Biomedical subjects
B J Wagner
Publications and source records attributed to B J Wagner.
Congenital uterine malformations.
With the advent of newer imaging techniques, the radiologist is now able to make very precise and accurate diagnoses of congenital uterine malformations and their complications. Because these anomalies are associated with reproductive dysfunction, they are often discovered during an infertility evaluation. By imaging parallel to the long axis of the uterus, the external contour can be evaluated, obviating laparoscopy for differentiating septate from bicornuate uteri. Obstructed uterovaginal anomalies (e.g., hematometros, hematometrocolpos), an important complication of abnormal müllerian duct development, can occur at any time from the newborn period to adulthood. Determining the site of obstruction is imperative for planning the proper surgical approach. To understand these malformations better, we review the relevant embryology. The most widely accepted classification scheme is discussed in detail, with an emphasis on diagnosis, prognosis, and therapeutic options.
Attention deficit hyperactivity disorder: current concepts and underlying mechanisms.
TOPIC: Neuropsychological concentration of attention deficit hyperactivity disorder (ADHD). PURPOSE: Survey of current understanding of underlying neural systems and pathways involved in ADHD and the relationship to specific behavioral patterns. SOURCES: Literature review, author's experience in neuropsychological assessment and clinical treatment. CONCLUSIONS: Clinicians will be able to specify treatment interventions designed to compensate for specific behavioral patterns and functional deficits.
Adult renal hamartomas.
Renal angiomyolipomas, the most familiar of the renal hamartomas, are well known to radiologists, despite being uncommon and of limited clinical importance, because angiomyolipomas represent one of the few lesions for which a specific diagnosis can be achieved on the basis of radiologic findings in the majority of cases. Because of the diversity in the relative amounts of various cellular components and because of the occasional association with acute hemorrhage, the radiologic features of angiomyolipomas can be somewhat varied. At sonography, angiomyolipomas appear echogenic with acoustic shadowing. At computed tomography (CT), these lesions typically appear as well-marginated, small (< 5 cm in size), cortical masses of predominantly fat attenuation with heterogeneous soft-tissue attenuation interspersed throughout. Some angiomyolipomas are larger and poorly marginated because of hemorrhage. Typical angiomyolipomas are largely composed of fat; those uncommon tumors without demonstrable fat cannot be radiologically distinguished from renal cell carcinoma. Renal leiomyoma, a lesion that pathologically overlaps with angiomyolipoma to some degree, has a quite different imaging appearance (ie, homogeneous, without detectable fat) that cannot be distinguished from malignant renal lesions.
From the archives of the AFIP. Genitourinary rhabdomyosarcoma in children: radiologic-pathologic correlation.
Rhabdomyosarcoma is the most common tumor of the lower genitourinary tract in children in the first 2 decades of life. Most cases of genitourinary rhabdomyosarcoma are of the embryonal histologic subtype and include tumors of the bladder, prostate, testes and paratesticular sites, penis, perineum, vagina, and uterus. The natural history, pattern of metastatic spread, treatment, and prognosis of childhood rhabdomyosarcoma vary with the anatomic site of the lesion. In children with rhabdomyosarcoma of the bladder or prostate, presenting signs and symptoms include urinary or fecal retention, dysuria, urinary tract infection, and hematuria. Paratesticular rhabdomyosarcoma produces painless scrotal swelling, which may be ignored until the tumor has reached a large size. Vaginal tumors may manifest as a prolapsing mass in the introitus. Radiologic studies of children with genitourinary rhabdomyosarcoma reflect the nonspecific gross features of the tumor, which may be ill defined with infiltrative margins or well circumscribed by a pseudocapsule of compressed tissue. The botryoid variant of embryonal rhabdomyosarcoma results when submucosal tumor produces a polypoid mass resembling a cluster of grapes within a hollow structure. Botryoid morphology is characteristic, but not specific, for rhabdomyosarcoma within the vagina or urinary bladder, since yolk sac tumor and "tumoral" cystitis may have a similar appearance. Invasion of adjacent structures by the primary tumor may make the precise anatomic origin of genitourinary rhabdomyosarcoma difficult to determine on cross-sectional images. Recent refinements in multidisciplinary therapeutic regimens combining chemotherapy, radiation therapy, and surgery have dramatically improved outcome for children with genitourinary rhabdomyosarcoma. Diagnostic imaging plays an important role in monitoring response to therapy.
Imaging and pathologic features of myelolipoma.
Myelolipoma is a benign tumor consisting of mature fat interspersed with hematopoietic elements resembling bone marrow. Imaging findings in a large series of pathologically proved cases of myelolipoma were correlated with the pathologic and histologic features of the lesions. Myelolipoma manifests in four distinct clinicopathologic patterns: isolated adrenal myelolipoma, adrenal myelolipoma with hemorrhage, extraadrenal myelolipoma, and myelolipoma associated with other adrenal disease. Myelolipoma is difficult or impossible to detect at plain radiography unless the lesion is large and predominantly fatty. At ultrasound, myelolipoma often has heterogeneous echogenicity due to its typically nonuniform architecture. Computed tomography (CT) frequently demonstrates large amounts of fat with areas of interspersed higher-attenuation tissue. At magnetic resonance imaging, predominantly fatty areas usually have increased signal intensity on T1-weighted images and moderate hyperintensity complicated by the presence of marrowlike elements in the corresponding regions on T2-weighted images. The imaging appearance of myelolipoma is altered by the presence of hemorrhage. In such cases, CT is the most accurate method for evaluation. Knowledge of the imaging characteristics of myelolipoma usually allows presumptive diagnosis, although percutaneous needle biopsy may be needed to confirm the diagnosis in cases of extraadrenal myelolipoma. Surgical excision is unnecessary unless the diagnosis is unclear or the lesion is symptomatic. Asymptomatic, nonhemorrhagic myelolipomas do not require therapy.
Transitional cell carcinoma of the urinary tract: radiologic-pathologic correlation.
The urothelium is a target tissue for carcinogens that lead to the development of transitional cell carcinomas (TCCs), both synchronous and metachronous. Although there are pathologic and imaging features common to transitional cell tumors occurring anywhere in the genitourinary tract, certain findings are more typical of tumors of the renal pelvis, ureter, or urinary bladder. A slightly irregular, fixed mass arising from any urothelial surface is characteristic of TCC. Although such masses are usually confined to the collecting system lumina, larger lesions that arise in the renal pelvis may extend into the renal parenchyma, typically in an infiltrative pattern that preserves the reniform shape. In contrast to the rapidly developing mural edema associated with obstructing calculi, the relatively slow growth of ureteral TCC allows for gradual expansion of the ureteral lumen around the tumor and is less likely to produce acute renal colic. Focal wall thickening, either eccentric or circumferential, may also be a manifestation of TCC of the ureter or, less commonly, other portions of the urinary tract. The urinary bladder is the most common site of TCC; lesions are generally confined to the lumen and typically do not extend beyond the bladder wall until quite large.
MR imaging of the adrenal gland: radiologic-pathologic correlation.
Complex physiologic and neoplastic processes affect the adrenal glands. An appreciation of the gross pathologic and histologic correlates of disease aids in understanding the mechanisms by which diagnostic imaging helps characterize adrenal masses. Computed tomographic (CT) densitometry and chemical shift magnetic resonance (MR) imaging would seem to be the most reliable tools in determining whether a given adrenal mass is specifically an adenoma. Such a determination is made on the basis of the presence of substantial amounts of intracytoplasmic lipid. Thus, although a homogeneous mass with a CT attenuation of less than 10 HU or a decrease in signal intensity at opposed-phase MR imaging is diagnostic for adenoma, lesions that do not have these features are indeterminate and may necessitate biopsy. Adrenal myelolipoma also has a distinctive imaging appearance that reflects the presence of macroscopic fat deposits. Diagnosis of adenoma or adrenal myelolipoma is very helpful in the assessment and treatment of asymptomatic patients with adrenal masses and may make biopsy unnecessary. In patients with clinical or biochemical evidence of adrenal disease, MR imaging helps confirm the presence of a mass and allows localization and further characterization of the lesion.
Sex cord-stromal and steroid cell tumors of the ovary.
Gonadal cell types that derive from the coelomic epithelium (sex cords) or mesenchymal cells of the embryonic gonads include granulosa cells, theca cells, fibroblasts, Leydig cells, and Sertoli cells. Ovarian tumors of these cell types are called sex cord-stromal tumors. This group of tumors represents approximately 8% of ovarian neoplasms and affects all age groups. The more common types are granulosa cell tumors (GCTs), fibrothecomas, and Sertoli-Leydig cell tumors. Sex cord-stromal tumors are of interest partly because of their hormonal effects, which are rare for other ovarian neoplasms. These effects include estrogenic effects (pseudoprecocious puberty, endometrial bleeding, endometrial hyperplasia and carcinoma) and virilization. The variety of gross appearances of these tumors, ranging from large multicystic masses to small solid masses, would appear to preclude a specific radiologic diagnosis. However, in many patients, both clinical and radiologic clues can suggest the diagnosis, including predominantly fibrous content at ultrasound or magnetic resonance imaging (fibrothecoma), large hemorrhagic multicystic mass in a child with pseudoprecocious puberty (juvenile GCT), and associated syndromes such as Peutz-Jeghers syndrome (sex cord tumor with annular tubules) or Ollier disease and Maffucci syndrome (juvenile GCT).
From the archives of the AFIP. Infiltrative renal lesions: radiologic-pathologic correlation. Armed Forces Institute of Pathology.
Most renal masses exhibit an expansile growth pattern characterized by radial tumor enlargement that displaces normal renal parenchyma and forms spherical, often exophytic, lesions. These expansile masses have pushing margins that impress adjacent normal renal parenchyma but do not infiltrate it; this behavior results in a well-defined, encapsulated appearance at both radiologic and gross pathologic examination. In contrast, certain disease processes involve the kidney in an infiltrative fashion by using the normal renal architecture as scaffolding for interstitial growth. These infiltrative renal lesions lack a sharp border of demarcation with the normal parenchyma and therefore demonstrate ill-defined zones of transition between the lesion and normal parenchyma. Although infiltrative lesions frequently enlarge the kidney, its reniform shape is usually maintained. Cross-sectional imaging can often help distinguish infiltrative from expansile growth patterns through analysis of the parenchymal interface between the process and the kidney, the effect of the lesion on the collecting system and renal sinus, and the overall renal morphology. A wide variety of neoplastic and inflammatory conditions characteristically involve the kidney by cellular infiltration. Although considerable overlap of the imaging features exists among the various infiltrative processes, the correct diagnosis may be suspected when the clinical data and associated radiologic findings are considered together.