The iliopsoas compartment, a posterior boundary of the retroperitoneum, is comprised of the psoas major, psoas minor and iliac muscles. The symptoms picture in patients presenting with pathological involvement of this compartment may show a wide range of nonspecific clinical presentations that may lead to delayed diagnosis. However, in the search of an etiological diagnosis, it is already known that inflammation, tumors, and hemorrhages account for almost all the lesions affecting the iliopsoas compartment. By means of a retrospective analysis of radiological studies in patients with iliopsoas compartment lesions whose diagnosis was confirmed by anatomopathological evaluation or clinical follow-up, we have reviewed its anatomy as well as the main forms of involvement, with the purpose of identifying radiological signs that may help to narrow down the potential differential diagnoses. As each lesion is approached we will discuss the main radiological findings such as presence of gas in pyogenic abscesses, bone destruction and other bone changes of vertebral bodies in lesions secondary to tuberculosis, involvement of fascial planes in cases of neoplasms, and differences in signal density and intensity of hematomas secondary to hemoglobin degradation, among others. So, we have tried to present cases depicting the most frequent lesions involving the iliopsoas compartment, with emphasis on those signs that can lead us to a more specific etiological diagnosis.

Keywords: Iliopsoas muscle, Psoas muscle, Computed tomography, Abscesses, Neoplasms

OBJECTIVE: The present study was aimed at establishing the frequency of renal/perirenal and extrarenal computed tomography findings in patients with acute pyelonephritis, and evaluating the interobserver agreement. MATERIALS AND METHODS: Retrospective study based on the analysis of computed tomography images of 47 patients with clinical and laboratory findings of acute pyelonephritis. Two independent observers evaluated the main renal/perirenal and extrarenal alterations. The frequency of tomographic findings and interobserver agreement were analyzed by the kappa (k) test. RESULTS: The frequency of tomographic findings for the several parameters was the following: striated nephrogram, 100%; renal enlargement, 65%; perirenal fat heterogeneity, 62.5%; renal calculi, 16.6%; abscesses, 21%; pleural effusion, 36%; thickened gallbladder wall, 32.5%; periportal edema, 32.5%. The k test for interobserver agreement demonstrated reproducibility ranging between moderate (k = 0.511 for renal enlargement) to almost perfect (k = 0.87 for striated nephrogram) for all of the parameters analyzed, except for perirenal fat heterogeneity (k = 0.268). CONCLUSION: The frequency of findings of acute pyelonephritis on computed tomography is high. Overall, striated nephrogram was the most frequent finding. Peri- and extra-renal alterations were found in about 2/3 of the cases. Computed tomography demonstrated a good interobserver agreement.

Keywords: Acute pyelonephritis, Kidney, Computed tomography, Reproducibility

The authors report an unusual presentation of a voluminous neck schwannoma in a 53-year-old female that presented with a three-year history of progressive weakness associated with impaired movement of the limbs. Neurological examination revealed postural instability, unstable and paraparetic gait, tetraparesis and dyspnea. A preoperative magnetic resonance imaging of the neck revealed an expansive, extradural, well-circumscribed lesion, with soft-tissue attenuation, at the level of C1-C2 vertebral bodies. During surgery, the tumor was found to be extradural, lateral to the cervical spinal cord, attached to the C1 left nerve root and extending upwards through the foramen magnum. Histopathological analysis of the resected specimen confirmed the diagnosis of schwannoma. The patient showed a favorable outcome with progressive improvement of the symptoms. Magnetic resonance imaging proved to be valuable in the detection and evaluation of the lesion, although the definite diagnosis was achieved only after histopathological studies. We concluded that magnetic resonance imaging for early diagnosis and prompt surgical resection seems to be the best approach to achieve good prognosis.

Keywords: Schwannoma, Central nervous system, Foramen magnum