68Ga-PSMA PET/CT versus 18F-FDG PET/CT for detecting lesions in a case of fumarate hydratase-deficient renal cell carcinoma.

Gallium-68 (68Ga)-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) and fluorine-18-fluorodeoxyglucose(18F-FDG) PET/CT were performed for staging in a 51-year-old man with renal cell carcinoma. Compared with 18F-FDG PET/CT, no obvious tracer uptake in right renal mass and less metastatic lesions were found on 68Ga-PSMA PET/CT. Postoperative pathology demonstrated the diagnosis of fumarate hydratase-deficient renal cell carcinoma (FHRCC).

Radioactive Iodine Therapy Decreases the Recurrence of Intermediate-Risk PTC With Low Thyroglobulin Levels.

CONTEXT: Whether radioactive iodine therapy (RAIT) is necessary for intermediate-risk papillary thyroid cancer (PTC) after total thyroidectomy is still lacking reliable evidence, especially for patients with low postoperative thyroglobulin (Tg) levels. OBJECTIVE: This study conducted a propensity score matching (PSM) analysis to investigate whether RAIT is effective in reducing the recurrence of intermediate-risk PTC with low Tg levels. METHODS: In total, 1487 patients with intermediate-risk PTC with unstimulated Tg ≤ 1 ng/mL or stimulated Tg ≤ 10 ng/mL after total thyroidectomy were enrolled retrospectively. The clinicopathological characteristics were compared between the non-RAIT and RAIT groups before and after PSM (1:4 matching). The impact of RAIT on biochemical recurrence and structural recurrence was evaluated. RESULTS: Overall, 1349 (90.7%) patients underwent RAIT, and 138 (9.3%) did not. After a median follow-up time of 51 months, 30 patients presented with recurrence, including 11 structural and 19 biochemical recurrences. After PSM, the non-RAIT group had a higher rate of structural recurrence (5/138 vs 5/552, P = .046) and biochemical recurrence (6/138 vs 4/552, P = .005) than the RAIT group. Multivariate analysis showed that not receiving RAIT was an independent risk factor for structural recurrence (hazard ratio [HR] 10.572, 95% CI 2.439-45.843, P = .002) and biochemical recurrence (HR 16.568, 95% CI 3.670-74.803, P < .001). Kaplan-Meier analysis showed that the non-RAIT group had more unfavorable recurrence-free survival (structural and biochemical, all P < .05). CONCLUSION: RAIT could decrease the recurrence risk of intermediate-risk PTC in patients with unstimulated Tg ≤ 1 ng/mL or stimulated Tg ≤ 10 ng/mL. Further prospective randomized studies are needed to confirm these findings.

Comparative Study of Initial Post-Therapeutic 131I Single-Photon Emission Computed Tomography/Computed Tomography and Reoperation for the Detection of Residual Lymph Node Metastasis in Patients With Papillary Thyroid Cancer.

OBJECTIVE: To assess the diagnostic performance of initial post-therapeutic 131I single-photon emission computed tomography/computed tomography (SPECT/CT) compared with that of reoperation in detecting residual lymph node metastasis (LNM). METHODS: Patients with iodine-avid LNM detected on the initial post-therapeutic 131I SPECT/CT and who underwent reoperative dissection within 6 months were included. LNMs (numbers and locations) detected via both methods were compared. The American Thyroid Association dynamic risk stratification was performed for patients receiving second radioactive iodine therapy after reoperation. RESULTS: Fifty-three patients with 95 iodine-avid LNMs detected by 131I SPECT/CT were enrolled. Fifty-one (96.2%) patients had 212 LNMs confirmed by reoperation (P = .004). The sensitivity and specificity of 131I SPECT/CT in detecting LNM were 44.8% (95/212) and 91.6% (87/95), respectively. The location frequency of residual LNMs found by 131I SPECT/CT was similar to that of reoperation (P = .057). Thirty-two patients received a second radioactive iodine treatment, and 6 (18.8%) patients still had residual iodine-avid LNM on SPECT/CT. Therapeutic response was evaluated by American Thyroid Association dynamic risk stratification in 16 patients. The number of patients with structural incomplete response, biochemical incomplete response, indeterminate response, and excellent response was 4 (23.5%), 4 (23.5%), 5 (29.4%), and 3 (17.6%), respectively. CONCLUSION: 131I SPECT/CT has high specificity but relatively low sensitivity in detecting all residual LNMs. Approximately 80% of patients were rendered structurally disease free after reoperation.

IgA Nephropathy in a Patient With Metastatic Carcinoma of Unknown Primary: Findings on 18F-FDG PET/MRI.

ABSTRACT: A 35-year-old man with mesenteric metastases of unknown primary was referred for 18F-FDG PET/MRI. The images demonstrated that FDG accumulated in the chest, abdomen, bilateral kidneys, and external genitalia. Renal and testicular metastases were suspected. The primary tumor was still not found. In addition, kidney biopsy findings indicated a diagnosis of IgA nephropathy.