Primary yolk sac tumour of the prostate mimicking small round blue cell tumour.

Prostatic yolk sac tumour is a germ cell tumour with a wide range of age of occurrence, unusual anatomic locations, diverse morphologic patterns, and aggressive biologic behavior, posing challenges both to diagnosis and clinical management. We report a rare case of primary yolk sac tumour of the prostate with extensive local and liver metastasis, the latter of which exhibited sheets of small blue cells expressing CD99 and focal sall4 on biopsy. Positivity for CD99 and gata3 in the initial biopsy raised the differential diagnosis of Ewing sarcoma and poorly differentiated carcinoma. The primary tumour demonstrated an admixture of solid and glandular growth patterns and occasional Schiller-Duval bodies. A panel of immunohistochemical stains showing positivity for AE1/3, sall4, cdx2, and focal alpha-fetoprotein, and negativity for oct-4, facilitated the diagnosis. A thorough review of the literature and our current report indicate that a large tumour load, incomplete tumour resection, limited response to preoperative neoadjuvant chemotherapy, and late stage of the disease are predictive factors for a poor clinical outcome.

Extent of microstructural white matter injury in postconcussive syndrome correlates with impaired cognitive reaction time: a 3T diffusion tensor imaging study of mild traumatic brain injury.

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) may be a useful index of microstructural changes implicated in diffuse axonal injury (DAI) linked to persistent postconcussive symptoms, especially in mild traumatic brain injury (TBI), for which conventional MR imaging techniques may lack sensitivity. We hypothesized that for mild TBI, DTI measures of DAI would correlate with impairments in reaction time, whereas the number of focal lesions on conventional 3T MR imaging would not. MATERIALS AND METHODS: Thirty-four adult patients with mild TBI with persistent symptoms were assessed for DAI by quantifying traumatic microhemorrhages detected on a conventional set of T2*-weighted gradient-echo images and by DTI measures of fractional anisotropy (FA) within a set of a priori regions of interest. FA values 2.5 SDs below the region average, based on a group of 26 healthy control adults, were coded as exhibiting DAI. RESULTS: DTI measures revealed several predominant regions of damage including the anterior corona radiata (41% of the patients), uncinate fasciculus (29%), genu of the corpus callosum (21%), inferior longitudinal fasciculus (21%), and cingulum bundle (18%). The number of damaged white matter structures as quantified by DTI was significantly correlated with mean reaction time on a simple cognitive task (r = 0.49, P = .012). In contradistinction, the number of traumatic microhemorrhages was uncorrelated with reaction time (r = -0.08, P = .71). CONCLUSION: Microstructural white matter lesions detected by DTI correlate with persistent cognitive deficits in mild TBI, even in populations in which conventional measures do not. DTI measures may thus contribute additional diagnostic information related to DAI.

Eye-target synchronization in mild traumatic brain-injured patients.

Eye-target synchronization is critical for effective smooth pursuit of a moving visual target. We apply the nonlinear dynamical technique of stochastic-phase synchronization to human visual pursuit of a moving target, in both normal and mild traumatic brain-injured (mTBI) patients. We observe significant fatigue effects in all subject populations, in which subjects synchronize better with the target during the first half of the trial than in the second half. The fatigue effect differed, however, between the normal and the mTBI populations and between old and young subpopulations of each group. In some cases, the younger (40 years old) normal subjects. Our results, however, suggest that further studies will be necessary before a standard of "normal" smooth pursuit synchronization can be developed.