CLINICAL HISTORY
A 65-year-old lady presented to the Radiation Oncology clinic with biopsy-proven squamous cell carcinoma of the uterine cervix FIGO IIB. The systemic examination did not reveal any clinically significant lymphadenopathy. Imaging indicated metastatic disease.
Since the FDG avid nodes on the PET CT scan did not follow the anatomical pattern of spread typical for cervical cancer (i.e., no para-aortic nodal enlargement), and some of the PET avid mediastinal nodes were calcified, suspicions arose regarding a second pathology.
The case was discussed with an ENT surgeon, and an excisional biopsy of the posterior cervical chain node was performed. Histopathology revealed chronic granulomatous inflammation suggestive of nodal tuberculosis.
After one week of starting anti-tuberculosis treatment (ATT), she commenced concurrent chemo-radiotherapy (CCRT) with 50 Gy/25 fractions of radiation therapy to the pelvis. Weekly concurrent cisplatin was administered at 40 mg/m2, followed by a 2400 cGy dose of high-dose-rate (HDR) brachytherapy over three fractions using a tandem and ovoids.
IMAGING:
· CT scan of the chest, abdomen, and pelvis raised suspicion of stage IV disease due to mediastinal and neck lymphadenopathy.
· FDG PET CT scan revealed hypermetabolic nodes in the mediastinum measuring 4x4 cm with an SUV max of 8.9. Bilateral neck nodes at levels III–V exhibited an SUV max of 6.6 and measured 2x2 cm. However, on clinical reassessment, the neck nodes were barely palpable (Figure 1).
LEARNING POINTS:
• PET/CT is a valuable investigative tool for cancer staging.
• PET/CT has inherent false positive and false negative rates, particularly in cases of inflammatory lesions like tuberculosis.
• Inflammatory nodes can exhibit high FDG avidity, mimicking cancerous nodes, potentially leading to staging errors. Therefore, it is crucial to critically correlate examination and imaging findings with the pattern of failure. Biopsy and histopathology confirmation becomes essential when nodal spread deviates from the typical patterns of the primary disease.
• Our case emphasizes that tuberculous lymphadenopathy can be highly 18F-FDG avid. Hence, obtaining pathological confirmation is paramount for accurate diagnosis and appropriate management.
• A correct diagnosis upfront is crucial for timely management of both cancer and other potential causes, including infectious ones
Figure 1b: Axial image at level of neck
Figure 1c: Axial image at level of mediastinum showing hyper-metabolic calcified mediastinal nodes.
Figure 1a: Coronal image of PET CT showing
hyper-metabolic neck and mediastinal nodes
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