A rare gynecological case of paraneoplastic cerebellar degeneration discovered by FDG-PET

BACKGROUND

PET/CT may be particularly useful to detect the primary cancer in paraneoplastic cerebellar degeneration (PCD) with anti-Yo which is most commonly associated with breast, ovarian and other gynecological cancers.

CASE

A 60-year-old woman developed a PCD associated with anti-Yo antibodies in serum and cerebrospinal fluid. Conventional imaging was negative. FDG-PET showed an abnormal hot spot in the right ovarian area associated with lombo aortic lymph nodes. The diagnosis was confirmed by surgery as an ovarian adenocarcinoma.

CONCLUSION

In this case report, FDG-PET played a crucial role in detecting the unknown primary tumor in a patient with PCD.

Evaluation of FDG PET in early axillary lymph node response to neoadjuvant chemotherapy in locally advanced breast cancer patients

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Background: Regional axillary lymph node status has remained the single most independent variable to predict prognosis both in terms of disease recurrence and survival. This study aimed to prospectively assess sequential FDG PET findings as early predictors of axillary lymph node response to neoadjuvant chemotherapy in locally advanced breast cancer patients. Methods: A total of 255 attenuation-corrected scans were obtained from 51 patients. Images were acquired with a PET/CT scanner (GE Discovery LS) following administration of FDG (5 MBq/kg) at baseline, and after the first, second, third, and sixth course of chemotherapy. Clinical examination and US were used to assess the size of axillary lymph nodes. PET data were interpreted using standardized uptake values (SUV) corrected or not for partial volume effects. Changes in the SUV were considered as surgical/histopathological responses. Results: This study focused on axillary lymph node staging, therefore, primary breast tumor data were not considered in the analysis. The sensitivity, specificity, and accuracy of axillary node staging was higher with PET (75%, 87%, 80%) than with clinical examination and US (50%, 78%, 63%, and 50%, 83%, and 65%, respectively), and even the more so when PET images were corrected for partial volume effects (86%, 83%, 84%). Significant differences between absolute FDG uptake values in responders and non-responders were observed at baseline (p < 0.05). While FDG uptake did not vary much in non-reponders, as confirmed by histopathology, it markedly decreased to baseline levels in responders (p < 10−5). Fifty percent of baseline SUV was considered the best cut-off value to distinguish responders from non-responders. The sensitivity, specificity, negative predictive value, and accuracy of FDG PET after one course of chemotherapy were respectively, 96%, 75%, 95%, and 84%. Tumor response assessment by clinical examination or US was never statistically significant whatever the cut-off. Conclusions: The pathological status of regional axillary lymph nodes in locally advanced breast cancer patients can be accurately predicted after one course of neoadjuvant chemotherapy based on FDG PET images.

No significant financial relationships to disclose.

Brown fat in breast cancer patients: analysis of serial 18F-FDG PET/CT scans

PURPOSE

It has recently been suggested that FDG accumulation in the brown adipose tissue varies as a function of age, sex and outdoor temperature. The aim of this study was to assess changes in FDG uptake in brown fat in patients based on serial PET/CT scans and to compare our results with previous findings.

METHODS

Early response to neoadjuvant chemotherapy in 33 female breast cancer patients was assessed by FDG PET. Five PET/CT scans were performed for each patient. PET/CT images were analysed retrospectively. PET scans were considered positive when diffuse, symmetrical, abnormal "USA" (uptake in supraclavicular area) fat was detected.

RESULTS

A total of 163 PET images were analysed. Seventy-four PET scans (45%) revealed abnormal FDG uptake in the supraclavicular area. These foci were present on uncorrected and attenuation-corrected images. FDG uptake was identical on all five scans in only five patients. No significant relationship was found between abnormal FDG uptake and outdoor temperature, age or time interval between chemotherapy and PET. Abnormal FDG uptake in the neck seemed to predominantly occur in patients with a low body mass index (p<0.05). Most significant changes in the PET/CT scan results were observed during chemotherapy with docetaxel (p<0.05). When observed, bilateral uptake in the neck was more intense than background uptake (p<0.00001).

CONCLUSION

This study shows that FDG uptake in the neck varies as a function of time, that it is unrelated to age or outdoor temperature, and that bilateral uptake is generally intense.

The Impact of Nonvisualization of Sentinel Nodes on Lymphoscintigraphy in Breast Cancer

BACKGROUND

This study aimed at evaluating the relationship between the nonvisualization of sentinel nodes (SNs) at lymphoscintigraphy and the intraoperative detection rate, radioactive counts in vivo, and histological status of SNs.

METHODS

Two hundred eighty patients with infiltrating breast carcinoma (T0, T(1)/T(2)) underwent preoperative lymphoscintigraphy before gamma probe-guided SN biopsy.

RESULTS

The surgical identification rate with a gamma probe was 84.6% (56 of 280) in lymphoscintigraphy-negative patients and 93.2% (224 of 280) in lymphoscintigraphy-positive patients (P < .05) after two subdermal periareolar injections. The average number of SNs per patient was 1.7 in lymphoscintigraphy-negative patients and 2.2 in lymphoscintigraphy-positive patients (P < .01), as assessed by gamma detection. The mean age of lymphoscintigraphy-negative patients was 62 +/- 10 years, versus 55 +/- 13 years for lymphoscintigraphy-positive patients (P < .001). The median radioactive count in dissected SNs identified by gamma detection was 204 cps (range, 4-618 cps) in lymphoscintigraphy-negative patients, versus 606 cps (range, 43-16,928 cps) in lymphoscintigraphy-positive patients (P < .001). The rate of macrometastatic SNs was 40% in lymphoscintigraphy-negative patients, versus 30% in lymphoscintigraphy-positive patients (not significant), whereas the size of involved SNs was 16.6 mm in lymphoscintigraphy-negative patients, versus 13.1 in lymphoscintigraphy-positive patients (P < .05). The micrometastasis detection rate in SNs from lymphoscintigraphy-negative patients was 6.25%, versus 23.3% in lymphoscintigraphy-positive patients (P < .01).

CONCLUSIONS

Negative lymphoscintigraphy was observed in 20% of patients and was more frequent in elderly patients. Negative lymphoscintigraphy was predictive of a lower surgical identification rate and fewer detected SNs. These SNs had fewer micrometastases, were fairly large, and tended to harbor metastases.

Interest of F-18 fluorodeoxyglucose positron emission tomography in the evaluation of vaginal malignant melanoma

BACKGROUND

This is the first report of FDG-PET findings in a case of vaginal melanoma.

CASE

The tumor arose from the anterior wall of the vaginal canal. As the tumor was limited to the vaginal wall and as there was no evidence of distant metastases, the disease was staged as IIC (AJCC 2002). PET-CT images showed two mediastinal foci localized to the left highest mediastinal and subcarinal nodes on fusion PET/CT images. As it was metastatic, the disease was staged IV (AJCC 2002).

CONCLUSION

In comparison to conventional imaging, FDG-PET provides a more accurate assessment of the extent of disease spread in patients with vaginal melanoma as with cutaneous melanoma. Significant alterations in the surgical management and treatment were made based on PET results.

Post-synchronized scintigraphic data to estimate antral motility

We evaluated an improved dynamic antral scintigraphy (DAS) technique, without any frequency filtering or computation of an autocorrelation function. This DAS was performed in 15 consecutive patients and 10 healthy volunteers. Antral frequency was first estimated and was given as an input parameter to compute phase and amplitude values in each antral pixel. Motility indices were calculated by multiplying the frequency by a normalized amplitude in the whole antrum. In addition, a gastric emptying (GE) test was performed. Only 10 patients had a delayed GE when using a cut-off value of the mean of half emptying time (T +2SD) obtained in controls. Antral frequencies were significantly increased but motility indices were significantly lower in patients than in controls. These results in patients were accounted for by a retention of food in the antrum. Therefore, amplitude normalization by the antral mean count activity of each set of data was essential for discriminating between patients and controls and normalized indices appeared early predictors of hypomotility in patients with normal GE. This improved DAS technique should be a useful tool to assess antral dysmotility noninvasively, and may be of physiological and clinical interest.

[Cutaneous metastases from follicular thyroid cancer]

BACKGROUND

Cutaneous metastases from differentiated thyroid carcinoma are rare: only 41 cases have been reported in the literature.

CASE REPORT

A 57-year-old woman underwent total thyroidectomy for a poor differentiated follicular thyroid carcinoma, with involvement of sternum and pulmonary metastases. Despite iodine-131 ablative therapy (> 1 Ci) she developed a skin metastasis of the scalp 9 years after the initial surgery. She died of widely metastatic thyroid carcinoma.

DISCUSSION

Follicular carcinoma has a greater preponderance than papillary carcinoma for cutaneous metastases. The majority of skin metastases are localized to the head and neck. The development of a cutaneous metastasis is commonly associated with metastasis to other distant tissues and is followed by a deteriorating course and eventual death resulting from malignancy.

Gastric emptying of solids: estimates of lag phase and constant emptying times

There is no consensus regarding the best way to estimate the lag phase time (Tlag) and the constant emptying time (TRE) of the gastric emptying of solids. Furthermore, biphasic gastric emptying is usually described by the modified power exponential function of either Elashoff or Siegel. In an attempt to test the validity of the power exponential functions and to identify relevant parameters of biphasic gastric emptying, we followed an approach which consists of describing the power exponential function by two straight lines. The first line is horizontal and represents Tlag. The second line is tangential to the constant emptying [tangent at the maximum slope (MS) or at the half-emptying value]. Scintigraphic data of 132 patients and 15 controls were fitted by both power exponential functions. Each corresponding half-emptying time, Tlag and TRE estimated from the Elashof and Siegel power exponential functions were strongly correlated (0.93 < r < 1, P < 0.0001). The Bland and Altman statistical method demonstrated good agreement (<5% outliers). The half-emptying tangent method sometimes gave negative Tlag and should be abandoned. Tlag(MS) and TRE(MS) did not correlate and therefore were independent parameters. We conclude that the Elashoff and Siegel functions are equivalent and that the maximum slope tangent method allows a reliable description of the two independent phases of gastric emptying.