Lily Shen

Incidental Prostate-Specific Membrane Antigen Uptake in a Peripheral Nerve Sheath Tumor

A 66-year-old man with recently diagnosed prostate cancer (Gleason score 9) was referred for Ga-prostate-specific membrane antigen (PSMA) PET/CT with prostate-specific antigen level of 7.5 μg/L. PET/CT demonstrated increased PSMA uptake (SUVmax 4.7) in a soft tissue density in the left adductor compartment. MRI and cytopathology of the biopsied soft tissue density was compatible with a peripheral nerve sheath tumor. This case illustrates that PSMA uptake can occur in a peripheral nerve sheath tumor and should be taken into consideration as a benign cause of PSMA uptake.

68Ga-DOTATATE Uptake in Solitary Pancreatic Metastasis From Clear Cell Renal Cancer

A 64-year-old man with a lesion of the pancreatic tail was referred for Ga-DOTATATE PET/CT imaging. His medical history included previous metastatic clear cell renal cell cancer. Ga-DOTATATE PET/CT demonstrated increased DOTATATE uptake (SUVmax 10.5) in a pancreatic tail lesion. Histopathology of the resected lesion confirmed clear renal cell cancer metastasis. This case illustrates that clear cell renal cancer metastasis can demonstrate Ga-DOTATATE accumulation.

Riedel’s Thyroiditis with Intense FDG Uptake Demonstrated on FDG PET/CT

A 39 year old female presented with rapidly enlarging goitre, minimal obstructive symptoms and no constitutional symptoms. Clinical examination revealed diffusely enlarged, firm, non-tender thyroid gland. Biochemical investigations showed subclinical hypothyroidism, positive thyroid antibodies and unremarkable inflammatory markers. Ultrasound examination and CT scan of the neck were suspicious of Riedels thyroiditis. The patient was referred for a FDG PET scan to evaluate for systemic fibro-inflammatory process or lymphoma. Subsequent core biopsy of the thyroid gland demonstrated a chronic inflammatory process with fibrosis consistent with Riedels thyroiditis. A FDG PET/CT study showed diffuse FDG uptake in the thyroid gland and no abnormal retroperitoneal FDG uptake elsewhere to suggest active retroperitoneal fibrosis. The goitre reduced in size with thyroid hormone replacement and steroids, however the patient was lost to follow up.

Demonstration of peritoneo-scrotal communication by Tc-99m MAA scintigraphy following false-negative contrast CT.

Abstract: A 69-year-old man with end stage renal failure was on peritoneal dialysis for 5 months. He developed sudden onset of scrotal swelling after lifting and presented for investigation. Clinically he had bilateral scrotal swelling with findings suggestive of hydrocele. There was no evidence of hernia, peripheral, or dependent edema. CT of the pelvis with peritoneal contrast was performed, and contrast was seen in the dependent areas of the peritoneal cavity but not in the scrotum. Subsequently Tc-99m MAA peritoneal scintigraphy was performed which demonstrated diffuse tracer activity in the scrotum by 4 hours and persisted to 24 hours.

68ga-dotatate Uptake in a Soft Tissue Metastasis From Clear Cell Renal Cell Cancer

A 64-year-old man with a history of metastatic clear cell renal cell cancer was referred for progress Ga-DOTATATE PET/CT imaging. Ga-DOTATATE PET/CT imaging demonstrated increased DOTATATE uptake (SUVmax 13.8) in the left thigh localized to a soft tissue lesion. Cytopathology of the resected lesion was in keeping with a clear cell renal cell cancer metastasis. This case illustrates that Ga-DOTATATE accumulation in a soft tissue lesion can be due to a clear cell renal cell cancer metastasis.

Extrapulmonary Small Cell Carcinoma of the Seminal Vesicles and Prostate Demonstrated on 18F-FDG Positron Emission Tomography/Computed Tomography.

Extrapulmonary primary small cell carcinomas arising from the urogenital tract is infrequent. It can rarely arise from the prostate and even more rarely from the seminal vesicles. We present a 79-year-old male who was admitted due to acute renal failure with a history of radical radiotherapy for prostate adenocarcinoma 13 years ago. The prostate specific antigen level was not elevated. An abdominopelvic computed tomography (CT) scan showed markedly enlarged seminal vesicles causing bilateral ureteral obstruction and a mildly enlarged prostate. Further evaluation with fluorine-18-fluorodeoxyglucose (0F-FDG) positron emission tomography/CT demonstrated extensive 18F-FDG uptake in the pelvis with diffuse involvement of both seminal vesicles and the prostate without pathologic uptake in the lungs or elsewhere in the body. Core biopsies of the prostate and both seminal vesicles revealed diffuse involvement by small cell carcinoma. Therapy could not be instituted due to a rapid deterioration in the patient’s clinical condition.