Objective The aim of this report is to highlight the value of excision when treating and diagnosing endometriosis, as well as present an unusual case of concomitant endometriosis and pelvic malignancy in a young female. Case Report In a university hospital referral center, a 24-year-old nulligravid woman with suspected endometriosis had been treated unsuccessfully with empiric therapy for several years. Interventions were preoperative cyclic and continuous combined oral contraceptive pills and a NuvaRing for 2 years. Diagnosis was completed by laparoscopy and histologic evaluation. Surgical debulking by gynecology oncologist was followed by chemotherapy. The main outcome measure was definitive diagnosis via histology. Results Histologic diagnosis of endometriosis and concomitant pelvic malignancy with successful surgical excision of both. Conclusions When evaluating a patient with chronic pelvic pain, it is necessary to have a high degree of suspicion for endometriosis. Early surgical and histologic evaluation is imperative for definitive diagnosis. An added benefit of histologic diagnosis is the opportunity to assess for malignancy.