Sentinel lymph node biopsy in N+ breast cancer with conversion into N0 after neoadjuvant chemotherapy. / Biopsia selectiva de ganglio centinela en carcinomas de mama N+ convertidos a N0 después de quimioterapia neoadyuvante.

OBJECTIVE: Sentinel lymph node biopsy (SLNB) usefulness in breast carcinoma N+ converted to N0 after neoadjuvant chemotherapy (NC). MATERIAL AND METHODS: Descriptive study including 16 females with infiltrating carcinoma with lymphatic metastasis confirmed by biopsy, leaving a metallic marker (MM) in pathological lymph nodes (LN). All patients underwent NC reaching a complete radiological response in LN. Lymphoscintigraphy was performed after 99mTc nanocoloid injection, obtaining planar images and SPECT/CT. Lymphatic drainage and concordance of sentinel node (SN) with MM was analyzed. RESULTS: SN was visualized in lymphoscintigraphy in 93.7% of cases. The SN coincided with the MM in 12/15 cases on SPECT/CT. The SLNB technique was completed on 14/16 patients, intraoperatively locating the GC in all of them. The SN was negative in 10 cases, 3 cases presented macrometastases and 1 micrometastases. Axillary lymphadenectomy (AL) was performed in a case of macrometastasis with>15,000cp/µARNm CK-19, absence of drainage and in one case that showed no coincidence with the MM due different Berg's level location. These last two cases presented lymph node metastasis. In the other two cases with not coincidence between the SN and the MM, a total of 4 lymph nodes were removed, showing no evidence of metastasis. Patients without AL were followed up for an average of 10 months (range 6-17), with no evidence of lymph node involvement. CONCLUSION: SLNB in breast cancer with conversion into N0 after neoadjuvant treatment is a technique with good results and a low false negative rate.

Usefulness of 18F-FDG PET/CT in a case of suspected vascular graft infection. / Utilidad de la 18F-FDG PET/TC en un caso de sospecha de infección de injerto vascular.

Vascular prosthetic graft infection (VPGI) is associated with high mortality and morbidity. An early and accurate diagnosis is essential in order to give the most appropriate treatment. The case is presented of a 74 year old male subjected to an aortobifemoral bypass graft, with clinical suspicion of VPGI with inconclusive tests. Later on an 18F-FDG PET/CT study showed a pathological uptake, suggestive of periprosthetic infection, as well as an incidental pulmonary lesion, suggestive of a primary neoplasm. A new 18F-FDG PET/CT showed a significant improvement in the uptake by the vascular graft after prolonged antibiotic treatment. 18F-FDG is a promising tracer for detecting VPGI as the accumulated activated white cells at the infection site have a high demand for 18F-FDG, and could help define the response to antibiotic treatment.

The role of 18FDG, 18FDOPA PET/CT and 99mTc bone scintigraphy imaging in Erdheim-Chester disease.

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocitosis, characterized by multisystemic xanthogranulomatous infiltration by foamy histiocytes that stain positively for CD68 marker but not express CD1a and S100 proteins. Etiology and pathogenesis are still unknown and only about 500 cases are related in the literature. Multisystemic involvement leads to a wide variety of clinical manifestations that results in a poor prognosis although recent advances in treatment. We present the clinical, nuclear medicine findings and therapeutic aspects of a serie of 6 patients with histopathological diagnosis of ECD, who have undergone both bone scintigraphy (BS) and 18F-fluorodeoxyglucose (18FDG)-PET/CT scans in our institution. A complementary 18F-fluorodopa (18FDOPA)-PET/CT was performed in one case. Three different presentations of the disease were observed in our casuistic: most indolent form was a cutaneous confined disease, presented in only one patient. Multifocal involvement with central nervous system (CNS) preservation was observed in two patients. Most aggressive form consisted in a systemic involvement with CNS infiltration, presented in three patients. In our experience neurological involvement, among one case with isolate pituitary infiltration, was associated with mortality in all cases. 18FDG-PET/CT and BS were particularly useful in despite systemic involvement; locate the site for biopsy and the treatment response evaluation. By our knowledge, 18FDOPA-PET/CT not seems useful in the initial staging of ECD. A baseline 18FDG-PET/CT and BS may help in monitoring the disease and could be considered when patients were incidentally diagnosed and periodically 18FDG-PET/CT must be performed in the follow up to evaluate treatment response.

[Utility of single photon emission computed tomography-computed tomography in selective sentinel lymph node biopsy in patients with melanoma]. / Utilidad de la tomografía de emisión de fotón único-tomografía computarizada en la biopsia selectiva del ganglio centinela en pacientes con melanoma.

OBJECTIVE: To assess the contribution of SPECT-CT lymphoscintigraphy in selective sentinel lymph node biopsy (SLNB) in patients with newly diagnosed malignant melanoma. MATERIAL AND METHODS: A prospective study was made between July 2009 and October 2010. It included 63 patients diagnosed with melanoma (32 men and 31 women) with mean age of 55 years (range: 25-88) and inclusion criteria for SLNB. The melanomas were located as follows: 28 in trunk, 5 in head and neck, 16 in upper limbs and 17 in lower limbs. Three patients had two melanomas. Preoperative lymphoscintigraphy was performed after pericicatricial/perilesional injection of 74MBq of (99m)Tc-labeled nanocolloid human serum albumin, obtaining early planar images, late whole body study and sectorial images and SPECT-CT in the area of interest. Planar scintigraphy findings were compared with SPECT-CT. RESULTS: The sentinel node (SN) was localized by planar imaging in 62/63 (98%) of patients. SPECT-CT study located the SN in all the patients with a detection rate of 100%. The number of SNs detected with SPECT-CT was higher than with the planar study in 27 patients. The SPECT-CT provided additional information (change in location and/or in its accuracy in the localization of location uncertain SN) in 14/63 (22.2%) patients, involving changes in the surgical approach and lymph node staging. CONCLUSION: SPECT-CT detects a higher number of SN than planar lymphoscintigraphy in patients with melanoma. Its contribution is more relevant in the melanomas located on the trunk, head and neck. SPECT-CT modified the SN location by 22% compared to planar scan findings, facilitating a correct surgical approach.