Giant Parathyroid Tumor: Parathyroid Adenoma versus Parathyroid Carcinoma.

Parathyroid adenoma is the most common cause of primary hyperparathyroidism (PHPT). We present the preoperative detection of a giant parathyroid adenoma (GPA) using (99mTc)-sestamibi parathyroid scintigraphy in a patient presenting with severely elevated parathyroid hormone, hypercalcemia, hypophosphatemia, and vitamin D insufficiency. The patient complained of cerebral symptoms and intermittent abdominal discomfort without constipation. After surgical removal of the hyperactive parathyroid gland and D vitamin supplementation, all blood tests were normalized. The clinical and paraclinical characteristics of GPA may raise the suspicion of parathyroid carcinoma, but not absolutely in this case.

Assessment of 68Ga-PSMA-11 PET Accuracy in Localizing Recurrent Prostate Cancer: A Prospective Single-Arm Clinical Trial.

IMPORTANCE: In retrospective studies, 68Ga-PSMA-11 positron emission tomographic (PET) imaging improves detection of biochemically recurrent prostate cancer compared with conventional imaging. OBJECTIVE: To assess 68Ga-PSMA-11 PET accuracy in a prospective multicenter trial. DESIGN, SETTING, AND PARTICIPANTS: In this single-arm prospective trial conducted at University of California, San Francisco and University of California, Los Angeles, 635 patients with biochemically recurrent prostate cancer after prostatectomy (n = 262, 41%), radiation therapy (n = 169, 27%), or both (n = 204, 32%) underwent 68Ga-PSMA-11 PET. Presence of prostate cancer was recorded by 3 blinded readers on a per-patient and per-region base. Lesions were validated by histopathologic analysis and a composite reference standard. MAIN OUTCOMES AND MEASURES: Endpoints were positive predictive value (PPV), detection rate, interreader reproducibility, and safety. RESULTS: A total of 635 men were enrolled with a median age of 69 years (range, 44-95 years). On a per-patient basis, PPV was 0.84 (95% CI, 0.75-0.90) by histopathologic validation (primary endpoint, n = 87) and 0.92 (95% CI, 0.88-0.95) by the composite reference standard (n = 217). 68Ga-PSMA-11 PET localized recurrent prostate cancer in 475 of 635 (75%) patients; detection rates significantly increased with prostate-specific antigen (PSA): 38% for <0.5 ng/mL (n = 136), 57% for 0.5 to <1.0 ng/mL (n = 79), 84% for 1.0 to <2.0 ng/mL (n = 89), 86% for 2.0 to <5.0 ng/mL (n = 158), and 97% for ≥5.0 ng/mL (n = 173, P < .001). Interreader reproducibility was substantial (Fleiss κ, 0.65-0.78). There were no serious adverse events associated with 68Ga-PSMA-11 administration. PET-directed focal therapy alone led to a PSA drop of 50% or more in 31 of 39 (80%) patients. CONCLUSIONS AND RELEVANCE: Using blinded reads and independent lesion validation, we establish high PPV for 68Ga-PSMA-11 PET, detection rate and interreader agreement for localization of recurrent prostate cancer. TRIAL REGISTRATION: ClinicalTrials.gov identifiers: NCT02940262 and NCT03353740.

Bone Flare to Androgen Deprivation Therapy in Metastatic, Hormone-Sensitive Prostate Cancer on 68Ga-Prostate-Specific Membrane Antigen PET/CT.

A 69-year-old man with newly diagnosed prostate cancer PSA 274 ng/mL, Gleason 4+3, T-stage 3b) underwent Ga-PSMA PET/CT for staging with follow-up scans 6 and 13 weeks after androgen deprivation therapy (ADT) initiation. Six weeks after ADT initiation, lymph node metastases observed at staging showed metabolic and radiological regression, whereas the skeleton showed increased PSMA uptake in existing bone metastases and several new PSMA-avid lesions. Skeletal PSMA uptake decreased after 13 weeks of ADT, and prostate-specific antigen decreased to 16 ng/mL. These findings suggest the presence of the flare phenomenon to ADT in bone metastases seen on PSMA PET/CT.