Ga-68 DOTATATE Positron Emission Tomography/Computed Tomography in a Rare Case of Esthesioneuroblastoma

A 51-year-old manpresented with symptoms of nasal blockage and nasal discharge for 1 month. Computed tomography (CT) scan showed a 3.1 cm × 2.5 cm × 1.4 cm sized lesion in the posterior nasal cavity on the right side with extension into sphenoid on the right side with no intracranial extension. He underwent endoscopic excision and was diagnosed to have olfactory neuroblastoma (Hyam's Grade 2). Olfactory neuroblastoma or esthesioneuroblastoma is a rare malignant neoplasm of the nasal cavity and of the paranasal sinus. In treating patients with advanced olfactory neuroblastoma, the combination of craniofacial resection with radiotherapy and/or chemotherapy has significantly improved the survival rate. However, locoregional recurrence and distant metastasis frequently occur, irrespective of the aggressiveness of therapy.[1] Imaging plays a very important role in staging and management of olfactory neuroblastoma, and long-term follow-up is necessary because of the extended interval for recurrent disease.[23] The frequent expression of SSTR2A provides a rationale for radioreceptor diagnosis and therapy with SST analogs in esthesioneuroblastoma.[4] The patient was referred for postoperative evaluation with Ga-68 DOTATATE positron emission tomography (PET)/CT. It [Figure 1a–c] revealed focal uptake just anterior to sphenoid ostium on the right paramedian side, maximum standard uptake value 8.40 with no obvious morphologic lesion, suspicious of residual disease. Magnetic resonance imaging [Figure 2a–c] showed an irregular lesion epicenter at posterosuperior nasal cavity extending to the right sphenoid sinus, which appeared hyperintense on fluid-attenuated inversion recovery and T2 and showed enhancement on postcontrast T1 sequences. He underwent revision nasal endoscopic surgery. Postoperative histopathology [Figure 2d] report was suggestive of olfactory neuroblastoma Grade II. He received adjuvant radiotherapy to face and upper neck with concurrent carboplatin. Follow up Ga-68 DOTATATE PET/CT [Figure 1d–f] after 3 months did not show any abnormal tracer uptake suggestive of resolution of disease. This case emphasizes the role of Ga-68 DOTATATE PET/CT in the management of this rare tumor, especially in residual or recurrent disease where the morphology may have been disturbed due to prior surgery or radiation therapy. Ga-68 DOTATATE PET/CT might be especially useful in regions with difficult tumor visualization resulting from high background, such as brain tissue in 18F fluorodeoxyglucose PET/CT. Somatostatin receptor imaging in patients with esthesioneuroblastoma may facilitate the potential application of radiotheranostic agents for the treatment of this aggressive subtype of tumors.[5]

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Figure 1

Ga 68 DOTATATE positron emission tomography/computed tomography maximum intensity projection image (a) and fused axial image (b) and computed tomography (c) images showing focal radiotracer uptake just anterior to sphenoid ostium on the right paramedian side, maximum standard uptake value 8.40 with no obvious morphologic lesion suspicious of residual disease. Postresurgery and adjuvant radiotherapy Maximum intensity projection image (f) and fused axial image (d) and computed tomography (e) images showing no abnormal tracer accumulation.

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Figure 2

Magnetic resonance imaging showing irregular lesion epicenter at posterosuperior nasal cavity extending into right sphenoid sinus which appears hyperintense on fluid-attenuated inversion recovery (a) and T2 (b) and showing enhancement on postcontrast T1 (c) sequences. Photomicrograph (d) showing small round blue cell tumor in a fibrillary background with occasional mitosis (H and E, ×40). Features are suggestive of olfactory neuroblastoma Grade II

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There are very few reports describing Ga-68-DOTA-peptides PET/CT findings in esthesioneuroblastoma.[6] This eventually opens the avenues for theranostics using Lu-177 DOTATATE in patients with unresectable locally extensive or metastatic esthesioneuroblastoma which is beginning to be explored.[7]