Faculty Bibliography

PURPOSE: To retrospectively assess the utility of whole-lesion apparent diffusion coefficient (ADC) metrics in characterizing the Gleason 4 component of Gleason 7 prostate cancer (PCa) at radical prostatectomy. MATERIALS AND METHODS: Seventy patients underwent phased-array coil 3T-magnetic resonance imaging (MRI) before prostatectomy. A uropathologist mapped locations and Gleason 4 percentage (G4%) of Gleason 7 tumors. Two radiologists independently reviewed ADC maps, aware of tumor locations but not G4%, and placed a volume-of-interest (VOI) on all slices including each lesion on the ADC map to obtain whole-lesion mean ADC and ADC entropy. Entropy reflects textural variation and increases with greater macroscopic heterogeneity. Performance for characterizing Gleason 7 tumors was assessed with mixed-model analysis of variance (ANOVA) and logistic regression. RESULTS: Among 84 Gleason 7 tumors (G4% 5%-85%, median 30%; 59 Gleason 3+4, 25 Gleason 4+3), ADC entropy was significantly higher in Gleason 4+3 than Gleason 3+4 tumors (R1: 5.27 +/- 0.61 vs. 4.62 +/- 0.78, P = 0.001; R2: 5.91 +/- 0.32 vs. 5.57 +/- 0.56, P = 0.004); mean ADC was not significantly different between these groups (R1: 0.90 +/- 0.15*10-3 cm2 /s vs. 0.98 +/- 0.21*10-3 cm2 /s, P = 0.075; R2: 1.06 +/- 0.19*10-3 cm2 /s vs. 1.14 +/- 0.16*10-3 cm2 /s, P = 0.083). The area under the receiver operating characteristic (ROC) curve (AUC) for differentiating groups was significantly higher with ADC entropy than mean ADC for one observer (R1: 0.74 vs. 0.57, P = 0.027; R2: 0.69 vs. 0.61, P = 0.329). For R1, correlation with G4% was moderate for ADC entropy (r = 0.45) and weak for mean ADC (r = -0.25). For R2, correlation with G4% was moderate for ADC entropy (r = 0.41) and mean ADC (r = -0.32). For both readers, ADC entropy (P = 0.028-0.003), but not mean ADC (P = 0.384-0.854), was a significant independent predictor of G4%. CONCLUSION: Whole-lesion ADC entropy outperformed mean ADC in characterizing Gleason 7 tumors and may help refine prognosis for this heterogeneous PCa subset. J. Magn. Reson. Imaging 2014. (c) 2014 Wiley Periodicals, Inc.

PURPOSE: The aim of this study was to determine the diagnostic accuracy of positron emission tomography (PET) in cancer patients undergoing adrenalectomy for presumed metastatic disease, utilizing the gold standard of histopathology. METHODS: We retrospectively reviewed all adrenalectomies for metastatic disease performed at our institution over the last 12 years. Preoperative PET scans were compared with final pathology reports. Statistical analyses were performed with Fisher's exact test for categorical variables and Student's t test for continuous variables. RESULTS: Forty-nine adrenalectomies were performed for metastatic disease. Thirty had preoperative PET imaging and were included in this analysis. Mean age was 65.5 +/- 13.6 years (29-91) and 54 % were male. Mean size was 3.8 cm (0.4-7.1). Primary tumor distribution was 61 % (n = 17) pulmonary; 11 % (n = 3) breast; 7 % (n = 2) gastric; 7 % (n = 2) renal; and 4 % (n = 1) each of brain, lymphoma, melanoma, and uterine. Mean standardized uptake value (SUV) was 11 +/- 7.3 (3.2-30.0). Final pathology revealed that 80 % (25/30) were positive for metastatic disease and 20 % (5/30) were negative. The positive predictive value of PET in correctly identifying adrenal metastatic disease was 83 % (24 true-positive cases and 5 false-positive cases); there was one false-negative PET. False-positive PET results were not correlated with sex (p = 0.35), age (p = 0.24), or maximum SUV units (p = 0.26). CONCLUSIONS: The 20 % false-positive rate for PET-positive adrenalectomies performed for metastatic disease should warrant its inclusion in preoperative counseling to the patient and interaction with the treating oncologist.

PURPOSE: To report design of a simplified external transmit-receive coil array for 7 Tesla (T) prostate MRI, including demonstration of the array for tumor localization using T2-weighted imaging (T2WI) at 7T before prostatectomy. MATERIALS AND METHODS: Following simulations of transmitter designs not requiring parallel transmission or radiofrequency-shimming, a coil array was constructed using loop elements, with anterior and posterior rows comprising one transmit-receive element and three receive-only elements. This coil structure was optimized using a whole-body phantom. In vivo sequence optimization was performed to optimize achieved flip angle (FA) and signal to noise ratio (SNR) in prostate. The system was evaluated in a healthy volunteer at 3T and 7T. The 7T T2WI was performed in two prostate cancer patients before prostatectomy, and localization of dominant tumors was subjectively compared with histopathological findings. Image quality was compared between 3T and 7T in these patients. RESULTS: Simulations of the B1 + field in prostate using two-loop design showed good magnitude (B1 + of 0.245 A/m/w1/2 ) and uniformity (nonuniformity [SD/mean] of 10.4%). In the volunteer, 90 degrees FA was achieved in prostate using 225 v 1 ms hard-pulse (indicating good efficiency), FA maps confirmed good uniformity (14.1% nonuniformity), and SNR maps showed SNR gain of 2.1 at 7T versus 3T. In patients, 7T T2WI showed excellent visual correspondence with prostatectomy findings. 7T images demonstrated higher estimated SNR (eSNR) in benign peripheral zone (PZ) and tumor compared with 3T, but lower eSNR in fat and slight decreases in tumor-to-PZ contrast and PZ-homogeneity. CONCLUSION: We have demonstrated feasibility of a simplified external coil array for high-resolution T2-weighted prostate MRI at 7T.J. Magn. Reson. Imaging 2013. (c) 2013 Wiley Periodicals, Inc.

Background Parathyromatosis, described as hyperfunctioning, benign parathyroid tissue scattered throughout the soft tissues of the neck, is a rare cause of recurrent hyperparathyroidism. Fewer than 40 cases have been described in the literature. We describe a case of a woman with recurrent hypercalcemia secondary to parathyromatosis; additionally this is the first reported case of a papillary pattern in parathyromatosis. Clinical Case A 45 year old woman with a history of a left parathyroid adenoma, status post focused parathyroidectomy 10 years ago, presented with constipation, polyuria and abdominal pain. Initial examination demonstrated a well healed cervical scar with no palpable neck masses. Admission laboratory findings were significant for a calcium level of 13.6 mg/dL (n 8-10.4 mg/dL) , ionized calcium 7.7 mg/dL (n 4.6-5.2 mg/dL), phosphorus 2.2 mg/dL (n 2.7-4.5 mg/dL), 25 OH-vitamin D 9.6 ng/mL (n 30-100 ng/mL), PTH 395 pg/mL (n 14-72 pg/mL), PTHrP <0.7 pmol/L (n <2.0 pmol/L) and urine calcium 484 mg/24 hr (n 50-250 mg/24hr). No obvious enlarged parathyroid was localized on neck ultrasound or sestamibi scan. Neck CT showed two 6 mm nodular lesions in the upper mediastinum. The patient had refractory hypercalcemia despite maximal medical therapy. She was taken to the operating room for reoperative neck exploration. She was noted to have diffuse exophytic fronds of tissue covering her left thyroid lobe, which prompted removal of the lobe. Intraoperative PTH decreased from 454 pg/mL to 39 pg/mL. Microsopic examination demonstrated multifocal hypercellular parathyroid nodules in skeletal muscle and perithyroid adipose tissue consistent with parathyromatosis. An unusual pathologic finding was its unique papillary configuration, raising consideration for a parathyroid carcinoma on frozen section. Final pathology confirmed parathyromatosis with no features of carcinoma (vascular invasion, fibrosis or high mitotic activity) with diffuse immunohistochemical reactivity for PTH and non-reactivity for Thyroid Transcription Factor-1. The patient's calcium level was normal post operatively (9.2 mg/dL) with resolution of symptoms. Conclusion Parathyromatosis is a rare disease that raises challenges in diagnosis and management. Preoperative localization of parathyromatosis is difficult, leading to a high surgical failure rate. Scarring and fibrosis from previous neck exploration leads to technical difficulty, since the most common cause for parathyromatosis is seeding of hypercellular parathyroid tissue during previous parathyroidectomy. Medical management is essential during the post-operative period to maintain a normocalcemic state. Our case presents with a pathologic finding of papillary pattern in parathyromatosis, which has not been previously described and can pose a diagnostic challenge in separation from papillary carcinoma on frozen section examination

Retroperitoneal schwannoma is a rare tumor that is often misdiagnosed as malignancy due to a concerning appearance on cross-sectional imaging. Pathology and immunohistochemistry form the gold standard for diagnosis; as such, local excision is the treatment of choice for this disease. We present two cases of juxta-adrenal ancient schwannoma that were treated with adrenalectomy and discuss the current literature regarding this entity.

Clear cell sarcoma of the penis is exceedingly rare with only one prior case involving the penis reported in the literature. We present the case of a 32 year old male who presented with an infiltrative neoplasm at the base of the penis as well as extensive metastatic disease to the lymph nodes and bone. Morphologic, immunohistochemical and cytogenetic findings established the diagnosis of clear cell sarcoma. Despite chemotherapy the patient's disease was rapidly progressive and the patient died of disease within 8 months of diagnosis.