The Levator Claviculae Muscle Presenting as a Neck Mass.

The levator claviculae muscle is an uncommonly encountered muscle variant, occurring in 1% to 2% of the human population. Most accounts of the levator claviculae muscle have been reported in association with routine cadaveric examination and as an incidental finding by computed tomography (CT) and magnetic resonance (MR) imaging. We report a case of this variant muscle presenting as a soft-tissue mass within the neck of a young male. Furthermore, we discuss the embryologic origin, imaging features and clinical implication.

Solid pseudopapillary tumor of the pancreas.

Solid pseudopapillary tumor is a rare tumor accounting for 1-2% of exocrine neoplasms involving the pancreas. This typically benign tumor is predominately found in young females of non-Caucasian descent between the second and fourth decades of life. Despite the reported increasing incidence of this neoplasm, many physicians are unfamiliar with this tumor, which may lead to uncertainty of diagnosis and treatment. While further delineating the clinical and imaging features of this tumor, we present two cases with review of the literature.

Identification of the sentinel node by ultrasonography in patients with breast cancer.

BACKGROUND: Identification of the sentinel node (SN) in patients with breast cancer is done by tracking a radioactive tracer, a vital dye, or both, as the marker(s) reach the axilla. Replacing this method with ultrasonographic (US) recognition of the SN could eventually spare patients the need for systemic anesthesia, permit minimally invasive outpatient biopsy of the node, and allow the formulation of a precise therapeutic plan before a definitive surgical procedure. METHODS: Eighty-eight axillae of 84 patients with a histologic diagnosis of breast cancer were studied by injecting the subareolar area of the affected breast(s) with technetium 99 and an iron preparation before the planned surgical procedure and SN biopsy. An axillary US scan was performed in all patients before the injection of the markers. After induction of anesthesia, the SN was identified, needle-localized, and extracted under US guidance. Confirmation that the SN was retrieved was established by concordance with the audible gamma signal, unless there was none. All extracted nodes had iron stains performed. RESULTS: All except three of the SNs were identified with US after the iron marker was injected, and all except six were identified by their radioactive signal. One of the SNs undetected on US was identified by its radioactive tracer, and the other two, although seen on US, had neither a gamma signal nor concordant iron deposits. All other SNs identified with US had a concordant audible signal when there was one, and all had concordant iron deposits on microscopy. Of the six SNs without a gamma signal, three without preincision activity were identified with US; three with neither a preincision nor an ex vivo signal were seen with US, but two of these were the SNs without a concordant iron deposit. CONCLUSIONS: Using an iron preparation, the SN in patients with breast cancer can be identified with US with an accuracy equal to and perhaps better than that achieved with a radioactive tracer. These findings may change the current diagnostic model and affect the therapeutic algorithm of breast cancer patients.

The effect of skull volume and density on differentiating gray and white matter on routine computed tomography scans of the head.

Increased volume and density of the skull makes computed tomography differentiation of gray and white matter (GM and WM, respectively) more difficult. The purpose of this investigation was to study the effects of skull volume and bone density on GM and WM differentiation. A total of 21 patients with thick skulls and 22 controls were included in this study. Three consecutive slices from the computed tomography scan were analyzed. The basal ganglia had to be visualized on at least 1 slice. Calvarial volume measurement, mean pixel value in each slice, and Hounsfield unit difference between WM and GM, were compared between the thick-skulled and control groups. The mean bone volume of each slice in the thick-skulled group was 55.7, 54.3, and 56 mL, whereas the mean volume of each slice in the normal group was 39.3, 38.5, and 39.9 mL (P < 0.001). In our series, patients with thick skulls had 41% more bone volume than the normal group. The mean skull pixel value in each slice was 935.9 in patients with thick skulls and 987 in patients in the normal group. There was no difference between right and left sides of the same group of patients. Patients with larger volumes of skull have significant decrease in the Hounsfield unit of the GM and WM compared with the control group. As a result, diagnosing any low-contrast brain abnormality including early/subtle infarction in subjects with a thicker calvarium may be more difficult.