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PET/CT for esophageal carcinoma staging detects clinically unsuspected synchronous malignancy
A 74-year-old man with newly diagnosed, biopsy-proven esophageal squamous cell carcinoma of the mid-esophagus underwent initial staging with fluorodeoxyglucose PET/CT examination as part of routine clinical care.
Imaging findings
PET/CT demonstrated intense focal fluorodeoxyglucose (FDG) uptake that corresponded to enlarged lymph nodes in the right neck level II, as well as level III/level IV nodal stations. It also revealed a focal area of prominent hypermetabolic activity at the right tongue base.
The degree of hypermetabolic activity (maximum standardized uptake value [SUVmax], 10.6-13.2) in these lymph nodes was significantly more intense than the activity in the known primary esophageal squamous cell carcinoma (SUVmax, 3.3).
Further, an intensely hypermetabolic focus in the right paramedian tongue base (SUVmax, 10.4) was highly suspicious for a synchronous head and neck malignancy.
The patient subsequently underwent ultrasound-guided fine-needle aspiration biopsy of the right neck level II and level III/level IV lymph nodes.
The cytology demonstrated dissociated and occasional clusters of atypical squamous cells, consistent with a metastatic keratinizing squamous cell carcinoma.
Discussion
The patient was referred for staging FDG PET/CT imaging of his known esophageal squamous cell cancer.
In addition to metastatic lymphadenopathy that was in the region somewhat atypical for esophageal carcinoma metastases, a prominent hypermetabolic focus in the right tongue base also was detected, and it was highly suspicious for a synchronous malignancy.
The patient was both a heavy drinker and a smoker. Both significantly increased his risk for head and neck cancer, specifically squamous cell carcinoma of the oral cavity.
Editor’s note: Each figure is in transaxial orientation, with PET images in the top left, CT images in the top right and bottom left, and fused PET and CT images in the bottom right.
Images courtesy of M. Ghesani, MD reprinted with permission.
This case highlights the concept of “field cancerization,” meaning external factors transform existing precancerous lesions into a cancer, resulting in multifocal or multiple synchronous malignancies.
In our case, the degree of FDG uptake (SUVmax) in the right neck lymphadenopathy was significantly higher than in the patient’s known esophageal neoplasm. This suggested the right neck lymph nodes to more likely be metastatic from his incidentally detected, markedly hypermetabolic tongue lesion.
Additionally, the pathology results of the right neck nodal aspirate were positive for keratinizing squamous cell carcinoma, which further corroborated our initial hypothesis based on the imaging findings.
FDG PET/CT is used for accurate staging and restaging of head and neck squamous cell cancer. It is more sensitive and specific than CT or MRI alone in the assessment and follow-up of head and neck malignancy.
However, it is important to remember that normal structures in the head and neck region — including the nasal turbinates, major and minor salivary glands, oropharyngeal musculature and lymphatic tissue in the Waldeyer ring — may demonstrate variable FDG uptake that is asymmetric, often leading to false-positive results.
In addition, variations in the normal mucosal uptake, salivary contamination and inflammatory lesions also can lead to focal FDG uptake in the head and neck. Therefore, multiple biopsies may be necessary to detect malignancies in this region.
Squamous cell carcinoma of the oral cavity is most frequently located in the ventrolateral aspect of the mid- and posterior tongue due to accumulation of carcinogens in this area.
Although this location has the advantage of being easily inspected on clinical exam, patients typically present rather late in the disease course, with nodal metastases in half of patients at the time of diagnosis. Therefore, cervical lymphadenopathy — or neck mass — may be the initial presenting clinical symptom.
In our case, the patient’s FDG PET/CT findings were confirmed by pathology results that were consistent with metastatic keratinizing squamous cell carcinoma, typical for a head and neck primary neoplasm.
The patient subsequently underwent laryngoscopy and directed biopsies of the base of the tongue and the results were consistent with primary squamous cell carcinoma of the tongue.
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For more information:
Munir Ghesani, MD, FACNM, is assistant professor of radiology and director of PET/CT fellowship at NYU Langone Medical Center in New York. He also is a HemOnc Today Editorial Board member. He can be reached at munir.ghesani@nyumc.org.
Ana M. Franceschi, MD, is a senior radiology resident at NYU Langone Medical Center.
Disclosure: Ghesani and Franceschi report no relevant financial disclosures.