18F-FDG PET/CT in lung B lymphoid hyperplasia-type Castleman disease.

We present a 62-year-old woman who, after a catarrhal episode, underwent a chest xray and a chest CT, identifying a pleural-based mass in the left lower lobe. This lesion presented a mixed pattern with solid and peripheral ground-glass attenuation, and an air-bronchogram sign. Despite de suspicion of bronchopneumonia, a lung neoplasm like a predominantly lepidic adenocarcinoma could not be ruled. A 18 F-FDG PET/CT showed a focal radiotracer uptake with SUVmax of 5.34 in the pulmonary lesion, supporting the neoplastic etiology. Consequently, a lower lobectomy was performed and histological examination concluded that the final diagnosis was a B lymphoid hyperplasia-type Castleman disease. Castleman's disease is an uncommon disorder that can be easily misdiagnosed as lymphoma, neoplasm or infection. Unicentric Castleman's disease (UCD) usually presents a hyaline-vascular histological subtype and is usually asymptomatic. Extranodal involvement is very rare. Only a few cases of solid organ involvement such us spleen or parotid gland have been described. UCD originating in the lung is extremely rare and should be considered in the differential diagnosis of a primary pulmonary malignant tumor.

Role of 18F-FDG-PET/CT in the management of marginal zone B cell lymphoma.

The use of PET in patients with marginal zone B cell lymphoma (MZL) is controversial because of variability of fluorodeoxyglucose (FDG) avidity. We analyzed 40 PET/CT in 25 consecutive patients to compare its performance with CT at staging and as a first-line response assessment. Sensitivity of PET/CT and CT was 96 and 76%. Mean standard uptake value was 6.1, 6.9 and 3.4 (p = 0.3) in nodal, extranodal and splenic subtypes, respectively. Of 17 patients (extranodal: n = 9; nodal: n = 6; splenic subtype: n = 2) with both imaging tests available at diagnosis, 8 (47%) had more involved areas with PET/CT than with CT, 75% of which were extranodal lesions. PET/CT resulted in upstaging of five patients although treatment of only two of them was changed. Responses of 15 patients with post-treatment PET/CT were the following: 9 negative and 6 positive of which 3 were isolated residual lesions. Progression was documented in two of these three patients. Response was also assessed by CT in 11 patients. Discrepancies were found in three: Two were in complete remission by CT while PET/CT detected localized residual disease; another patient was in partial remission by CT, whereas PET/CT showed only one positive lesion. Two of these three patients relapsed. Patients with negative post-treatment PET/CT did not relapse. With a median follow-up of 50 months (10-152 months), 3-year overall survival was 100 and 80% for patients with negative and positive post-treatment PET/CT (p = 0.2). Three-year disease-free survival was 86%; the negative predictive value (NPV) was 100%, and the positive predictive value (PPV) was 83.3%. Although a larger number of patients will be required to further confirm these data, we can conclude that PET/CT is a useful imaging tool for both staging and response assessment in patients with nodal and extranodal MZL as a result of its high sensitivity, NPV and PPV.

Contralateral Axillary Lymph Node Metastasis in a Patient with Relapsed Breast Cancer: Locoregional Event or Distant Metastasis Disease?

INTRODUCTION: Contralateral axillary lymph node metastasis (CAM) is a rare clinical condition in patients with breast cancer. It can be explained from hematogenous spread from the original primary tumor (stage IV) to aberrant regional lymphatic drainage to the contralateral axilla. However, according to the current clinical guidelines, regardless of its origin, CAM is considered as metastatic disease. CASE PRESENTATION: A 68-year-old woman presented with relapsed right breast cancer; lymphoscintigraphy showed only one sentinel lymph node (SLN) in the contralateral axilla (left region). Twenty-four hours later, the patient underwent upper internal quadrantectomy and bilateral selective lymph node biopsy. The final pathological analysis revealed one contralateral macrometastasis (>4 mm) in one left SLN. Subsequently, second-level left lymphadenectomy was performed. Currently the patient is being treated with chemotherapy, with appropriate clinical response. DISCUSSION: Our patient was considered to be node-positive rather than having metastatic disease since the preoperative lymphoscintigraphy demonstrated contralateral lymphatic drainage. Through preoperative scan in patients with relapsed breast cancer with clinically negative lymph nodes and CAM, it is possible to identify those cases that would benefit from therapy with curative intention.

99mTc-HDP Bone Scintigraphy, SPECT/CT, and 18F-FDG PET/CT Diagnosis Imaging of Incidental Pleural Mesothelioma in a Patient With Biochemical Recurrences of Prostate Cancer: Is it Really a Coincidence?

We present the case of a 69-year-old man with history of prostate carcinoma treated with prostatectomy and subsequently with external beam radiotherapy and hormone therapy because of biochemical recurrences. More than 10 years after the diagnosis, follow-up Tc-HDP bone scans and SPECT/CT images demonstrated an incidental diagnosis of osteoblastic pleural plaques that quickly evolve to mesothelioma. PET/CT achieved the definitive diagnosis by guiding the biopsy to the highest and most accessible focus of glucidic hypermetabolism. Our case report raises the association between prostate cancer patients treated with external beam radiotherapy and the development of pleural mesothelioma despite having no history of exposure to asbestos.

[Usefulness of (18)FDG PET-CT scan as a diagnostic tool of fever of unknown origin]. / Utilidad de la tomografía por emisión de positrones con (18)F-Fluorodesoxiglucosa combinada con tomografía computarizada en la orientación diagnóstica de la fiebre de origen desconocido.

BACKGROUND AND OBJECTIVE: Classic fever of unknown origin (FUO) is defined as the presence of fever greater than 38.3°C of at least 3 weeks with an uncertain diagnosis. Identification of the etiology is crucial in guiding further diagnostic procedures and subsequent patient management. The aim of this study was to evaluate the role of fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography combined with computed tomography (PET/CT) in the diagnostic orientation of FUO. MATERIAL AND METHOD: An observational retrospective study was performed, including 30 consecutive patients who had been studied between March 2010 and September 2013. Twenty-six out of 30 patients (86.67%) had a definitive diagnosis after pathologic confirmation in 15 cases, microbiological findings in one patient and clinical and radiological follow-up in 10 patients (mean: 16.38 months). RESULTS: Among the positive scans, malignancy (n=10), inflammatory (n=8), infectious (n=4) and miscellaneous causes (n=1) were identified. (18)F-FDG PET/CT had a diagnostic accuracy of 90.00%, sensitivity of 88.46% (95% confidence interval [95% CI] 76-101), specificity of 100.00% (95% CI 100-100), positive predictive values of 100.00% (95% CI100-100) and negative predictive value of 57.14% (95% CI 20-91). CONCLUSIONS: (18)F-FDG PET/CT provided useful for the etiologic diagnosis of FUO, with high sensitivity and specificity. (18)F-FDG PET/CT has an incremental morphological and functional value, especially indicating the best biopsy site.

18F-DOPA vs. 18F-FDG PET/CT in the ectopic ACTH syndrome due to pulmonary carcinoid tumor / 18F-DOPA vs. 18F-FDG PET/TC en el síndrome de producción ectópica de ACTH por tumor carcinoide pulmonar

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Utilidad de la tomografía por emisión de positrones con 18F-Fluorodesoxiglucosa combinada con tomografía computarizada en la orientación diagnóstica de la fiebre de origen desconocido / Usefulness of 18FDG PET-CT scan as a diagnostic tool of fever of unknown origin

Fundamento y objetivo: La fiebre de origen desconocido (FOD) se define clásicamente como fiebre de más de 3 semanas, con temperatura superior a 38,3 °C en varias ocasiones y sin diagnóstico definitivo tras una semana de hospitalización. Determinar su etiología es fundamental para establecer un tratamiento adecuado del paciente. Nuestro objetivo es valorar la utilidad de la tomografía por emisión de positrones con 18F-Fluorodesoxiglucosa (18F-FDG) combinada con tomografía computarizada (PET/TC) con fluorodesoxiglucosa marcada con flúor 18 (18F-FDG) en la orientación diagnóstica de la FOD. Material y método: Estudio observacional retrospectivo de exploraciones PET/TC realizadas a 30 pacientes consecutivos con FOD entre marzo de 2010 y septiembre de 2013. El diagnóstico definitivo se alcanzó en 26/30 pacientes (86,67%): 15 con confirmación histológica, microbiológica en un caso y con seguimiento clinicorradiológico (media de 16,38 meses) en 10 pacientes. Resultados: Un total de 23 estudios fueron positivos: 10 con etiología tumoral, 8 inflamatoria, 4 infecciosa y uno miscelánea (100% verdaderos positivos). La PET/TC mostró una eficacia en el enfoque diagnóstico del 90,00%, una sensibilidad del 88,46% (intervalo de confianza del 95% [IC 95%] 76-101), una especificidad del 100,00% (IC 95% 100-100), un valor predictivo positivo del 100,00% (IC 95% 100-100) y un valor predictivo negativo del 57,14% (IC 95% 20-91). Conclusiones: La 18F-FDG PET/TC ha demostrado presentar una elevada sensibilidad y especificidad en el diagnóstico etiológico de la FOD, aportando una información morfofuncional valiosa, especialmente en la localización del lugar óptimo para la toma de biopsias (AU)

Background and objective: Classic fever of unknown origin (FUO) is defined as the presence of fever greater than 38.3 °C of at least 3 weeks with an uncertain diagnosis. Identification of the etiology is crucial in guiding further diagnostic procedures and subsequent patient management. The aim of this study was to evaluate the role of fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography combined with computed tomography (PET/CT) in the diagnostic orientation of FUO. Material and method: An observational retrospective study was performed, including 30 consecutive patients who had been studied between March 2010 and September 2013. Twenty-six out of 30 patients (86.67%) had a definitive diagnosis after pathologic confirmation in 15 cases, microbiological findings in one patient and clinical and radiological follow-up in 10 patients (mean: 16.38 months). Results: Among the positive scans, malignancy (n = 10), inflammatory (n = 8), infectious (n = 4) and miscellaneous causes (n = 1) were identified. 18F-FDG PET/CT had a diagnostic accuracy of 90.00%, sensitivity of 88.46% (95% confidence interval [95% CI] 76-101), specificity of 100.00% (95% CI 100-100), positive predictive values of 100.00% (95% CI100-100) and negative predictive value of 57.14% (95% CI 20-91). Conclusions: 18F-FDG PET/CT provided useful for the etiologic diagnosis of FUO, with high sensitivity and specificity.18F-FDG PET/CT has an incremental morphological and functional value, especially indicating the best biopsy site (AU)

Enfermedad de Erdheim-Chester / Erdheim-Chester disease

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