18F-FDG PET evaluation of sinonasal papilloma

The Role of Positron Emission Tomography for the Management of Sinonasal Malignancies: A Systematic Review

BACKGROUND

Positron emission tomography (PET) scan is a valuable imaging modality widely used in the management of cancers. Its usage is well defined for most head and neck malignancies. However, there is a lack of consensus regarding the utility of PET scan for sinonasal malignancies. This is highlighted by the latest international consensus statement on endoscopic skull base surgery.

OBJECTIVE

This systematic review aims to clarify the role of PET scan in the management of sinonasal malignancies.

METHODS

We conducted a comprehensive literature search using PubMed, MEDLINE, EMBASE, Web of Science, CINAHL, and Cochrane databases for research studies of interest. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) updated statement was used to guide the review.

RESULTS

In total, 1807 articles were assessed for eligibility. Thirty-nine original papers, published between 2004 and 2021, met inclusion criteria. Seven articles focused on the role of PET scan for inverted papilloma, 23 for sinonasal carcinoma, 4 for melanoma, and 3 for lymphoma, and finally, 3 articles focused on the use of specific PET scan tracers for sinonasal malignancies. Qualitative summaries for each potential role of PET scans were provided. In general, included studies were retrospective in nature with low level of evidence.

CONCLUSIONS

In general, and across all types of sinonasal malignancies, PET scan yielded positive results regarding detection and initial staging. It was also considered as the modality of choice for detection of distant metastases, except in the case of sinonasal lymphoma. PET scan's main limit resides in its inability to detect lesions in or close to the metabolic activity of the brain.

PET-CT in Clinical Adult Oncology-V. Head and Neck and Neuro Oncology

Simple Summary

Positron emission tomography (PET), typically combined with computed tomography (CT) has become a critical advanced imaging technique in oncology. With PET-CT, a radioactive molecule (radiotracer) is injected in the bloodstream and localizes to sites of tumor because of specific cellular features of the tumor that accumulate the targeting radiotracer. The CT scan, performed at the same time, provides information to facilitate attenuation correction, so that radioactivity from deep or dense structures can be better visualized, but with head and neck malignancies it is critical to provide correlating detailed anatomic imaging. PET-CT has a variety of applications in oncology, including staging, therapeutic response assessment, restaging, and surveillance. This series of six review articles provides an overview of the value, applications, and imaging and interpretive strategies of PET-CT in the more common adult malignancies. The fifth report in this series provides a review of PET-CT imaging in head and neck and neuro oncology.

Abstract

PET-CT is an advanced imaging modality with many oncologic applications, including staging, assessment of response to therapy, restaging, and longitudinal surveillance for recurrence. The goal of this series of six review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for specific oncologic indications, and the potential pitfalls and nuances that characterize these applications. In addition, key tumor-specific clinical information and representative PET-CT images are provided to outline the role that PET-CT plays in the management of oncology patients. Hundreds of different types of tumors exist, both pediatric and adult. A discussion of the role of FDG PET for all of these is beyond the scope of this review. Rather, this series of articles focuses on the most common adult malignancies that may be encountered in clinical practice. It also focuses on FDA-approved and clinically available radiopharmaceuticals, rather than research tracers or those requiring a local cyclotron. The fifth review article in this series focuses on PET-CT imaging in head and neck tumors, as well as brain tumors. Common normal variants, key anatomic features, and benign mimics of these tumors are reviewed. The goal of this review article is to provide the imaging professional with guidance in the interpretation of PET-CT for the more common head and neck malignancies and neuro oncology, and to inform the referring providers so that they can have realistic expectations of the value and limitations of PET-CT for the specific type of tumor being addressed.

Inverted papilloma originating from the lacrimal sac and the nasolacrimal duct with marked FDG accumulation

Inverted papilloma originating from the lacrimal sac and the nasolacrimal duct is rare, although that in the sinonasal region is a relatively common lesion with local invasion, malignant potential and high recurrence rates after surgery. We report a 52-year-old woman with inverted papilloma of the right lacrimal sac and the nasolacrimal duct, who underwent CT, MR imaging and FDG-PET/CT preoperatively. In addition to CT and MR imaging features similar to those in previous reports, the inverted papilloma exhibited marked FDG accumulation with a maximum standardized uptake value of 7.34 and no other significant FDG accumulation was detected. In summary, our case of inverted papilloma originating from the right lacrimal sac and the nasolacrimal duct noted marked FDG accumulation on PET/CT, which enabled visualization of the localized tumor extension with no metastases.

Management of FDG avid Benign Sinonasal Schneiderian Papilloma: A Case Report and Review of the Literature

BACKGROUND

The inverted and oncocytic subtypes of sinonasal Schneiderian papillomas are benign tumors with possible rare malignant transformation and are typically managed with complete surgical resection and close follow-up. While computed tomography (CT) and magnetic resonance imaging (MRI) are mainstays in preoperative evaluation of bony invasion and soft tissue extension of the lesion, their imaging characteristics by 18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) is less well characterized.

OBJECTIVE

To describe the clinical presentation and management of a PET positive sinonasal lesion. To conduct a literature review of FDG uptake in benign sinonasal papillomas.

METHODS

Case report (n = 1) and literature review of similar cases (n = 32).

RESULTS

We report the case of a 69-year-old man presenting with an isolated left maxillary sinus mass with avid FDG uptake, discovered on PET/CT imaging. An endoscopic left maxillary mega-antrostomy provided successful definitive treatment for final pathologic diagnosis of oncocytic papilloma. Literature review of cases of sinonasal papillomas with avid FDG uptake found that oncocytic papillomas, on average, exhibit greater uptake than inverted papillomas and both may be mistaken as malignancies on PET.

CONCLUSION

While PET imaging demonstrating avid FDG uptake is associated with an increased risk of malignancy, it does not rule out the possibility of a benign sinonasal papilloma nor other benign inflammatory lesions. Particularly, oncocytic papillomas may have very high FDG uptake and mimic malignant lesions.

Clinical Implications of Incidental Sinonasal Positive FDG Uptake on PET-CT

Objectives

Fluorodeoxyglucose positron emission tomography–computed tomography (FDG PET-CT) has been increasingly used in the past decade. Incidental FDG-avid findings are encountered in these studies, several of which with clinical significance. However, the significance of incidental FDG-avid sinonasal findings has not been studied to date.

Study Design

Retrospective cohort study.

Setting

A single tertiary medical center.

Materials and Methods

The medical records were reviewed of patients with incidental sinonasal positive FDG uptake between 2007 and 2016 who referred for further otolaryngological diagnostic workup.

Results

A total of 26 patients were identified, all of whom underwent a diagnostic surgical procedure. Histopathology revealed chronic inflammation (n = 12, 46.1%), malignancy (n = 7, 26.9%), inverted papilloma (n = 4, 15.5%), and fungal infections (n = 3, 11.5%). A unilateral maxillary sinus with FDG uptake was documented for 16 (61.5%) patients. CT evidence of bilateral disease and mucosal or sinus wall thickening correlated with inflammatory disease.

Conclusions

Incidental lesions with positive FDG uptake in the sinonasal cavities are at a high risk (40%) of being neoplastic. A diagnostic biopsy is advocated in these cases.

Relationship between 18FDG-PET and different types of sinonasal malignancies

CONCLUSION

The sensitivity and specificity of a ¹⁸FDG-PET scan may be different according to the histology. The SUV_max and SUV ratio may reflect the tumor's aggressive behavior.

OBJECTIVES

To describe the characteristics of PET/CT scans, including the maximum standard uptake values (SUV_max), at initial diagnosis according to six main types of sinonasal malignancies: sinonasal adenocarcinoma (SNAC), sinonasal undifferentiated carcinoma (SNUC), adenoid cystic carcinoma (ACC), sinonasal malignant melanoma (SMM), olfactory neuroblastoma (ONB), and sinonasal neuroendocrine carcinoma (SNEC).

METHODS

A chart review of 50 patients who were diagnosed and treated for six sinonasal malignancy types over a period of 6 years was conducted. Any ¹⁸F-FDG PET/CT scans for each patient were searched using the hospital's intranet. The SUV_max of the primary sinonasal site was recorded. The liver SUVs were utilized as reference SUVs. The SUV ratio was defined as the ratio of the SUV_max of the primary tumor and the SUV_liver.

RESULTS

The most common malignancy was SNAC (32%), followed by SNUC (24%), ONB (14%), ACC (10%), SMM (10%), and SNEC (10%). The SUV_max and SUV ratio values were significantly different between tumor types (p = 0.002 and 0.012, respectively). SNUC had the highest mean SUV_max (14.2), followed by SNAC (9.9). A similar mean SUV_max was observed for SMM, ONB, and ACC (∼ 7.0). SNEC up-takes the least ¹⁸FDG among these six tumor types (mean SUV_max= 4.7).

Inability of PET/CT to identify a primary sinonasal inverted papilloma with squamous cell carcinoma in a patient with a submandibular lymph node metastasis: A case report

The present study describes the first reported case of a sinonasal inverted papilloma (IP) with squamous cell carcinoma (SCC) that presented as a cancer of unknown primary in the English-language literature. In July 2010, a 66-year old male presented with a 6-month history of a painless, progressive mass in the right submandibular region. Physical examination revealed a 3×4-cm smooth, non-tender mass and subsequently, excision of the right submandibular gland was performed. Post-operative pathological examination indicated poorly-differentiated SCC of the submandibular lymph node. Positron-emission tomography/computed tomography (PET/CT) was unable to identify the primary tumour site in this case, and 14 months later the patient presented with nasal obstruction, leading to the diagnosis of right sinonasal IP with coexistent SCC. The patient received pre-operative radiotherapy, a right total maxillectomy and post-operative radiotherapy. However, the patient succumbed to a distant metastasis 37 months after the initial presentation. ¹⁸F-fluorodeoxyglucose uptake on PET/CT may be not a reliable predictor of malignancy in sinonasal IPs. Therefore, we suggest emphasis of the use of multiple biopsies for suspected sinonasal IPs in order to improve diagnostic accuracy.

Squamous papilloma of the oral cavity and oropharynx on 18F-FDG PET/CT imaging

Squamous papilloma is one of the most common benign neoplasms of the oral cavity and oropharynx. The (18)F-FDG PET/CT metabolic phenotype of this entity has not been described. We document the incidental finding of a hypermetabolic lesion at the right base of the tongue on an FDG PET/CT that proved to be squamous papilloma. The maximum standard uptake value was high at 7.0 g/ml. We conclude that oral cavity squamous papilloma can present with an intensely hypermetabolic phenotype on (18)F- FDG PET/CT. This benign entity should be included in the differential diagnosis of FDG-positive oral and oropharyngeal lesions.