Schwannoma masquerading as metastatic retrocaval lymph node in a patient with incidental gall bladder cancer: a case report and review of literature

Schwannomas are rare benign neoplasms that arise from neural sheath Schwann cells. Their presence in retroperitoneum can mimic other differential diagnosis especially in the setting of a co-existing malignancy. A 31-year-old lady without comorbidities presented with a diagnosis of incidental Gall bladder cancer diagnosed elsewhere. Upon further evaluation, she was found to have a retrocaval mass resembling a metastatic necrotic Lymph node on Contrast Enhanced Computed Tomography (CECT) scan of the abdomen with no evidence of disease elsewhere. Due to the unusual location, mass was biopsied which was inconclusive. Surgical excision of the same was done during Revision cholecystectomy and Final histopathology report revealed it to be a benign Schwannoma. Retroperitoneal Schwannoma with degenerative changes can be a great mimicker of metastatic necrotic malignant lymph node and create diagnostic confusion. With prompt suspicion in mind and clinicoradiological correlation, it is imperative to make informed surgical decisions to avoid erroneous diagnoses that could lead to over treatment. This case underscores the importance of being aware of the differential diagnoses and the need for proper surgical resection of schwannomas to prevent recurrence and ensure complete treatment. Simultaneously, it emphasizes the importance of not compromising the management of the primary neoplasm, in this case, gallbladder cancer.