Retroperitoneal Pelvic Solitary Fibrous Tumor With High Tracer Uptake in 68Ga-DOTATOC PET/CT: A Rare Differential Diagnosis of Paraganglioma

68 Ga-DOTATOC PET/CT Imaging of a Muscular Solitary Fibrous Tumor

ABSTRACT

A 73-year-old woman was referred for 68 Ga-DOTATOC PET/CT staging of a grade 2 pancreatic neuroendocrine tumor, which showed the primary pancreatic tumor, liver metastases, one left pleural metastasis, and high uptake in a mass of the right triceps brachii muscle. Two years before, she underwent 18 F-FDG PET/CT and 111 In-pentetreotide scan, respectively, with low and high uptake of each radiotracer in the triceps mass. Histopathological analysis revealed a solitary fibrous tumor. Immunohistochemistry showed no staining for SSTR-2 and SSTR-5, suggesting tumor overexpression of another somatostatin receptor. This case highlighted a potential pitfall on 68 Ga-DOTATOC PET/CT.

Abdominopelvic Hemangiopericytoma Mimicking Neuroendocrine Tumor on 68 Ga-DOTANOC PET/CT

ABSTRACT

We present the case of a 60-year-old man who was being evaluated for 2 intra-abdominal masses. The masses were tracer avid on 68 Ga-DOTANOC PET/CT and were suggestive of neuroendocrine tumor. Histopathology, however, confirmed the masses to be hemangiopericytoma. Hemangiopericytoma comes under the umbrella of solitary fibrous tumors, a rare tumor group arising from the mesenchymal cells. Solitary fibrous tumors commonly arise from the pleura but can occur anywhere in the body. Intra-abdominal hemangiopericytoma are extremely rare and should be kept in mind as one of the differential diagnoses for 68 Ga-DOTA peptide-avid tumors.

Incidental Finding of a Parotid Basal Cell Adenoma With High Tracer Uptake on 68Ga-DOTATOC PET/CT

ABSTRACT

A 67-year-old man was referred to our department to undergo a 68Ga-DOTATOC PET/CT during the systematic follow-up of a small intestine neuroendocrine tumor. PET revealed an incidental focal increased uptake of 68Ga-DOTATOC matching with a left intraparotid lesion on the combined contrast-enhanced CT, suggestive of a benign salivary tumor. An MRI was performed to characterize this lesion, and finally, the patient underwent surgery. Histological analysis confirmed the presence of a basal cell adenoma.

Isolated Metastasis to Spleen-Stomach Space From Follicular Thyroid Cancer Combined With a Benign Subcutaneous Nodule on 18F-FDG PET/CT and 131I Scintigraphy

ABSTRACT

A 40-year-old woman with follicular thyroid cancer underwent a systemic PET/CT evaluation before operation and then received total thyroidectomy and radioactive 131I ablation therapy. Posttreatment imaging of 131I whole-body scan with SPECT/CT showed that metastasis on the spleen-stomach space coexists with mimicking subcutaneous metastasis, considering their level of 131I accumulation and morphological changes on PET/CT. However, histopathology confirmed the subcutaneous lesion of fibrous hyperplasia by fine-needle aspiration. This case demonstrates a vital role of SPECT/CT in the diagnosis of metastatic thyroid cancer and mimicking metastasis.