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.

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.

Value of the negative PET-FDG in the middle term follow-up of differentiated thyroid cancer in patients with negative 131 I-Na scan and elevated thyroglobulin serum levels.

OBJECTIVE: This study has aimed to analyze the evolution of patients diagnosed with differentiated thyroid carcinoma (DTC) with a negative (131)I-Na whole body scan (WBS), high levels of serum thyroglobulin (Tg) and negative (18F)fluorodeoxyglucose positron emission tomography (PET-FDG) study. MATERIAL AND METHODS: Twenty-three patients diagnosed and treated for DTC were studied retrospectively. Patients were aged between 23 and 83 and had shown, between January 2001 and December 2002, negative WBS, Tg values in a range of suspected recurrence or metastasis (Tg>2 ng / mL with thyroid hormone withdrawal) and a negative PET-FDG study. The patients were monitored clinically, radiologically and analytically for a minimum period of 4 years. After this, a new evaluation was made of their state of disease with a control WBS, also observing the evolution of Tg. All WBS were performed with a 185 MBq diagnostic dose of (131)I-Na. RESULTS: In 18/23 patients, Tg decreased and in 5 it increased. Four patients (17%) were free of active disease (negative WBS Tg<2 ng / mL). A total of 16 patients (70%) were free of disease according to the WBS but had elevated Tg. Three patients (13%) had disease and high levels of Tg, two of them with positive WBS and the third with (99m)Tc-MIBI scan and CT positive. CONCLUSIONS: Most patients with a negative WBS, high Tg serum levels and negative FDG PET had good evolution, with descending Tg levels, normal levels even being reached in a significant percentage of them.