Edward P. Lin

Diagnostic clues to ectopic pregnancy.

Ectopic pregnancy accounts for approximately 2% of all pregnancies and is the most common cause of pregnancy-related mortality in the first trimester. Initial evaluation consists of hormonal assays and pelvic ultrasonography (US). A history of pelvic pain along with an abnormal beta human chorionic gonadotropin level should trigger an evaluation for an ectopic pregnancy. The fallopian tube is the most common location for an ectopic pregnancy. An adnexal mass that is separate from the ovary and the tubal ring sign are the most common findings of a tubal pregnancy. Other types of ectopic pregnancy include interstitial, cornual, ovarian, cervical, scar, intraabdominal, and heterotopic pregnancy. Interstitial pregnancy occurs when the gestational sac implants in the myometrial segment of the fallopian tube. Cornual pregnancy refers to the implantation of a blastocyst within the cornua of a bicornuate or septate uterus. An ovarian pregnancy occurs when an ovum is fertilized and is retained within the ovary. Cervical pregnancy results from an implantation within the endocervical canal. In a scar pregnancy, implantation takes place within the scar of a prior cesarean section. In an intraabdominal pregnancy, implantation occurs within the intraperitoneal cavity. Heterotopic pregnancy occurs when an intrauterine and an extrauterine pregnancy occur simultaneously. A spectrum of intra- and extrauterine findings may be seen on US images. Although many of the US findings are nonspecific by themselves, when several of them are seen, the specificity of US in depicting an ectopic pregnancy substantially improves.

The Importance of Monophasic Doppler Waveforms in the Common Femoral Vein A Retrospective Study

The purpose of this study was to assess the importance of monophasic waveforms encountered in the common femoral vein during deep venous thrombosis evaluation by a retrospective review of lower extremity venous Doppler (VD) sonography and correlative studies, such as computed tomography (CT) and magnetic resonance imaging.

Inflammatory pseudotumor of the kidney.

An inflammatory pseudotumor (IPT) is a rare entity that was originally described in the lung. 1 Inflammatory pseudotumors have been referred to as inflammatory myofibroblastic tumors, inflammatory pseudosarcomas or pseudosarcomatous myofibroblastic tumors, and atypical fibromyxoid tumors, among others. 2 Extrapulmonary IPTs have also been reported. The most common location in the genitourinary tract is the bladder. 3 A small number of case reports describe IPTs arising from the renal pelvis, the ureter, and, less commonly, the renal parenchyma. An IPT is a benign tumor that is often confused with malignancy. It is composed of spindle cells mixed with variable amounts of lymphocytes, plasma cells, proliferating myofibroblasts, and extracellular collagen. 4,5 Surgical resection is usually required for definitive diagnosis. Although early descriptions of this tumor described it as a reaction to an inflammatory and possibly infectious process, 4,6 the true pathogenesis of IPTs remains unclear. This report documents the course of the disease by imaging from presentation to complete resolution, without surgical resection.

Penile Schwannoma Sonographic Features

Benign and malignant tumors of the penis are uncommon. Benign lesions include leiomyoma, neurofibroma, condyloma acuminatum, schwannoma, bowenoid papulosis, lichen sclerosus, and Peyronie disease. 1-10 Most penile carcinomas are squamous cell. 11 They are located predominantly along the shaft, as opposed to benign lesions, which tend to occur near the glans penis.12 There are a number of case reports of penile schwannoma, but only a few describe the sonographic characteristics of lesions involving the penis. It is important to be familiar with the imaging features of penile tumors to assist in narrowing the differential diagnosis and in planning for potential elective surgery.

The “pool sign” of metastatic adenocarcinoma

The differential of a newly discovered solitary intracranial mass is a primary intracranial neoplasm and metastatic disease. Differentiating between the two entities on imaging is difficult, though there are clues on conventional imaging that suggest one over the other. The purpose of this article is to describe a new imaging finding on T2-weighted imaging, the “pool sign,” that may be specific for metastatic adenocarcinomas and can help differentiate a solitary metastasis from a primary CNS neoplasm. We present a series of four patients with initial magnetic resonance imaging of a solitary intracranial mass demonstrating the “pool sign,” and therefore predicted to be metastatic adenocarcinoma. All of these cases were confirmed to be metastatic adenocarcinoma on pathology.