Value of FDG PET/CT in staging of oral cancer: four simultaneous primary malignancies

Solitary Benign Schwannoma Mimics Residual Malignancy on FDG PET/CT

Schwannomas can be seen in pediatric patients with neurofibromatosis and occur generally in the limbs. Solitary schwannoma rarely occurs in pediatric patients who do not have neurofibromatosis. A 15-year-old girl with Hodgkin lymphoma in the neck underwent follow-up FDG PET/CT scan to monitor the response to the chemotherapy. Although her lesions in the neck were no longer visualized, one focal activity in her left upper back persisted. Excisional biopsy result demonstrated benign schwannoma.

Synchronous quadruple multiple primary cancers of the tongue, bilateral breasts, and kidney in a female patient with a disease-free survival time of more than 5 years: a case report

Background

Reports of synchronous multiple primary cancers in patients with oral cancer have recently been increasing because of progress in radiographic diagnostic techniques. Multiple primary cancers in patients with oral cavity cancer mainly occur in the head and neck region, lung, and esophagus. 2-[18F]-fluoro-2-deoxy-d-glucose positron emission tomography is usually used to identify synchronous multiple primary cancers.

Case presentation

We herein describe a 69-year-old woman diagnosed with synchronous quadruple multiple primary cancers, namely a squamous cell carcinoma of the mobile tongue, invasive ductal carcinoma of the right breast, intraductal carcinoma of the left breast, and chromophobe renal cell carcinoma of the right kidney. We removed the four tumors over three surgical procedures to reduce the surgical risk because the patient had diabetes mellitus. To the best of our knowledge, this combination of multiple primary cancers has not been reported to date. Importantly, we followed this case for 5 years after surgery. The patient was alive and well with no clinical or radiologic signs of recurrent or metastatic disease at the time of this writing.

Conclusions

In the present case, the kidney cancer could not be detected by 2-[18F]-fluoro-2-deoxy-d-glucose positron emission tomography but could be detected by contrast-enhanced computed tomography. To avoid overlooking multiple primary cancers of the kidney, we suggest that contrast-enhanced computed tomography should cover a region extending to the inferior margin of the kidney, rather than only to the liver, in patients with oral cavity cancer.