University of Central Florida College of Medicine Orlando, FL
Richard Henriquez, MD1, Irene T. Riestra Guiance, MD1, Yu Y. Nway, MD2, Ernesto Robalino Gonzaga, MD1, Lakhinder Bhatia, MD2; 1University of Central Florida College of Medicine, Orlando, FL; 2University of Central Florida College of Medicine, Kissimmee, FL
Introduction: The annual incidence of Acute Appendicitis in the United States is approximately 7-10%. Its diagnostic histopathologic findings are presence of neutrophils in the muscularis propria. However, an unusual variant of appendicitis, Acute Eosinophilic Appendicitis (AEA) has eosinophilic infiltration without the presence of neutrophilic infiltration as its pathologic hallmark. This is rarely reported with an incidence of approximately 0.02% worldwide. Therefore, we present a case of acute appendicitis found to have eosinophilic predominance on histology.
Methods: A 47 year old Asian male presented to the emergency department with ongoing right lower quadrant abdominal pain for 3 days. The pain was aggravated by ambulation and palpation and alleviated with oral analgesics. Furthermore, the patient endorsed fevers, anorexia, nausea and decreased bowel movements. He denied any recent travel or exposure to sick contacts. In the emergency department, exam revealed localized right lower quadrant tenderness with a positive Rovsing sign. Lab work showed leukocytosis (13.29, with 68% neutrophils and eosinophilia 4.3). Vitals were significant for tachycardia and temperature of 99.0 F. CT abdomen was consistent for proximal segment appendicular inflammation with severe thickening. With no response to initial conservative management, general surgery was consulted for laparoscopic appendectomy. Histopathology showed eosinophilic infiltrate of the appendix with granulomas and necrotic centers consistent with Eosinophilic Appendicitis. Discussion: Traditionally, the pathognomonic feature of appendicitis on histopathology is predominantly neutrophilic infiltration. However, Acute Eosinophilic Appendicitis (AEA) due to eosinophilic predominance and lack of neutrophils within the appendix causing an inflammatory response is fairly uncommon. The pathogenesis is debated however, the leading theory involves a Type I hypersensitivity reaction. Another association is related to parasitic infections. Accompanying finding of eosinophilia that resolves with appendectomy correlates with AEA (as in our patient). However, if eosinophils remain elevated post appendectomy, eosinophilic gastroenteritis is more likely with possible parasitic infection as a source. This case highlights the histopathologic features of this condition, the only means to confirm the diagnosis. It should also prompt the clinicians to think of underlying mechanism (hypersensitivity vs. infection) and seek appropriate treatment measures.
Histology displaying eosinophils from the appendix after appendectomy
Histology displaying central necrosis and site of Eosinophilic appendicitis
Disclosures: Richard Henriquez indicated no relevant financial relationships. Irene Riestra Guiance indicated no relevant financial relationships. Yu Nway indicated no relevant financial relationships. Ernesto Robalino Gonzaga indicated no relevant financial relationships. Lakhinder Bhatia indicated no relevant financial relationships.