Congenital hypophosphatasia is a lethal short-limb dwarfism characterized by underossification of the bony skeleton, low serum alkaline phosphatase, and high urine phosphoethanolamine. This lethal dwarfism represents the most severe form of hypophosphatasia,1-3 All cases of hypophosphatasia are autosomal recessive, but there is a wide variation in severity, even within the same family.1 Levels of alkaline phosphatase in the amniotic fluid are variable and cannot be reliably used to diagnose this condition. 4 The prenatal sonographic diagnosis of hypophosphatasia has been reported at least six times previously, 4 -9 but in these cases there was a history of other family members with hypophosphatasia and the diagnoses rested on nonspecific findings of underossification of the skull and of limb shortening. We will report a case of congenital hypophosphatasia that we were able to confidently diagnose sonographically without a family history of the condition. CASE REPORTThe patient was a 16-year-old white female, gravida 1, para 0, abortus Q who conceived from consanguineous union. Review of the family history showed no previous genetic abnormalities.A sonogram performed at 27 weeks by menstrual dates, demonstrated a fetus consistent with a biparietal diameter of 7.8 em (31.3 weeks), a head circumference of 28.4 em (313 weeks), and an abdominal circumference of 25.6 em (297 weeks). The femoral lengths were t7 em (14.5 weeks) and t9 ern (15.1 weeks); humeral lengths were 2.3 em (167 weeks) and t9 em (152 weeks); and ulnar length was t9 ern (16.1 weeks). The skull was underossified; underossification was also noted in the facial bones, ribs, and limb bones (Fig. lA). The metacar· pal bones (Fig 18), neural arches of the spine (Fig. 2), and some of the vertebral bodies (Fig. 3) were unossified. These findings were considered diagnostic for hypophosphatasia.On delivery at term, radiographs (Fig. 4) and a low serum alkaline phosphatase (5 UfL, normal range of 37 to 132 U/L) confirmed the ultrasound diagnosis of hypophosphatasia. DISCUSSIONThe sonographic diagnosis of congenital hypophosphatasia in this case was based on the combination of (1) general underossification of the bones of the fetus, (2) limb shortening, (3) lack of ossification of groups of vertebral bodies, (4) lack of ossification of the neural arches of the spine, and (5) lack of ossification of the hands. The last three of these findings have not to our knowledge been described sonographically before and are based on previous radiographic observations. 1 - 3.5· 10Other frequently described radiographic observations, such as large metaphyseal areas in long bones that are poorly ossified in a ragged manner. 1 -3 ·u are not a major feature in our case and the sonographic appearance of such lesions has not been established. In our case, the skull and ribs appeared better ossified sonographically Received March 21. 1989, from the Department of Diagnostic Ultrathan radiographically.sound, Loma

The kidney is one of the most common organs in which cysts develop. A wide variety of renal diseases may have cysts of the kidney associated with them, including hereditary, developmental, and acquired disorders. Renal cysts may arise from any part of the nephron or the collecting tubule and may be located in the cortex, medulla, or both. Classification is often difficult, because the cysts often resemble one another. Sonography has become increasingly useful in the diagnosis of pediatric renal cystic disease and in evaluation of fetal renal abnormalities in utero and can help narrow the differential diagnosis.

Thanatophoric dwarfism is the most common form of lethal skeletal dysplasia and accounts for one of 246 perinatal deaths. The obstetric ultrasound examination is a primary diagnostic tool in the antenatal detection of thanatophoric dwarfism. Characteristic findings include thickened, shortened, and bowed extremities, a small, narrow thorax, flattened vertebral bodies with wide intervertebral disk spaces, and enlarged calvarium which may include cloverleaf skull deformity, pronounced skin thickening, and characteristic facies. In addition, polyhydramnios and nonimmune hydrops are occasionally seen with this entity. Sonographic features of this disease may allow its identification at an early fetal age. The obstetric sonographic examination, when combined with radiography, is definitive for diagnosis of thanatophoric dwarfism and can have a major impact on clinical management.

Conjoined twins have an incidence of about 1 in every 50,000 to 100,000 births., Ultrasound can play a major role in identifying and assessing conjoined twins as well as determining the degree of fusion between the fetuses. Another complication arises when a normal third fetus is present with the conjoined twins. We present a rare case of conjoined twins in a triplet pregnancy diagnosed prenatally with ultrasound. SONOGRAPHIC FINDINGSA 19-year-old white woman (gravida 2, para 1, abortion) was referred to our medical center from another facility. Sonographic evaluation was requested for fetal age and suspected abnormalities in a multiple gestation with the possibility of conjoined twins in the upper sac.Real-time ultrasound demonstrated a well-defined septum coursing between the two gestational sacs. The placenta was located posteriorly in the lower sac and anteriorly in the upper sac. Both placentas appeared normal in size and thickness.The lower sac contained a normal-appearing fetus in a transverse lie. Ultrasound measurements were consistent with approximately 17 menstrual weeks, and normal amniotic fluid volume was present.Conjoined twins were noted in the upper gestational sac in a transverse lie with a fused and irregularly shaped head. The head was increased in transverse diameter and two small orbits were noted as well as at least one ear in an abnormal position. There was a midline falx or septum with two widely separated areas of choroid plexus. Only one posterior fossa was evident. Two spines terminated at the common head (Fig. 1). Fusion was noted at the level of the abdomen and chest with separate pelves. There appeared to be a common liver. A single four-chamber heart with a normal rate and rhythm was noted in the right side of one fetus. The stomachs were not definitely seen; however, both urinary bladders were identified (Fig. 2). There were four lower extremities, including four feet, and four upper extremities, probably including four hands. No spinal defects were evident. The amniotic fluid volume was slightly increased in the upper sac.All three fetuses were male.The pregnancy was terminated, and gross pathologic and radiologic examinations were performed. The report from pathology described the following: 1. A normal-appearing male fetus that weighed 201 g and measured 21.5 cm in length 2. Male cephalothorocopagus twins that weighed 248 and measured 17.5 cm in length (Fig. 3)

Acute appendicitis is the most common cause of emergency abdominal surgery. A review of recent literature utilizing sonography for evaluation of appendicitis demonstrates a range of specificity from 95% to 100% and sensitivity of 80% to 89%. Using sonography to assess a patient for appendicitis may assist in differentiating this entity from an ovulating patient thus reducing false-positive surgeries.