1314
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.“
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:.
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:,
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Pediatric
Case of the Day
John F. O’Connor,1 David J. Eschelman
Case
1: Ewing
Lisa
Sarcoma
C. Martin,
of Pubic
Henry
Chen,
Bonnie
L. Dobkin,
Bone
This i 5-year-old girl complained of intermittent left-sided groin pain for 2 years. She had no history of trauma, infection, or constitutional symptoms. Physical examination revealed fullness in the left inguinal region, but no discrete mass could be palpated. The plain radiograph of the pelvis (Fig. 1 A) revealed bony destruction of the left superior ramus and symphysis with a lamellated periosteal reaction. The bladder was displaced to the right by a large soft-tissue mass. A bone scan (Fig. 1 B) showed markedly increased uptake in the left superior and inferior rami, symphysis, and acetabulum. The extent of the tumor mass was then evaluated by MR imaging. Ti -weighted coronal (450/20) and axial (700/20) images (Figs. 1 C, 1 D, and 1 F) and T2-weighted axial (3000/80) images (Figs. 1 E and i G) showed a large soft-tissue mass encasing the left superior ramus with extension into the pelvis. The mass was isointense to muscle on Ti -weighted images and heterogeneously increased on T2-weighted images. Bladder wall invasion and bone marrow signal change in the left acetabulum were noted. An open biopsy was performed, and the histologic diagnosis was Ewing sarcoma. Ewing sarcoma is a malignant bone tumor usually seen in patients between the ages of 5 and 1 4, rarely seen in patients over the age of 30 [1 ]. Overall, it is the second most common primary malignant tumor of bone in children and accounts for 1 0% of all primary bone tumors. In the pelvic bones, it is the most common primary malignant tumor [2]. The cell of origin is unknown, but it is thought by some to arise from a stemcell precursor [3]. Clinically, there is a well-known delay in diagnosis. Patients will often have constitutional symptoms of malaise and fever with a leukocytosis suggesting an infection. When the pelvic bones are involved, poorly localized pain and a progressive limp are common [2]. Twenty percent of patients have metastases at the time of diagnosis, generally involving the lungs and other bones [4]. Plain radiography is the best imaging method for assessing the tumor and predicting the histologic diagnosis [1 5]. There are four types of radiographic changes: diffuse sclerosis, diffuse osteolysis, mixed sclerosis and osteolysis, and per,
,
All authors:
Department
AJR 156:1314-1320,
June
of Radiology,
Boston
University
1991 0361-803X/91/1566-1314
Medical
Center,
© American
meative osteolysis lated or sunburst, tumor
can
occur
Oliver
H. Pomeroy,
and
[2]. The peniosteal reaction may be larneland there may be a Codman’s triangle. The at any
skeletal
site,
occurring
more
often
in
the diarnetaphyseal region of long tubular bones in patients younger than 1 8 years old and in the flat bones in older patients
[i].
MR imaging is most useful in evaluating the extent of bone and soft-tissue involvement for preoperative and pretreatment planning [5]. The tumor is characteristically of decreased signal on Ti -weighted images and increased signal on T2weighted images [6]. After surgery or radiotherapy, a decreased signal on T2-weighted images has a high sensitivity for tumor sterilization. Continued increased signal on T2weighted images may indicate residual tumor, inflammatory changes from radiation, or postoperative hematoma. Gadopentetate dirneglumine induces a signal enhancement of both active tumor and inflammatory changes, adding little to longterm follow-up [5]. The differential diagnosis of this tumor should include osteomyelitis,
osteosarcorna,
eosinophihic
granulorna,
non-
Hodgkin lymphorna, and rnetastatic disease [2]. Survival rates have improved with aggressive adjunctive chemotherapy and megavoltage irradiation. The estimated 5year survival rate is currently 1 5%. The most important predictor of prognosis is the primary site. Primary tumors of the pelvic bone have the lowest survival rate [1]. Lisa C. Martin
REFERENCES 1 . Edeiken J, Dalinka M, Karasick D. Bone tumors and tumorlike conditions. In: Roentgen diagnosis of diseases of bone. Baltimore: Williams and Wilkins, 1990:395-421 2. Kozlowski K, Campbell J, Beluffi G, et al Primary bone tumors of the pelvis in childhood: Ewing’s sarcoma of the ilium, pubis and ischium. Austra/as Radiol i989;33 : 354-358 3. Remus W, Gilula L. Ewing’s sarcoma. In: Taveras J, Ferrucci J. Radiology, vol. 5. Philadelphia: Lippincott. i989;95:1-9 4. Simpson A, Bruner JM, Leavens ME. Metastatic Ewing’s sarcoma to the brain: case report and review of treatment. Surg Neurol 1989;31 :234-238 5. Frouge C, Vanel D, Coffre C, Couanet D, Cantesso G, Sarrazin D. The role of magnetic resonance imaging in the evaluation of Ewing Sarcoma. Skeletal Radiol 1988; 17 :387-392 6. Bloem J, Bluemm AG, Taminiau AHM, Van Oosterom AT, Stolk J, Doom-
88 E. Newton
Roentgen
Eric J. Sax,
St.
Ray Society
, Boston,
MA 021 1 8. Address
reprint
requests
to J. F. O’Connor.
PEDIATRIC
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AJR:156, June 1991
CASE
OF
THE
1315
DAY
..,-.
I 4d
C
f
‘7.
D
E
Fig. 1.-Case 1: Ewing sarcoma of the pubic bone. A, Anteroposterior radiograph of pelvis shows permeative bony destruction of left superior pubic ramus and symphysis with lamellated periosteal reaction. Bladder is displaced by a large soft-tissue mass. B, “Tc-methylene diphosphonate scintigram shows increased uptake in left superior and inferior pubic rami, symphysis, and acetabulum. c, Coronal Ti-weighted (450/20) MR image shows a large soft-tissue mass encasing left superior ramus with extension into pelvis. Bladder wall
invasion
is also seen.
D and F, Axial Ti-weighted E and G, Axial T2-weighted in left acetabulum.
(700/20) (3000/80)
bos J. Magnetic resonance imaging RadioGraphics i987;7:425-445
MR images MR images
of pelvis show that soft-tissue of pelvis show heterogeneously
of primary
malignant
bone
tumors.
mass is isointense increased signal
tion
of feedings. colon
transverse
feces mottled Case
2: Congenital
Colonic
Stenosis
After a normal delivery, a full-term girl passed rneconium and was discharged from the nursery. On day two she returned with abdominal distension, ernesis, and poor tolera-
to muscle. in soft-tissue
mass
and bone-marrow
A plain abdominal massively dilated
signal
changes
radiograph showed a to 6 cm and containing
with gas (Fig. 2A). There were gas-fluid levels on the upright abdominal radiograph (Fig. 2B) and on the cross-table lateral radiograph (Fig. 2C), which also revealed an abrupt caliber change in the sigmoid colon. A barium enema showed the sigmoid colon and rectum narrowed to less than 1 .5 cm (Fig. 2D). At the junction of the sigmoid and
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i 316
O’CONNOR
ET AL.
AJR:156,
June 1991
Fig. 2.-Case 2: Congenital colonic stenosis. A, Abdominal radiograph of supine patient shows severe colonic dilatation. Colon contains mottled feces and gas. B, Abdominal radiograph of upright patient shows marked colonic dilatation with gas-fluid levels. c, Cross-table lateral radiograph reveals dilatation of proximal colon and relative narrowing of sigmoid colon distal to stenosis. D, Barium enema shows a narrowed rectum and sigmoid colon. Colon is severely dilated proximal to congenital stenosis, located at junction of descending colon and sigmoid colon.
descending colon, a marked narrowing of 5 mm was encountered through which barium passed slowly. The differential diagnosis included colonic volvulus, congenital colonic stenosis, and Hirschsprung disease. During surgery on the third day after birth, a sharp transition in bowel diameter was identified, changing from 2.5 cm in the distal descending colon to 5 mm in the proximal sigmoid colon. There were several corkscrewlike vessels from aberrant mesenteric locations at this site. The distal bowel was markedly kinked and quite narrow in caliber. The stenotic segment was resected with 1 -cm margins, forming a Hartman pouch and a colostomy. Pathologic examination of the resected colon showed a 3-mm lumen at the stenosis. Ganghion
cells were present throughout the specimen, establishing the diagnosis of congenital colonic stenosis. The colon is the least common site of congenital intestinal stenosis and atresia. It accounts for 5-i 5% [1 ] of intestinal stenoses and atresias, occurring in one in 40,000 births [2]. The theory of incomplete recanahization [3] applies to the duodenum but not the more distal small and large bowel. It is thought that atresias in these regions are the result of a vascular insult in utero [4]. Multiple intestinal atresias may be the result of an in utero inflammatory process of the bowel of unknown origin [5]. Louw [4] classified atresias in three groups as follows: type 1 one or more septa or diaphragms occluding the lumen; type 2, proximal and distal blind ends ,
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joined by a threadlike structure, with or without a mesenteric defect; and type 3, proximal and distal blind ends that are completely separated with a V-shaped mesenteric defect. Patients present clinically with vomiting and progressive abdominal distension. Physical examination often reveals abdominal distension, palpable intestinal loops, and dehydration. With complete colonic atresia, failure to pass meconium and absence of meconium in the rectal vault are noted. In congenital stenosis, passage of meconium may occur. Abdominal radiographs show distended bowel with air-fluid levels. Rectal air may be absent in colonic atresias. A contrast enema typically demonstrates a small-caliber colon (microcoIon) distal to an atresia without proximal flow, or a narrow segment of stenotic colon in congenital stenosis. In type 3 atresias, a characteristic “hooking” of the contrast column proximal to where retrograde flow is halted has been described in association with “recoiling” of the proximal portion of the distal atretic segment, which is free by virtue of its mesenteric defect [6]. Early surgical resection is imperative. Lesions proximal to the splenic flexure are treated with resection of the dilated proximal segment and primary ileocolostomy. Lesions distal to the splenic flexure are usually treated with diverting loop colostomy followed by staged resection of the atretic or stenotic segment and subsequent restoration of colonic continuity. Complications may require a staged repair regardless of the site of obstruction [7]. EricJ. Sax
ACKNOWLEDGMENT
The author thanks Kerry Bergman for surgical
and pathologic
follow-up
of the Boston
Floating Hospital
in this case.
REFERENCES
1. Powell AW, Raffensperger i982;17:
JG. Congenital
colonic atresia. J Pediatr
Surg
gion,
163-1 64 EA Jr, ed. Gastrointestinal
2. Franken imaging in pediatrics, York: Harper Aow, 1982:286-287 3. Tandler J. Zur Entwicklungsgeschichte des menschlichen fruhen embryonalstadien. Morphol Jahrb i900;29: 187-216
2nd ed. New duodenum
in
4. Louw JH. Congenital intestinal atresia and stenosis in the newbom: observations on its pathogenesis and treatment. Ann R Coil Surg EngI 1959;25:209-234 5, Puri P, Fujimoto T. New observations on the pathogenesis of multiple intestinal atresias. J Pediatr Surg i988;23:221-225 6. Selke AC Jr, Jona J, The hook sign in type 3 colonic atresia. AJR i978;131 :350-351 7, Defore NW Jr, Garcia-Ainaldi A, Mattox KL, Harberg FJ. Surgical management of colon atresia. Surg Gynecol Obstet 1976:143:767-769
Case 3: Diffuse Aseptic Sickle Cell Disease
Bone
reaction in the metadiaphyseal segment of the long bones. Similar changes also were noted in the metacarpals and phalanges of the right hand. At this point, the differential diagnosis included bone infarction and osteornyehitis. Radionuchide studies, both a technetium bone scan (Fig. 3E) and gallium imaging (Fig. 3F), had inconclusive results. Open bone biopsies of the proximal tibiae showed aseptic bone infarction. When subjected to low oxygen tension, RBCs containing Hb SS become deformed into a sickle shape and block small blood vessels, preferentially at branching points, causing tissue ischemia and infarction if there is inadequate collateral circulation. In the neonate with Hb SS disease, the ABCs have a high concentration of fetal hemoglobin so that sickling does not occur. During the first year of life, Hb 55 gradually replaces the fetal hemoglobin, and tissue ischemia and infarction occur [1]. The main blood vessel to a long or short tubular bone is the nutrient artery that enters through the diaphyseal cortex, nourishing the medullary cavity and the inner portion of the cortex. Multiple periosteal vessels support the outer diaphyseal cortex. Both of these vascular sources must be comprornised before cortical infarction is produced. This occurs more readily in the very young, in whom the periosteum is loosely attached to the cortex and can easily be separated by inflammatory edema. Separate vessels supply the epiphysis and metaphysis [1]. The first ischemic manifestation of Hb SS is usually dactylitis, also known as hand-foot syndrome. This may appear any time after 3 months of age, but more often occurs at 6-i 8 months. It often recurs but is uncommon after age 6, when red marrow recedes from the tubular bones of the hands and feet. Radiographs may show only soft-tissue swelling or a fine periosteal reaction when infarction is confined to the medullary cavity. If periosteal circulation becomes compromised, diaphyseal cortical bone infarction results, with areas of bone destruction and patchy areas of new bone formation. The destruction may be confined to the metadiaphyseal re-
Infarcts
in a Child
with
This case involved a 1 5-month-old Nigerian girl with sickle cell disease (Hb SS) who was brought to the emergency department with fever. In the course of her evaluation, a chest radiograph (Fig. 3A) that was obtained to exclude pneumonia showed bilateral cortical destruction and periosteal reaction in the humeri. A complete radiographic bone survey (Figs. 36-3D) revealed symmetric abnormalities involving the long bones of the extremities. The findings consisted of cortical destruction, often full-thickness, and symmetric periosteal
or the entire
diaphysis
may
be involved.
The
epiphyses
and metaphyses are usually spared because of their separate blood supply [1]. In the young, long bones undergo acute infarction just as do the short tubular bones of the hands and feet. This usually begins a few years later and may occur in association with dactyhitis. When the long bone involvement is not severe, there may be no radiologic changes or only periosteal reaction. In these cases, infarction is confined primarily to the medullary cavity [1]. When involvement is more severe and the periosteal circulation is compromised, full thickness cortical destruction occurs. Single or layered periosteal reaction may be seen in association with cortical destruction. In children about 8 years old and older, the periosteurn is more firmly attached to the diaphyseal cortex, and it is more difficult to compromise the periosteal circulation of the outer portion of the cortex. Acute diaphyseal involvement in these children is usually limited to the medullary cavity and adjacent inner half of the cortex, with splitting of the cortex into necrotic bone centrally and viable bone peripherally. Eventually this process can result in a “bone-in-a-bone” or “tram line” appearance [1]. Bone infarcts tend to spare the metaphyses because of extensive collateral circulation in the region of the growth plate. In the young, the epiphyses are not commonly infarcted;
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.
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,
$ 7.
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AJR:156,
PEDIATRIC
June 1991
CASE
it is rare for them to be involved before the growth plate fuses. The classic site for long bone infarcts is the metadiaphyseal segment of the shaft. The rnetadiaphyseal location is helpful in distinguishing Hb 55 infarcts from primary hernatogenous osteomyehitis, which classically begins at the metaphysis [1 ]. Bilateral, symmetric involvement is very frequent in Africa, of moderate frequency in Jamaica, and less common in the United States [1]. The classic sign of Hb 55 in the spine is the H-shaped vertebra, which is virtually pathognomonic. In the skull, multiple episodes of infarction and periosteal reaction yield a distinctive
“hair-on-end”
appearance.
Coarse
granular
osteo-
penia and focal Iucencies also can be seen. Facial bone infarcts have been reported as well [2]. Infarcted bone is a fertile site for secondary infection. Furthermore, Hb SS patients have immunologic deficiencies, in part related to associated autosplenectomy. For these reasons, there is a high prevalence of secondary osteornyehitis at the site of acute bone infarcts. Staphylococcus aureus and Salmonella organisms are the most common offenders. Radiologically and clinically, septic infarcts and sterile infarcts may be indistinguishable. This is understandable, because the mechanism of bone destruction in both is avascular necrosis [1 ]. Radionuclide studies have been suggested as a good method for distinguishing septic from sterile infarcts. In this particular case, technetium-99m bone imaging and galhium-67 imaging were performed. In the study by Amundsen et al. [3], when osteomyehitis was present, 67Ga uptake was abnormally increased. Sterile infarction usually resulted in normal or decreased 67Ga uptake. However, when both 99mTc and 67Ga uptake were increased, the result was indeterminate. Our patient demonstrated this pattern, and a biopsy was necessary for diagnosis. The final diagnosis was aseptic bone infarction. Other radionuchide studies offer promise. 11n-labeled Ieukocytes and technetium-sulfur colloid bone marrow imaging have been studied in conjunction with bone and gallium scans, with reports of increased sensitivity and specificity [4-6]. MR imaging will undoubtedly play a greater role in the evaluation of Hb SS bone disease. Hen Chen ry
REFERENCES 1 . Bohrer
SP. Bone
Roentgenol
2. 3.
4,
5.
6.
Case
THE
DAY
i 3i 9
4: Neurocysticercosis
This 1 6-month-old girl, born in the United States to Cape Verdean parents, was brought to the emergency department with an afebrile generalized seizure. Unenhanced CT studies (Fig. 4A, top row) showed foci of decreased attenuation in the left parietal, left frontal, and right parietal lobes. A small focal calcification was noted in the left frontal and right parietal lesions. Contrast-enhanced CT (Fig. 4A, bottom row) showed enhancement of these lesions with associated surrounding edema. MR imaging (Figs. 4B and 4C) showed the calcifications as three foci of decreased signal in the subcortical gray/ white matter junction on T2-weighted (3000/90) images, surrounded by irregular areas of increased signal representing white matter edema. Serologic testing of serum and CSF were positive for cysticercosis. Ova of Taenia solium were isolated from the stool of the patient’s father. Neurocysticercosis represents infestation of the CNS by the pork tapeworm, Taenia solium, in its larval stage. Neurocysticercosis is most prevalent in less-developed countries; however, its prevalence in the United States is increasing because of the influx of immigrants from endemic areas [1]. Infection occurs by ingesting ova from undercooked pork or by the fecal-oral route from an infected host. The larvae penetrate the intestinal wall and are distributed hematogenously to multiple sites that include the CNS, muscle, skin, and heart. Once established in the target organ, the larval cells proliferate, eventually producing cysts 1 cm or less in size. A small invagination develops along one margin of the cyst and proliferates to become a scolex measuring 2-3 mm. Without treatment, the natural history is for the parasite to die in approximately 1 -5 years, resulting in cyst degeneration with a striking inflammatory and gliotic reaction in the host. Symptoms develop when cyst degeneration begins [2]. The end of the degenerative process is represented by cyst calcification. Clinical symptoms referable to CNS infection indude seizures, intracranial hypertension, focal neurologic deficits, and dementia. The diagnosis of neurocysticercosis may be made by either CSF or radiologic findings. Examination of the CSF may reveal nonspecific findings of pleocytosis, eosinophilia, protein elevation, and glucose depression. Serologic tests for cysticercosis can be performed by specialized laboratories such as the Centers for Disease Control. CT and MR imaging are the current imaging techniques of choice for the diagnosis of neurocysticercosis [1 3]. The CT changes reflect the natural history of the disease and may be used to distinguish between viable, dying, and dead cysticerci. Three patterns of neurocysticercosis, either alone or in cornbination, may be observed on CT scans [4]. The parenchyrnal form is the most common and may be acute or chronic [5]. The acute phase looks like encephalitis because of compression, destruction, or irritation of brain tissue. During this stage, low-density cysts, measuring 1 cm or less in diameter, may be visualized. The cysts display ring enhancement or contain hyperdense nodules and are often associated with surrounding edema. In the chronic phase, which may occur within 1 year of onset, the cysts die and calcify, showing hyperdense foci on unenhanced CT scans and areas of signal void on MR images. The second form consists of intraventricular cysts. ,
changes
in the extremities
in sickle
cell anemia.
Semin
i987;22: 176-1 85 Royal JE, Harris VJ, Sansi PK. Facial bone infarcts in sickle cell syndromes. Radiology i988;169:529-531 Amundsen TA, Siegel MJ, Siegel BA. Osteomyelitis and infarction in sickle cell hemoglobinopathies: differentiation by combined technetium and galhum scintigraphy. Radiology i984;1 53:807-812 Schauwecker DS, Park HM, Mock BH, et al. Evaluation of complicated osteomyelitis with Tc-99m MDP, In-i 1 1 granulocytes, and Ga-67 citrate. J NucI Med 1984:25:849-853 Kahn CK, Ryan JW, Hatfield MK, Martin WB. Combined bone marrow and gallium imaging: differentiation of osteomyelitis and infarction in sickle hemoglobinopathy. C/in NucI Med 1988;1 3:443-449 Rao 5, Solomon N, Miller 5, Dunn E. Scintigraphic differentiation of bone infarction from osteomyelitis in children with sickle cell disease. J Pediatr
i985;107:685-688
OF
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1320
O’CONNOR
ET AL.
AJA:156, June 1991
Fig. 4.-Case A, Unenhanced
low-attenuation
4: Neurocysticercosis. CT scans (fop row)
show
areas of edema in left parietal,
left frontal, and right parietal lobes. A small focal calcification is noted in left frontal and right parietallesions. Enhanced CT scans (bettorn row) show round, well-defined, enhancing foci within small areas of edema. B and C, Axial T2-weighted (3000/90) MR images of head reveal irregular areas of in-
creased signal representing white matter edema. Calcifications appear as well-defined foci of decreased signal.
These are asymptomatic unless there is obstruction to CSF flow, which may be fatal if onset is sudden, or result in intermittent intracranial hypertension. Finally, cysticerci within the subarachnoid space may be free-floating or adherent to the pia. Groups of cysts tend to aggregate in the basilar cisterns, forming structures up to several centimeters in diameter. These often produce a clinical picture of chronic aseptic meningitis. Neurocysticercosis is rare in infancy, and its presentation as new-onset seizures in this 1 6-month-old infant is another warning to the medical community that immigrant populations may have a surprisingly wide range of underlying abnorrnalities. The large numbers of imaging studies performed for new-onset seizures that have normal findings may be vindicated by finding such a rare and unusual cause of seizures. Therapy for neurocysticercosis may be surgical or medical. The ventricular form is treated either by resection of acces-
sible cysts or shunting. Medical treatment consists of antiparasitic medication, either alone or in combination with steroids and antiepileptics. Bonnie L. Dobkin Oliver H. Pomeroy
REFERENCES 1 , Teitelbaum G, Otto A, Lin M, et al. MA AJNR i989;10:709-718
imaging
of neurocysticercosis.
2. Shanley JD, Jordan MC. Clinical aspects of CNS cysticercosis. Med
Arch
Intern
1980:140:1309-1313
3, Suss A, Maravilla K, Thompson
J. MR imaging of intracranial cysticercosis:
comparison with CT and anatomopathologic features. AJNR i986;7: 235-242 4. Lotz J, Hewlett A, Alheit B, Bowen A. Neurocysticercosis: correlative pathomorphology and MR imaging. Neuroradiology i988;30:35-41 5. Mervis B, Lotz JW. Computed tomography (CT) in parenchymatous carebral cysticercosis. C/in Radiol 1980:31 :521-528