Bilateral Simultaneous Temporal Relapses of Medulloblastoma.

Supratentorial relapses are a common component of medulloblastoma after failure of treatment. Craniospinal irradiation (CSI) to cerebrospinal fluid-bearing areas is an essential part of the management of these tumors both in adults and children. Failure of treatment in specific anatomical regions can be attributable to technical inaccuracies in CSI technique leading to radiation underdosing in such areas. We present two cases of patients with bilateral simultaneous metastasis of a primary medulloblastoma treated, in both cases, four years before the recurrence. In both patients the tumors were mirror images, at the right and left temporal pole. Radiotherapeutic plans were analyzed in both cases, and a possible mechanism determining the pattern of relapse is discussed. We consider, in agreement with the literature, that a prone position during treatment, shielding blocks at the cribiform/subfrontal region, and anatomic inadequacies in the CSI fields could have contributed to the presented pattern of relapse.

Immunohistochemical features of giant cell ependymoma of the filum terminale with unusual clinical and radiological presentation.

BACKGROUND: Giant cell ependymoma of the filum terminale is a rare variant, generally manifested as a well-circunscribed intradural mass with an indolent biological behavior. CASE PRESENTATION: We describe the case of a 48-year-old Mexican female who non-relevant past medical history, that developed a GCE of the filum terminale. Magnetic resonance imaging and computed tomography revealed the presence of an intra-axial tumor extending from L3 to L5 with extra-medullary invasion. Therefore the tumor was considered unresectable and only incisional biopsy was obtained, establishing the tentative diagnosis of a poorly differentiated neoplasia. A second evaluation of the case revealed the presence of numerous non-cohesive pleomorphic giant cells with intranuclear inclusions and broad eosinophilic cytoplasm, alternating with intermediate size cells with round, hyperchromatic nuclei and forming a perivascular pseudo-rosettes pattern. The ependymal phenotype was supported by light microscopy and corroborated by immunohistochemistry analysis. The patient was subsequently treated with radiotherapy 54Gy. She is alive after a 27-month follow-up, with residual disease, difficulty ambulating and pain. CONCLUSIONS: GCE of filum terminale may have an atypical clinical and radiological presentation, albeit with invasive characteristics and anaplasia on histologic analysis. However, its biological behavior is indolent and associated to longer survival. Due to the presence of giant cells, the differential diagnosis of other primary neoplasias at that site were considered, including paraganglioma, malignant peripheral nerve sheath tumors as well as metastatic malignant melanoma, adrenal carcinoma, thyroid gland carcinoma and urothelial carcinoma, that may all harbor giant cells.

Implementation of intensity modulated radiotherapy for prostate cancer in a private radiotherapy service in Mexico.

Intensity modulated radiation therapy (IMRT) allows physicians to deliver higher conformal doses to the tumour, while avoiding adjacent structures. As a result the probability of tumour control is higher and toxicity may be reduced. However, implementation of IMRT is highly complex and requires a rigorous quality assurance (QA) program both before and during treatment. The present article describes the process of implementing IMRT for localized prostate cancer in a radiation therapy department. In our experience, IMRT implementation requires careful planning due to the need to simultaneously implement specialized software, multifaceted QA programs, and training of the multidisciplinary team. Establishing standardized protocols and ensuring close collaboration between a multidisciplinary team is challenging but essential.

Expression of Epstein-Barr virus-encoded latent membrane protein (LMP-1), p16 and p53 proteins in nonendemic nasopharyngeal carcinoma (NPC): a clinicopathological study.

BACKGROUND AND AIMS: Although the latent membrane protein type 1 (LMP1) is frequently expressed in Epstein-Barr virus (EBV) malignancies, its contribution to the pathogenesis of nasopharyngeal carcinoma (NPC) is not fully defined. LMP1 functions as a viral mimic of the TNFR family member engaging a number of signaling pathways that induce morphological and phenotypic alterations. This study aimed to investigate the LMP1 expression and EBV infection in relation to clinical outcome and survival in a series of Mexican NPC patients. We also studied expression of p16 and p53 proteins. METHODS: We analyzed in 25 tumor specimens the expression of LMP1, p16 and p53 by immunohistochemistry (IHC) and EBV presence by IHC/in situ hybridization. Differences in clinical outcome and survival in relation to protein expression were correlated through χ(2) statistics and Kaplan-Meier survival curves. RESULTS: Our results showed a rate of 92% (23/25) of EBV infection. The expressions of LMP-1, p16 and p53 proteins were 40.0, 44.0 and 40.0%, respectively. LMP-1 immunoexpression was more common in older patients (>50 vs. <50 years old, p = 0.02) and with parapharyngeal space invasion (p = 0.02). The presence of metastatic disease at diagnosis (p = 0.03), distant recurrence disease (p = 0.006) and shorter distance recurrence-free survival (p = 0.05) was associated with lack of p16. CONCLUSIONS: In our series, EBV infection rates are particularly high for nonendemic NPC, although without a statistically significant difference in overall survival, LMP1 and p16 expression was correlated with poorer clinical prognosis. Probably, LMP1 and p16 detection identify a worse clinical prognosis in NPC patient subgroup.