The patient had no history of arterial intervention or IVDU (most common cause of mycotic aneurysm at this site). He went on to have arterial reconstruction. 

Histology

MICROSCOPIC DESCRIPTION:

Sections of the lymph node show atrophy with dropout of lymphoid follicles, being replaced by fibrosis and fat. The remaining lymphoid follicles are mostly primary in type. Very occasional secondary follicles with small germinal centers are noted. The lymphoid cells appear uniform, though they are small in size with no nuclear atypia. The interfollicular zone contains increased numbers of plasma cells, along with some neutrophils. No Dutcher bodies are noted. There is normal distribution of B and T-lymphocytes. The CD23+ follicular dendritic cell network is intact. The kappa and lambda CISH shows no evidence of light chain restriction. No increased numbers of IgG4 cells are seen. The spirochaete immunostain is negative. There is no evidence of lymphoma. 2. Sections of the artery show marked intimal and medial hypertrophy with fibrosis and dystrophic calcification. Some parts of the vessel wall are disrupted and attenuated. There is abundant surrounding inflammatory exudate with fibrin and neutrophils. No granulomas are seen. The Gram stain shows many clumps of Gram positive bacterial cocci. The Grocott stain shows no fungi.

DIAGNOSIS:

1. Lymph node: Fibrosed and atrophic lymph node with active chronic inflammation. No evidence of malignancy.
2. Left femoral artery wall: Disruption with acute inflammation and bacteria, consistent with an infection.