Extraosseous Ewing sarcoma presenting as recurrent intergluteal pilonidal disease

Sewell, Marisa A.; Hulka, Frieda M.; Zucker, Jacob P.

doi:10.1186/s43159-020-00065-5

Extraosseous Ewing sarcoma presenting as recurrent intergluteal pilonidal disease

Authors

Abstract

Background
Pilonidal disease classically presents as an abscess or soft tissue swelling which classically occurs in the intergluteal cleft, just above the anus. Risk factors for this disease include obesity, prolonged sitting, and abundance of gluteal hair. Treatment options are extensive but most often include incision and drainage with antibiotic treatment. Presentation of recurrent intergluteal pilonidal disease in a young, active female would then be unusual. We present a case of a 17-year-old female presenting with what appeared to be intergluteal pilonidal disease. Definitive excision with histopathology revealed a diagnosis of extraosseous Ewing sarcoma.
Case presentation
An otherwise healthy and active 17-year-old female presented to our Pediatric Oncology clinic with a 2-month history of recurrent painful soft tissue swelling of the intergluteal cleft. At that time, she had been diagnosed with pilonidal abscess and had already undergone three incision and drainage procedures. A definitive excision with pathology was performed within weeks of her initial presentation. Immunohistochemical evaluation confirmed a diagnosis of extraosseous Ewing sarcoma.
Conclusion
This unusual case underlies the importance of considering a broad differential when evaluating potential pilonidal abscess in a patient who otherwise has no risk factors. Additionally, definitive excision with pathology is critical in a patient with unusually recurrent disease as this can be crucial in the identification of an alternative, and potentially devastating, diagnosis.

Keywords