Castleman disease is a rare condition with variable forms of clinical presentation. Diagnosis is therefore difficult and the ideal management of the disease has yet to be defined. Prognosis varies as a function of histologic type. Treatment can range from curative surgery for the unicentric form of the disease to a combination of treatments for the multicentric form. This paper describes an unusual case of unicentric Castleman disease in which the differential diagnosis included several gynaecological malignancies. The lesion was resected, with histopathology and immunohistochemistry confirming the diagnosis. The surgical procedure was completed without complications and follow-up of the patient over one year has shown no signs of recurrence. A literature review was performed, and the possible conditions to be included within the differential diagnoses are discussed.