocytes with proliferating blood vessels and ill abscesses were also seen with scattered neutrophils and central eosinophilic necr differential of Tuberculosis, Sarcoidosis, Kikuchi's disease and Cat node with effacement and mild distortion of architecture was seen. Sheets and aggregates of histiocytes with proliferating blood vessels and ill-formed granulomas were seen in the cortex. Multiple abscesses were also seen with scattered neutrophils and central eosinophilic necrosis and outer rim of epithelioid cells. A differential of Tuberculosis, Sarcoidosis, Kikuchi's disease and Cat-scratch disease was made. Zeihl-Neelson staining was performed which was negative for Acid fast bacilli. Gomori's metha performed which revealed presence of rod shaped and L proliferating vessels. These were suspected to be Bartonella Henselae.

Figure-I: L-shaped bacilli in singles and clumps. (100x oil immersion, GMS stain)
A final diagnosis of Cat-scratch lymphadenitis was made.

Discussion
Cat-scratch disease (CSD) is a common cause of chronic lymphadenopathy among children and adolescents, and the major etiologic agent underlying it is the bacterium Bartonella Henselae [3,4]. CSD was highest among those who lived in the southern United States (6.4 cases/100,000 population) and among children 5-9 years of age (9.4 cases/100,0 population) [5]. Pathogens are transmitted by bites o scratches from infected cats.
These bacterial pathogens are gram negative, pleomorphic small rods occurring in singles or clumps [6]. They are seen within the foci of necrosis,  Neelson staining was performed which was negative for Acid fast bacilli. Gomori's metha performed which revealed presence of rod shaped and L-shaped bacilli in singles, within the areas of necrosis and near proliferating vessels. These were suspected to be Bartonella Henselae.

Microscopy showed presence of rod shaped and shaped bacilli in singles and clumps. (100x oil immersion, GMS stain)
scratch lymphadenitis was made. scratch disease (CSD) is a common cause of chronic lymphadenopathy among children and nts, and the major etiologic agent underlying it [3,4]. Incidence of CSD was highest among those who lived in the southern United States (6.4 cases/100,000 population) 9 years of age (9.4 cases/100,000 Pathogens are transmitted by bites or These bacterial pathogens are gram negative, pleomorphic small rods occurring in singles or in [6]. They are seen within the foci of necrosis, vessel walls and in the vicinity of collagen fibres. The bacilli are best stained Warthin impregnation stain [6,7]. diagnosis of CSD have been exposure to cat bite or scratch, an inoculation site, regional lymphadenopathy, typical histopathology on lymph node biopsy, negative tests for other infections, and a positive delayed hypersensitivity skin test using CSD antigen.
Most of the patients presents with erythematous patch in affected area, this is followed by a papular and then a vesicular lesion which oozes fluid. he vicinity of collagen fibres. The bacilli are best stained Warthin-Starry silver The major criteria for diagnosis of CSD have been exposure to cat bite or scratch, an inoculation site, regional lymphadenopathy, ology on lymph node biopsy, negative tests for other infections, and a positive delayed hypersensitivity skin test using CSD antigen.
Most of the patients presents with erythematous patch in affected area, this is followed by a papular and then a r lesion which oozes fluid. The lesion then dries to form a scab. Usually a unilateral lymphadenitis near H Case Report Pathology Update: Tropical Journal of Pathology & Microbiology Available online at: www.pathologyreview.in 170 | P a g e the scratch, bite site develops 2-3 weeks after infection, which is usually in the head, neck, axilla, or supraclavicular region. Atypical manifestations include mammary, oculo-glandular, hepatosplenic, cardiopulmonary, central nervous system, and bone involvement.
The present case also came with unilateral and single palpable inguinal lymph node [8]. Cat-scratch lymphadenopathy is characterized by enlarged and matted lymph nodes which are usually adherent to the surrounding soft tissues [8,9]. This may be the cause of restricted mobility as seen in the present case.
On gross examination, the lymph node is enlarged with multiple abscesses over the surface, appearing as small nodules. This type of picture was seen in the case under study also.
These whitish nodules correspond to the microabscesses which coalesce and extend under the capsule of the affected lymph-node.
Microscopically there is reactive follicular hyperplasiain the earlystages of the disease, followed by the development of the granulomas. There is increase in the macrophage activity, vascular proliferation and increases in monocytoid population of cells [9,10] Present case showed similar features with proliferation of mainly histiocytes and granuloma formation. Cortex of the lymph node characterized by exudation of polymorphonuclear leukocytes with central micro abscessesformation and foci of necrosis.
These abscesses coalesce and form large areas of necrosis, surrounded by neutrophils, band of epithelioid cells palisading and fibrinous material [8,10]. Present case showed focal necrotic areas surrounded by rim of epithelioid cells and also presence of ill-formed granulomas.
B. Henselae is a gram-negative bacterium, but this organism does not readily stain with a Gram stain.
Traditionally, silver impregnation stains such as Warthin-Starry or Steiner stains have been used to aid in the microscopic identification of B. Henselae organisms, which appear as pleomorphic bacilli in clumps or as single forms [10,11,12].
In present case we used GMS stain, bacilli were present within the foci of necrosis and walls of proliferating vessels.

Conclusion
Cat-scratch Disease is a self-limiting illness in an immuno-competent host. The associated lymphadenitis is mainly solitary and unilateral. Identification of Catscratch lymphadenitis would be quite difficult. However, in immune-compromised individuals it might lead to systemic involvement of other organs.
Although it is not a unique diagnosis, precision in labelling it as Cat-scratch disease is required to extract history of animal contacts, proper intervention for diagnosis and implement appropriate and targeted antibiotic therapy.
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