The incidence of metastases from primary adenocarcinoma of the rectum in lymph nodes smaller than 5 mm is not known. Lymph nodes measuring less than or equal to 5 mm usually are not detected by manual techniques of examination of the surgical specimen. This retrospective analysis describes the results when a lymph node clearing technique that identifies lymph nodes as small as 1 mm was used to treat surgical specimens from 27 consecutive patients with rectal adenocarcinoma who underwent abdominoperineal resection with a curative intent and for whom all pathologic data were retrievable. Nine hundred thirty lymph nodes were found, with an average of 34 lymph nodes per specimen (range 0-88). Seventy-two of the 345 lymph nodes found in patients with Dukes C tumors were found to have metastases. Fifty-six (78 percent) of these 72 lymph node metastases occurred in lymph nodes measuring less than or equal to 5 mm. Three lymph node metastases were found in the perianal zone, 53 in the perirectal zone, and 16 in the pericolonic zone. Lymph node metastases from rectal adenocarcinomas often will occur in lymph nodes smaller than 5 mm. We concluded that the use of lymph node clearing techniques discovers these metastases, thereby offering the potential for enhanced staging of primary rectal adenocarcinomas.

An absent or hypoplastic nasal bone as a marker of trisomy 21 has been widely reported in both the first and second trimesters. A mid sagittal view of the fetal profile on two-dimensional (2D) ultrasound is the optimal view for assessment of the nasal bone. However, an off-axis view can result in the false impression of a nasal bone by imaging the adjacent maxilla. Use of three dimensional (3D) volume ultrasound rendered imaging can permit more accurate evaluation of the nasal bone, especially when a mid sagittal view is difficult to obtain. We present a case of absent nasal bone in the second trimester in a fetus with trisomy 21 in which 2D imaging mistakenly suggested the presence of a nasal bone, whereas 3D imaging with surface rendering resulted in the correct diagnosis of an absent nasal bone. A 31 year old Gravida 3, Para 1 woman was referred for a second trimester fetal survey at 18 weeks 3 days gestation with no prior screening. The scan was interpreted as normal with the exception of an echogenic intracardiac focus. The nasal bone was thought to be visualized by a sonographer and the interpreting physician. As part of our protocol a 3D volume of the face was also acquired and was subsequently evaluated by a second physician following completion of the exam. Surface rendered coronal views of the face suggested absence of the nasal bone. The patient elected to undergo a second trimester serum screen ('quad' screen) which resulted in a calculated risk of 1 : 653 for trisomy 21, which was similar to her age-related risk. The patient returned one week later for a follow up evaluation and at that time both 2D and 3D volume imaging confirmed the absence of a nasal bone. The patient underwent genetic amniocentesis based on this information, yielding trisomy 21. We conclude that 3D volume imaging with surface rendering in the coronal plane may be more accurate than 2D imaging alone for determining whether a nasal bone is absent. P09.15 Caudal regression syndrome: a case reportA. Soria, J. Iglesias, G. Villagomez Martinez, G. Castillo, J. Villarreal, R. Ambriz, G. Treviño Martinez Medicina Materno Fetal, Hospital Universitario Dr Jose Eleuterio Gonzalez, Monterrey N. L., MexicoCaudal regression syndrome (CRS) is a rare and sporadic disorder. This may result in various types of anorectal malformations, agenesis of spinal segments (sacral or lumbosacral). In the most severe cases, the lower limbs are fused (sirenomelia). Incidence is estimated 1 : 10000-60,000 live births; male:female ratio 2.7 : 1. Etiology and pathogenic mechanisms are poorly understood, but maternal diabetes, genetic predisposition and vascular hypoperfusion have been proposed. Case report: 25 years old woman, G3 P2 (history of macrosomic), first-degree relatives with diabetes mellitus type 2; attend to 1 th occasion antenatal control taking a course in 18 weeks; accomplishing ultrasound of routine where we observed absence of sacrum, fusion of lumbar vertebrae, bilateral talipes. Diagnosis of gestational diabetes was made. We conclude a caudal ...

This paper presents an overview of recent developments pertaining to colorectal adenocarcinoma. It is aimed toward the practicing clinician. Topics discussed include epidemiologic observations; genetic predispositions; molecular biology findings; screening and early detection programs; endoscopy; principles of surgical resection; laser and radioimmunoguided surgery; staging; selection of patients for adjuvant chemotherapy; and considerations regarding biologic response modifiers and pain control in the advanced-disease setting.

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