Heterotopic pancreas: typical and atypical imaging findings.

Heterotopic pancreas is a common condition often encountered during laporotomy or autopsy. Prospective radiographic diagnosis is challenging because of the variable imaging appearances. The purpose of this review is to present the typical and atypical appearances of heterotopic pancreas on imaging studies. Familiarity with the spectrum of radiological findings in conjunction with biochemical markers is helpful to improve diagnostic accuracy.

Orbital hemangiopericytoma and solitary fibrous tumor: a morphologic continuum.

Solitary fibrous tumors (SFT) and hemangiopericytomas (HPC) are soft tissue tumors with known histologic and immunohistochemical overlap. A series of these tumors located in the orbit were analyzed in order to determine whether they could be re-classified based on currently recognized histologic criteria. Ten orbital spindle cell lesions, all of which were positive for CD34 antigen, were examined. Diagnostic criteria for SFT included a cytologically bland spindle cell lesion with variable cellularity and focal dense collagenization with diffuse, strong CD34 reactivity, while the criteria for HPC required a more monotonous cellular proliferation without significant variability in cellularity, a "staghorn" vascular pattern, minimal collagenization, and focal or absent CD34 staining. Tumors with typical histologic and immunohistochemical features of HPC or SFT were diagnosed as HPC and SFT, respectively. Those tumors with histologic or antigenic profiles not classic for HPC or SFT were defined as 'indeterminate.' Three lesions were classified as SFT and 1 tumor was diagnosed as HPC through use of the above-cited histologic criteria. All lesions showed positive staining of tumor cells with CD34 antigen in varying amounts and were negative for cytokeratin AE1-3, epithelial membrane antigen, CD68, and Factor XIIIa. One solitary fibrous tumor focally stained for S-100 protein and 1 hemangiopericytoma was focally positive for HHF-35. Of the 10 analyzed tumors, 6 were classified as 'indeterminate.' Furthermore, 1 lesion whose primary histology was that of an SFT recurred 9 years later with an appearance consistent with an 'indeterminate' lesion. Our results call into question the present histologic separation of HPC and SFT in the orbit. As in other sites, including deep soft tissue, these data suggest that SFT and HPC are 2 lesions whose morphologic features are best interpreted to exist along a continuum, rather than 2 lesions with distinctly defined histopathology.

Amyloid goiter: report of two cases and review of the literature.

OBJECTIVE: To describe two recent cases of amyloid goiter that occurred in two patients with a history of diffuse enlargement of the thyroid gland, progressing over several years' time. METHODS: We reviewed the medical histories as well as the histologic, immunohistochemical, and electron microscopic findings in these patients. RESULTS: Assessment of the clinical records of a 59-year-old man and a 64-year-old woman revealed histories that included chronic psoriasiform arthritis and asthma in conjunction with chronic obstructive pneumonia and bronchiectasis. In both cases, total thyroidectomy was performed. On histologic examination of both thyroid glands, the appearance was characterized by moderate to severe distortion of the normal thyroid architecture by amyloid in a perifollicular distribution and focally abundant interfollicular adipose tissue. In both cases, the amyloid stained intensely positive with Congo red, which bleached after treatment with potassium permanganate. Immunohistochemical staining patterns were consistent with AA amyloid, and electron microscopy showed nonbranching 9-nm fibrils consistent with amyloid. CONCLUSION: The diagnosis of amyloid goiter should be suspected in patients with a diffusely enlarging thyroid gland and an appropriate clinical history.

In vivo release of neuroactive amino acids from the inferior colliculus of the guinea pig using brain microdialysis.

Microdialysis techniques were used to measure in vivo release of neuroactive amino acids from the central nucleus of the inferior colliculus (ICC) in anesthetized guinea pigs. Concentric dialysis probes were implanted in the ICC and perfused with Ringer solution of various compositions at a flow rate of 2.0 microliters/min. Consecutive 10-min fractions of the dialysate were collected for up to 3 h under different experimental conditions, frozen and assayed for amino acid content by high performance liquid chromatography (HPLC). There was an initial high outflow of amino acids which declined to stable baseline levels after 2 h. Following this stabilization period, perfusion with a medium containing 100 mM KCl produced an increase in the extracellular levels of aspartate (Asp), glutamate (Glu), gamma-aminobutyric acid (GABA) and glycine (Gly). Only the increases in GABA and Gly were statistically significant. None of the increases occurred in the presence of 2.0 mM cobalt suggesting the release of amino acids is calcium dependent. Histological examination revealed that tissue damage was minimal and largely confined to the immediate vicinity of the probes. We were also able to show that the blood brain barrier (BBB) appeared to heal 2 h after probe implantation. Thus, following intravenous injection of [3H]alpha-aminoisobutyric acid (AIB), which does not cross the intact BBB, no isotope was recovered in the dialysate. These results demonstrate that microdialysis is a unique and suitable method to monitor changes in the extracellular levels of amino acid neurotransmitters in a central auditory structure.(ABSTRACT TRUNCATED AT 250 WORDS)