A 47-year-old woman presented with a painful, compressible, and mobile lump in the left axilla for three days without discharge or erythema. Prior to lump presentation, the patient had intermittent elbow and arm pain, lasting approximately 45 minutes. She denied fevers, chills, and night sweats. Her family history was significant for a father with liver cancer and maternal grandmother with bone cancer. She worked as a veterinarian and was a former smoker of five pack-years. On physical examination, there was a compressible, mobile, tender lump measuring 30 x 20 mm in the left axilla. Mammogram revealed normal right breast and left axillary lymphadenopathy (Figures , ). The ultrasound showed two adjacent enlarged axillary lymph nodes measuring 31 mm and 27 mm in diameter, respectively (Figure ).\nThe results from the mammogram and ultrasound supported the physical exam findings, prompting further CSD assessment with ultrasound-guided core biopsy. The biopsies showed necrotizing lymphadenitis that partially effaced the lymph node architecture. In the necrotic area, there were microabcesses with neutrophils and surrounding histiocytes, some of which were palisading (Figure ). Giant cells were scattered throughout. Staining for cluster of differentiation 20 and cluster of differentiation 3 showed some residual follicles and interfollicular T cells. Other stains including acid-fast bacilli, methenamine silver stain, toxoplasmosis, and periodic acid-Schiff were all negative. Cat scratch stain was positive. To confirm the diagnosis, serology for B. henselae was subsequently ordered with the results of abnormal B. henselae IgG titer of 1:1024, and abnormal B. henselae antibody IgM titer of 1:32.
A 49-year-old woman presented with arm pain for five days. The pain was located in the right armpit and sensitive to touch. The patient also reported bilateral ear pain. There were no chills, fevers, or night sweats. The patient had a normal screening mammogram five months prior. Her family history was significant for her mother with breast cancer and her father with gastric cancer. Socially, she had two cats. On physical examination, there was a painful mass below the right armpit with no overlying skin lesions. Because of the location of the mass and the family history of breast cancer, a repeat mammogram and an ultrasound were recommended. The imaging results were remarkable for a morphologically abnormal right axillary lymph node measuring 31 mm in diameter (Figure ). Ultrasound-guided biopsy was performed, and the surgical pathology exam results were consistent with cat scratch lymphadenopathy. Flow cytometry revealed no detectable monoclonal B cells or immunophenotypically aberrant T cells, which diminished the concern for malignancy. Serology was not available for this case.