Background: Positron emission tomography (PET)/computed tomography (CT) simulation in cervical cancer may help radiation oncologists to better define the target volumes. It may also detect extrapelvic lesions and incidental second malignancies, leading to significant changes in treatment management. Case: A 63-year-old woman who was deemed inoperable due to carcinoma of the cervical stump extending to the parametria and paraaortic lymph nodes detected on MR images presented for extended field radiotherapy. PET/CT simulation revealed an FDG avid mass in the cervical stump, and an enlarged axillary lymphadenopathy showing moderate FDG uptake. The excisional biopsy was consistent with small lymphocytic lymphoma (SLL). Conclusion: In our case, PET/CT simulation not only led to changes in treatment management, but also revealed a very rare coexistence of SLL and invasive squamous cell carcinoma of the cervix.