Intense FDG Uptake in Well-Differentiated Inflammatory Liposarcoma of the Retroperitoneum.

ABSTRACT: Inflammatory variant of well-differentiated liposarcoma is a rare subtype of liposarcoma, and its imaging features have been rarely reported. We describe FDG PET/CT findings in a case of well-differentiated inflammatory liposarcoma. The tumor showed no detectable fat and intense FDG uptake and caused diffuse FDG uptake of the bone marrow due to paraneoplastic leukemoid reaction. Microscopically, there were extensive inflammatory infiltrates in the tumor, which may contribute to the intense FDG uptake. This case indicates that although well-differentiated liposarcoma usually shows low-grade FDG uptake, inflammatory variant of well-differentiated liposarcoma can show intense FDG uptake mimicking high-grade liposarcoma.

Juxtaglomerular Cell Tumor Mimicking Renal Cell Carcinoma on 99mTc-MIBI SPECT/CT.

ABSTRACT: Juxtaglomerular cell tumor or reninoma is an extremely rare, typically benign, renin-secreting tumor of the kidney that causes secondary hypertension. We describe 99mTc-MIBI SPECT/CT findings in a case of juxtaglomerular cell tumor. The renal tumor showed isodensity and photopenia on 99mTc-MIBI SPECT/CT. This case indicates that juxtaglomerular cell tumor can appear cold on 99mTc-MIBI SPECT/CT, mimicking renal cell carcinoma.

Intense PSMA Uptake in Solitary Fibrous Tumor of the Seminal Vesicle.

ABSTRACT: Solitary fibrous tumor arising from the seminal vesicle is very rare. We describe 18F-PSMA-1007 PET/CT findings in a case of prostate adenocarcinoma with a solitary fibrous tumor of the left seminal vesicle. The solitary fibrous tumor showed intense 18F-PSMA-1007 uptake mimicking metastatic prostate adenocarcinoma. This case indicates that solitary fibrous tumor may cause false-positive result when using PSMA PET in staging of prostate cancer.

FDG PET/CT in a Case of Isolated Gastric Metastasis From Pancreatic Ductal Adenocarcinoma.

ABSTRACT: Hematogenous gastric metastasis from pancreatic cancer is extremely rare. We describe FDG PET/CT findings in a case of isolated hematogenous gastric metastasis from pancreatic cancer with significantly elevated serum carbohydrate antigen 19-9 level. The gastric metastasis showed intense focal FDG uptake mimicking a primary tumor. The elevation of serum carbohydrate antigen 19-9 level may be useful as an aid in the differential diagnosis.

Hemangioma of the Ilium Simulating Bone Metastasis on 18F-PSMA-1007 PET/CT.

ABSTRACT: A 64-year-old man was referred for 18F-PSMA-1007 PET/CT scan for initial staging of biopsy-proved prostate adenocarcinoma. 18F-PSMA-1007 PET/CT showed focal intense 18F-PSMA-1007 of the prostate adenocarcinoma and a focal intense activity with SUVmax of 10.5 in the left ilium. The 18F-PSMA-1007-avid iliac bone lesion corresponded to a hemangioma, which was initially detected on pelvic MRI 13 months ago and remained stable in size. This case indicates that hemangioma should be included in the differential diagnosis of PSMA-avid iliac bone lesions.

Intense FDG Uptake in Leiomyomatosis Peritonealis Disseminata With Fumarate Hydratase Deficiency.

ABSTRACT: A 35-year-old woman with a history of laparoscopic myomectomy presented with repeated abdominal pain. Contrast-enhanced abdominal and pelvic CT showed multiple enhancing solid or mixed cystic and solid peritoneal masses, and an enhancing uterine mass. All these masses showed intense FDG uptake on FDG PET/CT. The intraperitoneal and uterine masses were surgically removed. The histological and immunohistochemical findings of the peritoneal lesions were consistent with leiomyomatosis peritonealis disseminata with fumarate hydratase deficiency, and the uterine mass was adenomyosis. This case indicates fumarate hydratase-deficient extrauterine leiomyoma can show intense FDG uptake mimicking malignancy.

18 F-FAPI-04 PET/CT in a Case of Primary Gastric Plasmacytoma.

ABSTRACT: Primary plasmacytoma of the stomach is very rare. We describe contrast-enhanced CT and 18 F-FAPI-04 PET/CT findings in a patient with primary gastric plasmacytoma and Helicobacter pylori infection. The gastric tumor appeared as a large hypervascular polypoid mass on contrast-enhanced CT and showed intense 18 F-FAPI-04 uptake with SUV max of 11.8 on 18 F-FAPI-04 PET/CT.

Microcystic Serous Cystadenoma Masquerading as Pancreatic Neuroendocrine Tumor on 99m Tc-HYNIC-TOC SPECT/CT.

ABSTRACT: We present 99m Tc-HYNIC-TOC SPECT/CT findings in a case of microcystic serous cystadenoma of the pancreatic head. The pancreatic tumor showed intense 99m Tc-HYNIC-TOC uptake mimicking neuroendocrine tumor on SPECT/CT. This case indicates that microcystic serous cystadenoma should be included in the differential diagnosis of 99m Tc-HYNIC-TOC-avid pancreatic masses.

FDG PET/CT in Solitary Isolated Renal Metastasis From Squamous Cell Lung Cancer.

ABSTRACT: We describe FDG PET/CT findings in a patient with a solitary isolated renal metastasis from squamous cell lung cancer. The renal metastasis appeared as a small focus of activity at the renal cortex on FDG PET/CT at initial staging of the lung tumor, misinterpreted as cortical tracer retention, and was significantly enlarged on the second FDG PET/CT performed 4 months after the first PET/CT. This case demonstrates the usefulness of FDG PET/CT in identifying unexpected extrathoracic metastasis from lung cancer. Focal FDG uptake in the renal cortical region in a cancer patient should be evaluated carefully to avoid misdiagnosis.

Intense 18 F-PSMA-1007 Uptake of Splenic Hemangioma.

ABSTRACT: A 77-year-old man was referred for 18 F-PSMA-1007 PET/CT scan for initial staging of biopsy-proved prostate adenocarcinoma. 18 F-PSMA-1007 PET/CT showed focal intense 18 F-PSMA-1007 of the prostate adenocarcinoma and a focal intense activity (SUV max , 27) in the spleen. The 18 F-PSMA-1007-avid splenic lesion corresponded to a splenic hemangioma, which was initially detected on contrast-enhanced CT 7 months ago and unchanged in size and enhancement pattern on follow-up contrast-enhanced CT. This case indicates that splenic hemangioma should be included in the differential diagnosis of PSMA-avid splenic lesions.

FDG PET/CT in a Case of Primary Lymphoma of the Ureter.

ABSTRACT: Primary lymphoma of the ureter is extremely rare. We describe the contrast-enhanced CT and FDG PET/CT findings in a case of diffuse large B-cell lymphoma transformed from mucosa-associated lymphoid tissue lymphoma limited to the left ureter. Contrast-enhanced CT showed 2 short-segment circumferential thickening and enhancement of the left pelvic and intramural ureteral wall. The thickened ureteral wall showed significantly increased FDG uptake mimicking urothelial carcinoma.

FDG PET/CT in Pancreatic Ductal Adenocarcinoma Arising From a Heterotopic Pancreas of the Pylorus.

ABSTRACT: Malignant transformation of heterotopic pancreas is extremely rare. We describe FDG PET/CT findings in a case of pancreatic ductal adenocarcinoma arising from a heterotopic pancreas in the submucosa of the pylorus with peripyloric lymph node metastasis and elevated serum carbohydrate antigen 19-9 level. The heterotopic pancreatic adenocarcinoma showed intense FDG uptake, and the peripyloric lymph node metastasis showed mild FDG uptake. This case indicates that heterotopic pancreatic adenocarcinoma should be included in the differential diagnosis of FDG-avid gastric submucosal lesions, especially in patients with elevated serum carbohydrate antigen 19-9 level.

FDG PET/CT in a Case of Thoracic SMARCA4-Deficient Undifferentiated Tumor.

ABSTRACT: Thoracic SMARCA4-deficient undifferentiated tumor is a rare, newly recognized poorly differentiated tumor with poor prognosis. FDG PET/CT findings of thoracic SMARCA4-deficient undifferentiated tumor are rarely reported. We describe FDG PET/CT findings in a case of thoracic SMARCA4-deficient undifferentiated tumor. The tumor presented as a pleural mass, destroyed the adjacent ribs, and showed intense FDG uptake with SUV max of 12.7. This case indicates that thoracic SMARCA4-deficient undifferentiated tumor should be included in the differential diagnosis of FDG-avid pleural lesions.

18 F-PSMA-1007 PET/CT in a Case of Von Hippel-Lindau Syndrome.

ABSTRACT: We describe 18 F-PSMA-1007 PET/CT findings in case of von Hippel-Lindau syndrome with a cerebellar hemangioblastoma, 6 renal cell carcinomas in the bilateral kidneys, cystic lesions in the pancreas and left adrenal gland, and solid lesions in the bilateral epididymides. 18 F-PSMA-1007 PET/CT showed intense activity with SUV max of 111.3 of the cerebellar hemangioblastoma, variable activity with SUV max range of 6.4-37.6 of the renal cell carcinomas, and increased activity of the bilateral epididymal lesions (SUV max of 5.1 and 8.2 for the left and right epididymal lesions, respectively).

Isolated Skull Metastasis With Unusual Spiculated Periosteal Reaction From Rectal Cancer Resembling Osteosarcoma on FDG PET/CT.

ABSTRACT: We describe FDG PET/CT findings in a case of isolated skull metastasis with spiculated periosteal reaction from rectal mucinous adenocarcinoma 8 years after proctectomy. The skull metastasis showed heterogeneous FDG uptake and multiple short spicules of bone producing the sunburst appearance resembling primary osteosarcoma or Ewing sarcoma. Familiarity with this atypical imaging appearance of the bone metastasis from rectal cancer may be helpful for the diagnosis and differential diagnosis.

FDG PET/CT in Follicular Dendritic Cell Sarcoma of the Jejunum With Hepatic Metastasis.

ABSTRACT: Follicular dendritic cell sarcoma of the gastrointestinal tract is a rare malignancy. We describe contrast-enhanced CT and FDG PET/CT findings in a case of jejunal follicular dendritic cell sarcoma with hepatic metastasis. The primary jejunal tumor showed inhomogeneous enhancement on contrast-enhanced CT and intense FDG uptake on PET/CT mimicking adenocarcinoma or gastrointestinal stromal tumor. The hepatic metastatic tumor showed hypovascularity on contrast-enhanced CT and mild FDG uptake on PET/CT. This case indicates that follicular dendritic cell sarcoma should be included in the differential diagnosis of the hypermetabolic intestinal lesions.

68Ga-PSMA-11 PET/CT in a Case of Isolated Parietal Peritoneal Metastasis From Prostate Adenocarcinoma.

ABSTRACT: Isolated peritoneal metastasis of prostate cancer is extremely rare. We present 68Ga-PSMA-11 PET/CT findings in a case of isolated parietal peritoneal metastasis from prostate adenocarcinoma 35 months after radical prostatectomy. The peritoneal metastases showed multifocal intense PSMA uptake, but subtle structural abnormalities on 68Ga-PSMA-11 PET/CT. The patient was subsequently treated with androgen deprivation therapy. The peritoneal metastases progressed 25 months after the initiation of androgen deprivation therapy and were removed surgically. Histologic and immunohistochemical evaluation revealed metastatic prostate adenocarcinoma with treatment-related neuroendocrine differentiation. This case demonstrates the usefulness of 68Ga-PSMA-11 PET/CT in identifying atypical metastasis from prostate adenocarcinoma.

FDG-Avid Malakoplakia of the Ureter Mimicking Malignancy.

ABSTRACT: Malacoplakia is a rare chronic granulomatous disease and frequently associated with Escherichia coli infection. We describe the contrast-enhanced CT and FDG PET/CT findings in a case of bladder and ureteral malakoplakia with E. coli urinary tract infection. Contrast-enhanced CT showed multiple enhancing mural nodules in the bladder and left ureter, ranging from several millimeters to 3.1 cm. The ureteral nodules showed significantly increased FDG uptake with SUVmax of 20.4, due to histiocyte, lymphocyte, and plasma cell infiltrates revealed by histopathology.

99m Tc-MIBI SPECT/CT in a Case of Renal Oncocytosis.

ABSTRACT: Renal oncocytosis is a very rare oncologically indolent form of renal neoplasia characterized by diffuse involvement of renal parenchyma by numerous oncocytic nodules. We describe contrast-enhanced CT and 99m Tc-MIBI SPECT/CT findings in a patient with renal oncocytosis presenting with metachronous bilateral renal tumors. Contrast-enhanced CT showed numerous tumors ranging from several millimeters up to 3.9 cm in the left kidney. The tumors showed hypervascularity in the corticomedullary phase and washout in the excretory phase mimicking renal cell carcinoma. The larger tumors showed higher 99m Tc-MIBI uptake than the adjacent renal parenchyma, suggesting renal oncocytoma confirmed by biopsy.

68 Ga-FAPI-04 PET/MRI in a Case of Tuberous Sclerosis Complex With Extrarenal Retroperitoneal Angiomyolipoma.

ABSTRACT: Extrarenal retroperitoneal angiomyolipomas are rare benign tumors that may mimic other benign or malignant retroperitoneal tumors. We describe 68 Ga-FAPI-04 PET/MRI findings in a case of tuberous sclerosis complex with an extrarenal retroperitoneal angiomyolipoma and multiple angiomyolipomas involving bilateral kidneys. The extrarenal retroperitoneal angiomyolipoma and most of the renal angiomyolipomas were 68 Ga-FAPI-04-avid. One left renal angiomyolipoma with extensive hemorrhage and fibrosis had no significant 68 Ga-FAPI-04 uptake. Angiomyolipoma should be included in the differential diagnosis of FAPI-avid renal or extrarenal retroperitoneal lesions.