p53 Protein and Proliferating Cell Nuclear Antigen (PCNA) Expression in Small Round Cell Tumors of Bone and Adjacent Soft Tissue

Sixty small cell tumors of bone and adjacent soft tissue were studied in an attempt to define the incidence of immunohistochemically detectable p53 protein and cor relate these findings with the results of proliferating cell nuclear antigen (PCNA) immunohistochemical staining and mitotic counts. All of the lesions had been for malin-fixed and paraffin-embedded; half were subjected to decalcification prior to processing. The study population included 12 Ewing's sarcomas of bone, 3 atypical Ewing's sarcomas of bone, 3 primitive neuroectodermal tumors of bone, 11 Askin tumors of the thoracopulmonary region, 11 small cell osteosarcomas of bone, 10 mesenchymal chondrosarcomas of bone, and 10 malignant lymphomas involving bone. The patients ranged in age at the time of presentation from 17 to 67 years. Overall, the incidence of p53 positivity was extremely low in these lesions, irre spective of tumor type. Positive nuclear staining with an antibody to p53 was found in none of the 12 Ewing's sarcomas, none of the 3 atypical Ewing's sarcomas, none of the 3 primitive neuroectodermal tumors of bone, 1 of the 11 Askin tumors of the thoracopulmonary region (1.5% of tumor cells positive), 1 of the 11 small cell osteosarcomas (2% of tumor cells positive), 1 of the 10 mesenchymal chondrosar comas of bone (7% of tumor cells positive), and 2 of the 10 malignant lymphomas involving bone (0.5% and 1% of tumor cells positive, respectively). The majority of tumors showed PCNA positivity within the tumor cells, although the incidence of PCNA positivity within the histologic types varied greatly; in general, the higher PCNA counts corresponded to higher mitotic counts within the individual lesions. The present study did not demonstrate any correlation between mutant p53 accu mulation detected by immunohistochemistry and tumor type, and so it is unlikely that p53 positivity will prove to be of great use in the differential diagnosis of these lesions. A correlation between p53 positivity and PCNA staining or mitotic activity was not apparent. Int J Surg Pathol 2(4):259-268, 1995

Non-destructive studies of tissue-engineered phalanges by magnetic resonance microscopy and X-ray microtomography

One of the intents of tissue engineering is to fabricate biological materials for the augmentation or replacement of impaired, damaged, or diseased human tissue. In this context, novel models of the human phalanges have been developed recently through suturing of polymer scaffolds supporting osteoblasts, chondrocytes, and tenocytes to mimic bone, cartilage, and tendon, respectively. Characterization of the model constructs has been accomplished previously through histological and biochemical means, both of which are necessarily destructive to the constructs. This report describes the application of two complementary, non-destructive, non-invasive techniques, magnetic resonance microscopy (MRM) and X-ray microtomography (XMT or quantitative computed tomography), to evaluate the spatial and temporal growth and developmental status of tissue elements within tissue-engineered constructs obtained after 10 and 38 weeks of implantation in athymic (nude) mice. These two times represent respective points at which model middle phalanges are comprised principally of organic components while being largely unmineralized and later become increasingly more mineralized. The spatial distribution of mineralized deposits within intact constructs was readily detected by XMT (qCT) and was comparable to low intensity zones observed on MRM hydration maps. Moreover, the MRM-derived hydration values for mineralized zones were inversely correlated with mineral densities measured by XMT. In addition, the MRM method successfully mapped fat deposits, collagenous tissues, and the hydration state of the soft tissue elements comprising the specimens. These results support the application of non-destructive, non-invasive, quantitative MRM and XMT for the evaluation of constituent tissue elements within complex constructs of engineered implants.

Villonodular synovitis (PVNS) of the spine

OBJECTIVE

To describe the imaging features of spinal pigmented villonodular synovitis (PVNS).

DESIGN AND PATIENTS

We retrospectively reviewed 15 cases of pathologically proven spinal PVNS. Patient demographics and clinical presentation were reviewed. Radiologic studies were evaluated by consensus of two musculoskeletal radiologists for spinal location, spinal segments affected, lesion center, detection of facet origin and intrinsic characteristics on radiography (n=11), myelography (n=7), CT (n=6) and MR imaging (n=6).

RESULTS

Women (64%) were more commonly affected than men (36%) with an average age of 28 years. Clinical symptoms were pain (45%), neurologic (9%) or both (36%). Lesions most frequently affected the cervical spine (53%) followed by the thoracic (27%) and lumbar regions (20%). The majority of lesions (93%) were centered in the posterior elements with frequent involvement of the pedicle (67%), neural foramina (73%), lamina (67%) and facets (93%). No lesions showed calcification. Determination of a facet origin by imaging was dependent on imaging modality and lesion size. A facet origin could be determined in 45% of cases by radiography vs 67% of patients by CT (n=6) and MR (n=6). Large lesions (greater than 3 cm in at least one dimension) obscured the facet origin in all cases with CT and/or MR imaging (44%,n=4). Small lesions (less than 3 cm in any dimension) demonstrated an obvious facet origin in all cases by CT and/or MR imaging (56%,n=5). Low-to-intermediate signal intensity was seen in all cases on T2-weighted MR images resulting from hemosiderin deposition with "blooming effect" in one case with gradient echo MR images.

CONCLUSIONS

PVNS of the spine is rare. Large lesions obscure the facet origin and simulate an aggressive intraosseous neoplasm. Patient age, a solitary noncystic lesion centered in the posterior elements, lack of mineralization and low-to-intermediate signal intensity on all MR pulse sequences may suggest the diagnosis in these cases. Small lesions demonstrate a facet origin on CT or MR imaging. This limits differential considerations to synovial-based lesions and additional features of a solitary focus, lack of underlying disease or systemic arthropathy, no calcification as well as low-to-intermediate signal intensity on all MR images should allow spinal PVNS to be suggested as the likely diagnosis.

Most osteomalacia-associated mesenchymal tumors are a single histopathologic entity: an analysis of 32 cases and a comprehensive review of the literature

Oncogenic osteomalacia (OO) is a rare paraneoplastic syndrome of osteomalacia due to phosphate wasting. The phosphaturic mesenchymal tumor (mixed connective tissue variant) (PMTMCT) is an extremely rare, distinctive tumor that is frequently associated with OO. Despite its association with OO, many PMTMCTs go unrecognized because they are erroneously diagnosed as other mesenchymal tumors. Expression of fibroblast growth factor-23 (FGF-23), a recently described protein putatively implicated in renal tubular phosphate loss, has been shown in a small number of mesenchymal tumors with known OO. The clinicopathological features of 32 mesenchymal tumors either with known OO (29) or with features suggestive of PMTMCT (3) were studied. Immunohistochemistry for cytokeratin, S-100, actin, desmin, CD34, and FGF-23 was performed. The patients (13 male, 19 female) ranged from 9 to 80 years in age (median 53 years). A long history of OO was common. The cases had been originally diagnosed as PMTMCT (15), hemangiopericytoma (HPC) (3), osteosarcoma (3), giant cell tumor (2), and other (9). The tumors occurred in a variety of soft tissue (21) and bone sites (11) and ranged from 1.7 to 14 cm. Twenty-four cases were classic PMTMCT with low cellularity, myxoid change, bland spindled cells, distinctive "grungy" calcified matrix, fat, HPC-like vessels, microcysts, hemorrhage, osteoclasts, and an incomplete rim of membranous ossification. Four of these benign-appearing PMTMCTs contained osteoid-like matrix. Three other PMTMCTs were hypercellular and cytologically atypical and were considered malignant. The 3 cases without known OO were histologically identical to the typical PMTMCT. Four cases did not resemble PMTMCT: 2 sinonasal HPC, 1 conventional HPC, and 1 sclerosing osteosarcoma. Three cases expressed actin; all other markers were negative. Expression of FGF-23 was seen in 17 of 21 cases by immunohistochemistry and in 2 of 2 cases by RT-PCR. Follow-up (25 cases, 6-348 months) indicated the following: 21 alive with no evidence of disease and with normal serum chemistry, 4 alive with disease (1 malignant PMTMCT with lung metastases). We conclude that most cases of mesenchymal tumor-associated OO, both in the present series and in the reported literature, are due to PMTMCT. Improved recognition of their histologic spectrum, including the presence of bone or osteoid-like matrix in otherwise typical cases and the existence of malignant forms, should allow distinction from other mesenchymal tumors. Recognition of PMTMCT is critical, as complete resection cures intractable OO. Immunohistochemistry and RT-PCR for FGF-23 confirm the role of this protein in PMTMCT-associated OO.

Tenosynovial (extraarticular) chondromatosis: an analysis of 37 cases of an underrecognized clinicopathologic entity with a strong predilection for the hands and feet and a high local recurrence rate

Tenosynovial chondromatosis is a multinodular cartilaginous proliferation that arises from the tenosynovial membranes. This report describes the clinical, radiologic, and histopathologic findings in 37 cases of this uncommon entity. There were 17 males and 20 females, ranging in age from 20 to 86 years (mean and median age, 46 years). The process involved tenosynovium of the fingers (n = 19), feet (n = 8), wrists (n = 4), ankles (n = 2), hand, not otherwise specified, or palm (n = 2), knee (n = 1), and forearm (n = 1). Signs of disease or symptoms were present for 5 weeks to 18 years (median duration, approximately 2 years) before surgical excision. The two most common complaints were a painless mass and a mass that was mildly tender with pressure. None of the tumors had clinical, radiologic, or histopathologic evidence of articular or bone involvement. Histologically, all tumors consisted of a multinodular cartilaginous proliferation involving tenosynovium and/or subsynovial connective tissue. Mild or moderate atypia, as encountered in chondroma of soft parts and synovial chondromatosis, was a frequent finding. Follow-up information was available for 16 patients (43%). Only two patients with follow-up information remained disease free after their initial surgical procedure. Seven patients had one recurrence and seven patients had two or more recurrences. Tenosynovial chondromatosis appears to be an extraarticular counterpart of synovial (intraarticular) chondromatosis. Our review indicates this process is often confused with chondroma of soft parts, in part, because both entities have a predilection for the hands and feet. Diagnosis of this underrecognized entity is of clinical importance because of the high local recurrence rate.

Synovial-type giant cell tumors of the vertebral column: a clinicopathologic study of 15 cases, with a review of the literature and discussion of the differential diagnosis

Synovial and tenosynovial giant cell tumors only rarely arise in close proximity to the axial skeleton; to date, fewer than 30 examples have been reported in the English-language medical literature. In this report we describe the clinical, radiologic, histopathologic, and immunohistochemical findings in 15 cases retrieved from our files. The study group comprised 7 males and 8 females, ranging in age from 17 to 44 years (mean age, 32 years). The tumors involved the cervical (n = 11), thoracic (n = 1), lumbar (n = 2), and sacrococcygeal (n = 1) regions and ranged in size from 1.0 to 6.0 cm in greatest dimension (median size, 3 cm). Symptoms were present for 2 months to at least 2 years, with the most common complaint being pain localized to the spinal region (n = 12). Ten patients also had radicular symptoms. Radiologic studies, available for 11 cases, usually demonstrated a mass involving the posterior aspect of adjoining vertebrae. Bony abnormalities (including scalloping, erosion, and destruction), facet joint and soft tissue involvement, and extradural extension were typically present. Histologically, all tumors contained a proliferation of epithelioid (histiocytoid) cells, admixed with varying numbers of osteoclast-like giant cells, siderophages, xanthoma cells, lymphocytes, and some spindled fibroblast-like cells. Only 1 tumor had the classic villiform architecture of pigmented villonodular synovitis. The remaining 14 tumors had a nodular appearance with varying amounts of collagen. Seven of these had definite histological evidence of infiltrative growth, and 6 had some features that warranted concern for possible infiltration. Only 1 tumor had findings fully compatible with a localized synovial-type giant cell tumor/nodular (teno)synovitis. All tumors had mitotic activity, with mitotic counts ranging from 1 to 21 mitotic figures per 50 high-power fields (HPFs) (mean mitotic count, 5 mitotic figures/50 HPFs). Immunohistochemistry was performed on 5 tumors, and immunoreactivity was present for CD68, CD163, and vimentin. Limited immunoreactivity for muscle actin (HUC1-1) was also noted. Follow-up information was available for 9 of the 15 patients (60%). Five patients had no evidence of recurrent or persistent disease 4 months to 9 years after undergoing either a local excision with gross total tumor removal (with or without irradiation) or a wide en bloc resection. Four patients had persistent disease after undergoing either an incomplete resection or biopsy with spinal fusion procedure. All 4 of these patients had additional surgical intervention (accompanied by irradiation in 2 instances), but only one was known to be disease-free at last follow-up (10 years after gross total tumor removal). No patient has experienced a metastasis or died of disease. The best predictor of outcome was gross total tumor removal at the surgical outset.

Chondrosarcoma of the hand arising from a pre-existent benign solitary enchondroma

Chondrosarcomas of the hand are relatively rare. Chondrosarcomas may arise by malignant transformation of a pre-existing enchondroma, but this causal relationship has been difficult to establish in solitary enchondroma. This is a case report of a chondrosarcoma of the proximal phalanx of the right index finger in a 66-year-old woman demonstrating histologic evidence of malignant transformation of a pre-existent benign solitaary enchondroma. Careful analysis of the preoperative X-ray for punctate endosteal calcification or cortical expansion and ample histologic sampling of the endosteal component of chondrosarcomas arising from within bone may demonstrate a greater incidence of preexistent enchondroma.

Femoral neck stress fractures and metabolic bone disease

OBJECTIVE

To determine whether metabolic bone disease plays a role in the cause of femoral neck stress fractures.

STUDY DESIGN

Twenty-three patients with femoral neck stress fractures were enrolled prospectively in the study. Examination included computed tomography bone densitometry, trace mineral analysis, and histomorphometric analysis of the iliac crest in thirteen patients who underwent surgical treatment of their stress fractures. A control group of fifteen patients undergoing iliac crest bone grafting for scaphoid nonunions underwent similar examinations.

SETTING

Tertiary military medical center.

RESULTS

Patients with femoral neck stress fractures had lower bone mineral density than did control patients (p = 0.010), but no trace mineral deficiencies or consistent histomorphometric differences were noted.

CONCLUSIONS

Bone mineral density is decreased in patients with femoral neck stress fractures. Despite observations of decreased bone mineral density in the stress fracture group, osteoporosis, as determined by histomorphometry, is not a consistent finding.

Bone tumor dynamics: an orthopedic pathology perspective

The diagnosis and classification of primary bone tumors remains as much a challenge today as it has for the last 80 plus years. Although pathology is invariably equated with the image of a diagnostic microscope, the vast majority of diagnoses are made grossly with the unaided eye, as are the tissue specimens selected for microscopic "confirmation." Radiologic studies, particularly plain radiographs, remain the gold standard in gross pathologic diagnosis of the skeleton. Today, confirmation and final classification continue as the pathologist's domain, but perhaps not for long, considering the evolving ancillary imaging techniques and progressive sophistication of magnetic resonance (MR) imaging. The bone tumor cases collected and compiled by Ernest Codman, M.D. during the second through fourth decades of this century formed the basis of the first tumor registry. The Codman Bone Sarcoma Registry demonstrated among other things the importance of radiographic/pathologic correlation, underscoring the reliability of a bone tumor's location, margin (host bone/tumor interface), periosteal reaction, and matrix patterns as an accurate guide to classification and likely future biologic behavior. "A General Theory of Bone Tumors," written by Lent C. Johnson nearly 50 years ago and published in the Bulletin of The New York Academy of Medicine (February 1953, second series, vol. 29, no. 2, pp. 164-171), provided a conceptual cellular approach to the understanding bone tumor dynamics reinforcing radiologic/pathologic correlation as a reliable diagnostic tool. At the time of Dr. Lent C. Johnson's death (1910-1998), he was literally working on an updated version of his original article, the latter of which is being reprinted as the core of this illustrated revision. Our continued experience with bone tumors over the past five decades has only served to validate, on a daily basis, the fundamental principles outlined in Johnson's original article. In like fashion, it is important to keep in mind that terminology and nomenclature has also evolved since 1953, despite a continued inability to achieve complete consensus.

Liposclerosing myxofibrous tumor: a radiologic-pathologic-distinct fibro-osseous lesion of bone with a marked predilection for the intertrochanteric region of the femur

PURPOSE

To describe the characteristic features of liposclerosing myxofibrous tumor (LSMFT) of bone.

MATERIALS AND METHODS

The radiographs and clinical histories of 39 patients (21 male, 18 female; mean age, 42 years; age range, 15-69 years) with histologically verified LSMFT of bone were retrospectively studied.

RESULTS

LSMFT had a predilection for the proximal femur; more than 90% (30 of 33) of the femoral lesions were in the intertrochanteric region. Radiographs showed an indolent growth pattern with a well-defined and often extensively sclerotic margin. The bone contour either was normal or showed mild expansile remodeling. Mineralization within the lesion was not uncommon. Scintigrams showed mild to moderate focal tracer accumulation. Findings at computed tomography reflected those at radiography, whereas magnetic resonance imaging findings were nonspecific. Four (10%) patients had evidence of malignant transformation.

CONCLUSION

The radiologic appearance of LSMFT in the intertrochanteric region of the femur is characteristic. The substantial prevalence of malignant transformation associated with LSMFT underscores the need for close observation of this lesion.

Safety and pharmacokinetics of abacavir (1592U89) following oral administration of escalating single doses in human immunodeficiency virus type 1-infected adults

Abacavir (1592U89) is a nucleoside analog reverse transcriptase inhibitor that has been demonstrated to have selective activity against human immunodeficiency virus (HIV) in vitro and favorable safety profiles in mice and monkeys. A phase I study was conducted to evaluate the safety and pharmacokinetics of abacavir following oral administration of single escalating doses (100, 300, 600, 900, and 1,200 mg) to HIV-infected adults. In this double-blind, placebo-controlled study, subjects with baseline CD4+ cell counts ranging from < 50 to 713 cells per mm3 (median, 315 cells per mm3) were randomly assigned to receive abacavir (n = 12) or placebo (n = 6). The bioavailability of the caplet formulation relative to that of the oral solution was also assessed with the 300-mg dose. Abacavir was well tolerated by all subjects; mild to moderate asthenia, abdominal pain, headache, diarrhea, and dyspepsia were the most frequently reported adverse events, and these were not dose related. No significant clinical or laboratory abnormalities were observed throughout the study. All doses resulted in mean abacavir concentrations in plasma that exceeded the mean 50% inhibitory concentration (IC50) for clinical HIV isolates in vitro (0.07 microgram/ml) for almost 3 h. Abacavir was rapidly absorbed following oral administration, with the time to the peak concentration in plasma occurring at 1.0 to 1.7 h postdosing. Mean maximum concentrations in plasma (Cmax) and the area under the plasma concentration-time curve from time zero to infinity (AUC0-infinity) increased slightly more than proportionally from 100 to 600 mg (from 0.6 to 4.7 micrograms/ml for Cmax; from 1.0 to 15.7 micrograms.h/ml for AUC0-infinity) but increased proportionally from 600 to 1,200 mg (from 4.7 to 9.6 micrograms/ml for Cmax; from 15.7 to 32.8 micrograms.h/ml for AUC0-infinity. The elimination of abacavir from plasma was rapid, with an apparent elimination half-life of 0.9 to 1.7 h. Abacavir was well absorbed, with a relative bioavailability of the caplet formulation of 96% versus that of an oral solution (drug substance in water). In conclusion, this study showed that abacavir is safe and is well tolerated by HIV-infected subjects and demonstrated predictable pharmacokinetic characteristics when it was administered as single oral doses ranging from 100 to 1,200 mg.

Osteoblastoma of the foot and ankle

A total of 329 patients with osteoblastoma were retrospectively reviewed from the archives of the Armed Forces Institute of Pathology, of which 41 (12.5%) presented with tumors in the foot and ankle. This was the third most common site of disease after the spine and femur. Overall, the mean age was 22.5 years, which was the same for the foot and ankle subset of patients; however, there was a significant male predominance in foot and ankle patients compared with the whole group. The majority of patients were skeletally mature (85.4%). Clinically, most patients presented with pain (97.2%), although one-third of the total related a history of antecedent trauma. The interval between the onset of symptoms and biopsy was 84 days (range, 0-572 days). Radiographically, the majority of lesions were in the hindfoot (N = 18; 44%) of which 16 of 18 tumors (89%) were in the talus. Of these, one-half were subperiosteal and dorsally based and were associated with osseous tumor matrix and a soft tissue mass. Two osteoblastomas, both in the metatarsals, transitioned into sarcomas; the rest were histologically benign. For diagnostic purposes, it was essential to obtain clinical, radiographic, and histologic correlation.

Enchondroma versus chondrosarcoma in the appendicular skeleton: differentiating features

Distinction of enchondroma versus intramedullary chondrosarcoma affecting the appendicular skeleton (proximal to the metacarpals and metatarsals) is a frequent diagnostic dilemma. The authors studied a large series of patients with these lesions (92 with enchondromas, 95 with chondrosarcomas) using statistical assessment of both clinical parameters and numerous radiologic manifestations on images from multiple modalities to identify differentiating features. Multiple clinical and imaging parameters demonstrated statistically significant differences between enchondroma and chondrosarcoma, particularly pain related to the lesion, deep endosteal scalloping (greater than two-thirds of cortical thickness), cortical destruction and soft-tissue mass (at computed tomography or magnetic resonance imaging), periosteal reaction (at radiography), and marked uptake of radionuclide (greater than the anterior iliac crest) at bone scintigraphy. All of these features strongly suggested the diagnosis of chondrosarcoma. These criteria allow distinction of appendicular enchondroma and chondrosarcoma in at least 90% of cases.

Rectus femoris muscle tear appearing as a pseudotumor

Quadriceps muscle strains are common sporting injuries, but occasionally a tear of the rectus femoris muscle can appear as a soft tissue mass of the anterior thigh with or without a significant history of trauma. Between 1992 and 1996, seven patients were referred to the Orthopaedic Oncology Unit at Walter Reed Army Medical Center with an unexplained soft tissue mass of the thigh. Three were active duty soldiers, three were military dependents, and one was a retired serviceman. All patients were men, and the mean age was 32 years (range, 15 to 73). A palpable, mildly tender mass was confirmed on clinical examination. Laboratory studies and plain radiographs were normal. Magnetic resonance imaging showed an obvious, but often ill-defined, lesion at the musculotendinous junction of the rectus femoris muscle. Four patients subsequently underwent a tissue biopsy to rule out a soft tissue sarcoma. Histologic studies showed fibrosis, degeneration of muscle fibers, and chronic inflammatory cells with no evidence of malignancy. A chronic rectus femoris muscle tear can mimic a soft tissue tumor or sarcoma and needs to be excluded in the differential diagnosis. These tears may occur acutely or may represent an overuse injury caused by repeated microtrauma. Careful history taking, physical examination, and selective radiographic studies, specifically magnetic resonance imaging, can confirm the diagnosis of muscle tear and full functional recovery can be anticipated.

Focal myositis

Focal myositis is a pseudotumor of soft tissue that typically occurs in the deep soft tissue of the extremities, and is a relatively rare lesion. There is a wide clinical spectrum, with approximately one-third of patients with focal myositis subsequently developing polymyositis, and clinical symptoms of generalized weakness, fever, myalgia, and weight loss, with elevation of creatine phosphokinase. We report the case of a patient with focal myositis who subsequently developed myositis ossificans-like features.

Aneurysmal bone cyst: concept, controversy, clinical presentation, and imaging

The aneurysmal bone cyst is the result of a specific pathophysiologic change, which is probably the result of trauma or a tumor-induced anomalous vascular process. In approximately one third of cases, the preexisting lesion can be clearly identified. The most common of these is the giant cell tumor, which accounts for 19-39% of cases in which the preceding lesion is found. Other common precursor lesions include osteoblastoma, angioma, and chondroblastoma. Less common lesions include fibrous dysplasia, fibroxanthoma (nonossifying fibroma), chondromyxoid fibroma, solitary bone cyst, fibrous histiocytoma, eosinophilic granuloma, and even osteosarcoma. Interestingly, some of the controversy surrounding this lesion may be the result of a change in how the lesion was defined by Lichtenstein in 1953, when intramedullary lesions were added to the previously described juxtacortical (superficial) lesions. Members of the AFIP have suggested that many of the intramedullary lesions in which no previous lesion can be identified may represent giant cell tumors of bone. Their similarity to proved giant cell tumors in skeletally immature patients can be striking and seems more than coincidental. Appropriate treatment of an aneurysmal bone cyst requires the realization that it results from a specific pathophysiologic process, and identification of the preexisting lesion, if possible, is essential. Clearly an osteosarcoma with superimposed secondary aneurysmal bone cyst change must be treated as an osteosarcoma, and giant cell tumor with secondary features of aneurysmal bone cyst would be expected to be more likely to recur locally. The vast majority (approximately 80%) of patients presenting with aneurysmal bone cystlike findings are less than 20 years old. More than half of all such lesions occur in long bones, with approximately 12-30% of cases occurring in the spine. The pelvis accounts for about half of all flat bone lesions. Most patients present with pain and/or swelling, with symptoms usually present for less than 6 months. The imaging appearance of aneurysmal bone cyst reflects the underlying pathophysiologic change. Radiographs show an eccentric, lytic lesion with an expanded, remodeled "blown-out" or "ballooned" bony contour of the host bone, frequently with a delicate trabeculated appearance. Radiographs may rarely show flocculent densities within the lesion, which may mimic chondroid matrix. CT scanning will define the lesion and is especially valuable for those lesions located in areas in which the bony anatomy is complex, and which are not adequately evaluated by plain films. Fluid-fluid levels are common and may be seen on CT scans and MR images.(ABSTRACT TRUNCATED AT 250 WORDS)

MIC2 detection in tumors of bone and adjacent soft tissues

The diagnosis of Ewing's sarcoma has been based classically in large part on the exclusion of other similar small round-cell tumors by light microscopic and histochemical criteria. This study was undertaken to explore the use of a recently developed immunohistochemical stain directed against the glycoprotein p30/32MIC2 antigen (the gene product of MIC2), as a diagnostic tool and as a probe for the examination of potential interrelationships among the putative members of the family of peripheral primitive neuroectodermal tumors. Fifty-six small round-cell tumors of bone were selected for study from the files of the Armed Forces Institute of Pathology and Rhode Island Hospital; all tissues had been formalin fixed and paraffin embedded. Nine of 10 Ewing's sarcomas were MIC2 positive, as were 2 of 3 atypical Ewing's sarcomas (small round-cell tumors that diverged from the classic pattern of Ewing's sarcoma by exhibiting a greater degree of cytologic atypia and pleomorphism), and 7 of 8 Askin tumors of the thoracopulmonary region. Ten of 11 mesenchymal chondrosarcomas, 1 primitive neuroectodermal tumor of bone, 10 small cell osteosarcomas, 10 malignant lymphomas, and 3 sarcomas of bone (not additionally subclassified) were negative. The finding of MIC2 positivity in the majority of Ewing's sarcomas and Askin tumors provides additional support for earlier proposals (based on a shared cytogenetic abnormality, among other criteria) that these lesions be considered members of the same family, the peripheral primitive neuroectodermal tumors. The present study, drawing on archival and current case material (including decalcified and undecalcified specimens), indicates that neither the specimen age nor the application of any of a variety of decalcification solutions appears to adversely influence MIC2 staining of paraffin-embedded tissues. This suggests that this antibody has use in retrospective and prospective studies. The rare occurrence of false negative (in the case of Ewing's sarcoma) and positive results in tumors other than peripheral primitive neuroectodermal tumors (as in 1 of the mesenchymal chondrosarcomas) suggests that MIC2 staining should not be relied on as the sole criterion for identification or exclusion of Ewing's sarcomas and related tumors.

Oral and dermatologic manifestations of HIV infection

Because an estimated 1 million persons in the United States are infected with HIV, all physicians, especially those in primary care, need to be able to recognize the protean manifestations of the disease and make a diagnosis as early as possible. In this article, Drs Jewell and Sweet review the mucocutaneous conditions that occur in patients with HIV infection and discuss diagnostic clues and treatment.

An activating Gs alpha mutation is present in fibrous dysplasia of bone in the McCune-Albright syndrome

McCune-Albright syndrome (MAS) is a sporadic disease characterized by polyostotic fibrous dysplasia, café-au-lait spots, and multiple endocrinopathies. The etiology of fibrous dysplasia is unknown. Activating mutations of codon 201 in the gene encoding the alpha-subunit of Gs, the G-protein that stimulates adenylyl cyclase, have been found in all affected MAS tissues that have been studied. Initial attempts to amplify DNA from decalcified paraffin-embedded bone specimens from MAS patients were unsuccessful. Therefore, we analyzed DNA from frozen surgical bone specimens from five MAS patients using polymerase chain reaction and allele-specific oligonucleotide hybridization. Most of the cells in four specimens of dysplastic bone contained a heterozygous mutation encoding substitution of Arg201 of Gs alpha with His, but the mutation was barely detectable in peripheral blood specimens from the patients. Only a small amount of mutant allele was detected in a specimen of normal cortical bone from the fifth patient, although this patient had a high proportion of mutation in other, affected tissues. The mosaic distribution of mutant alleles is consistent with an embryological somatic cell mutation of the Gs alpha gene in MAS. The presence of an activating mutation of Gs alpha in osteoblastic progenitor cells may cause them to exhibit increased proliferation and abnormal differentiation, thereby producing the lesions of fibrous dysplasia.

Skeletal-extraskeletal angiomatosis. A clinicopathological study of fourteen patients and nosologic considerations

We reviewed the consultation files of the ARmed Forces Institute of Pathology for 1951 through 1989 and identified fourteen patients who had had skeletal-extraskeletal angiomatosis. Skeletal-extraskeletal angiomatosis was defined as a benign vascular proliferation involving the medullary cavity of bone and at least one other type of tissue. The age of the patients at the time of initial biopsy ranged from nine months to sixty-nine years (average, twenty-two years; median, ten years). Ten of the patients were male and four were female. The presenting signs and symptoms were highly variable; they included pain (four patients), a mass noted at birth (three patients), a painless mass that developed after birth (two patients), both pain and a mass (one patient), a localized deformity of the thoracic spine (one patient), and anemia associated with chronic bleeding of the gastrointestinal tract (one patient); in this last patient, skeletal lesions subsequently were found and biopsied. Skeletal-extraskeletal angiomatosis was an incidental finding in the remaining two patients. Multiple bones were involved in thirteen of the fourteen patients. Histologically, three patterns of lesion could be identified: cavernous lymphangioma (six patients), cavernous hemangioma (six patients), and arteriovenous hemangioma (two patients). Five of the patients died (three of sepsis associated with persistent lesions of angiomatosis and two of unrelated causes); eight of the patients survived but had residual disease, and one survived and had no evidence of residual disease.

Didanosine compared with continuation of zidovudine in HIV-infected patients with signs of clinical deterioration while receiving zidovudine. A randomized, double-blind clinical trial. The Bristol-Myers Squibb AI454-010 Study Group

OBJECTIVE

To determine the benefits of switching to didanosine compared with continuing zidovudine among patients infected with human immunodeficiency virus (HIV) who have previously used zidovudine and have signs of clinical deterioration.

DESIGN

Randomized, double-blind, two-armed, parallel, comparative clinical trial with a blinded, compassionate crossover provision at 12 weeks.

SETTING

Outpatient clinics at 19 tertiary care medical centers.

PATIENTS

312 patients infected with HIV who had received zidovudine for 6 months or more, had CD4 cell counts of 300/mm3 or less, and had signs of clinical deterioration within 12 weeks before study entry.

INTERVENTION

Peroral didanosine tablets (600 mg/d adjusted for weight, "high dose") or zidovudine capsules (600 mg/d).

MEASUREMENTS

Primary study end points were death, a new acquired immunodeficiency syndrome (AIDS)--defining event, or the combination of two new or recurrent HIV-related diagnoses with a 50% decrease in CD4 cells.

RESULTS

Switching to didanosine was associated with fewer end points than continuing zidovudine (relative risk [RR] for zidovudine:didanosine = 1.5; 95% Cl, 1.1 to 2.0). This benefit was consistent across subgroups of patients with either AIDS-related complex or AIDS and was most apparent among those with a CD4 count at entry of 100/mm3 or more (RR = 2.2; Cl, 1.1 to 4.4).

CONCLUSIONS

This study shows a positive treatment effect for switching from zidovudine to didanosine among patients with either AIDS-related complex or AIDS and validates the common practice of using clinical signs or a decrease in the CD4 count as an indication for changing therapy.

Surface-based hemangiomas of bone. A review of 11 cases

The surface-based hemangioma of bone is an uncommon cause of periosteal- or cortical-based lesions. The files of the Armed Forces Institute of Pathology were searched for lesions diagnosed as cortical hemangioma or periosteal hemangioma received between the years 1950 and 1990; 11 cases with follow-up results were identified. The 11 patients ranged in age from 11 to 31 years of age at the time of initial symptoms (average, 21 years; mean, 23 years). Sixty percent of the patients were male and 40% were female. Skeletal sites of involvement included the tibia (45%), the fibula (36%), the femur (9%), and the ulna (9%). Seventy percent of patients complained initially of pain (duration, two months to five years), whereas 30% reported pain and a mass at the time of initial diagnosis (duration, six months to two years). On plain film radiographs, eight lesions showed localized cortical thickening, two showed cortical erosion, and one had a permeative/destructive pattern. Bone scans showed solitary lesions with increased uptake in all 11 patients. The range of histologic types of cortical hemangioma included cavernous (six cases), arteriovenous (three cases), venous (one case), and pyogenic granuloma type (one case). Clinically, the majority of cases were diagnosed as osteoid osteomas; primary pathologic diagnoses included hemangioma (27%) and cortical sclerosis (18%). Persistent complaints were reported in three patients after intralesional biopsy; no recurrences were reported after en bloc excision.

Small cell osteosarcoma of bone: an immunohistochemical study with differential diagnostic considerations

Seventy-nine cases of small round cell tumors involving bone were studied in an attempt to learn whether the immunohistochemical features of the lesions might allow distinction of small cell osteosarcoma from other potential differential diagnostic considerations, including Ewing's sarcoma, atypical Ewing's sarcoma, primitive neuroectodermal tumor, mesenchymal chondrosarcoma, lymphoma, and the Askin tumor. The tissues studied were all formalin-fixed, decalcified, paraffin sections from patients between the ages of 16 and 48 years. With one exception (a small cell osteosarcoma), none of the lesions was cytokeratin positive. Moreover, none of the lesions was epithelial membrane antigen, desmin, factor VIII-related antigen, synaptophysin, or Leu-M1 positive. Accordingly, strong positivity for these antibodies in a majority of tumor cells should prompt inclusion of tumor types other than those listed above in the differential diagnosis. Vimentin positivity was seen in a majority of the tumors studied irrespective of histologic type. Scattered tumor cells (< 25%) showed positivity with antibodies to muscle-specific actin and smooth muscle actin in several of the different tumor types studied. No lesions other than lymphoma were leukocyte-common antigen (LCA) positive; all but two lymphomas were LCA positive, while all but one lymphoma were L26 positive. One (lymphoblastic) lymphoma was LCA and L26 negative. S-100, neuron-specific enolase, and Leu-7 did not prove to be specific for "neural-associated" tumors, but rather appeared in some small cell osteosarcomas, Ewing's sarcomas, atypical Ewing's sarcomas, primitive neuroectodermal tumors, mesenchymal chondrosarcomas, lymphomas, and Askin tumors. Antibody to cell surface antigen HBA71 was positive in three Ewing's sarcomas (two typical and one atypical) and negative in small cell osteosarcoma (three cases), mesenchymal chondrosarcoma (two cases), and lymphoma (one case). While some guidance may be derived from analysis of immunohistochemical staining patterns in a given lesion, the results reported in the present study do not suggest that routine immunohistochemistry alone will permit distinction of these small cell tumors of bone from one another. The value of immunohistochemical studies appears to lie particularly in the use of antibodies to LCA and S-100 protein to distinguish lymphoma and mesenchymal chondrosarcoma, and perhaps antibody to HBA71 to distinguish neural family lesions (such as Ewing's sarcoma), from other small cell tumors, such as small cell osteosarcoma.

Synovial hemangioma: a report of 20 cases with differential diagnostic considerations

True synovial-based hemangiomas are uncommon lesions and, as such, may enter the differential diagnosis of other lesions encountered more frequently in clinical practice, including pigmented villonodular synovitis and traumatic hemarthrosis. The consultation files of the Armed Forces Institute of Pathology were searched for benign vascular lesions diagnosed as synovial or bursal hemangiomas vascular lesions diagnosed as synovial or bursal hemangiomas submitted between the years 1960 and 1985; 20 cases of synovial hemangioma were identified. The patients ranged in age from 9 to 49 years at the time of presentation (average age, 25 years). Sixty-five percent of the patients were male; 35% were female. Presenting symptoms included pain and swelling (31%), pain alone (31%), and a painless mass (31%). Affected regions included the knee (60%), the elbow (30%), and the finger (10%). In 65% of cases the lesion was confined to the intra-articular synovium; in 30% of cases the hemangioma was located in a bursa adjacent to a joint. One case was located largely within the joint cavity but had an area of extension into the suprapatellar recess. The dominant histologic patterns included cavernous hemangioma (50%), lobular capillary hemangioma (25%), arteriovenous hemangioma (20%), and venous hemangioma (5%). One lesion (which had been incompletely excised) was removed in its entirety 3 months after the initial subtotal resection; otherwise, none of the patients studied developed recurrent disease. The clinical diagnosis of hemangioma was made in 22% of cases, while an initial pathologic diagnosis of hemangioma was reached in 67% of cases. Pathologic differential diagnostic considerations include nonspecific synovitis/bursitis, pigmented villonodular synovitis, nodular synovitis, and organizing hemorrhage. A relationship between synovial hemangioma and pigmented villonodular synovitis was not suggested by this analysis of our material.

Asymptomatic HIV infection. A primary care disease

Asymptomatic human immunodeficiency virus infection is a disease entering the primary care arena more and more frequently. Patients may be monitored in this setting until complications and clinical deterioration develop (typically after several years). As the disease progresses, referral to consultants who specialize in AIDS may be appropriate. However, many patients do not live near a major healthcare center and do not have the financial, physical, or emotional capability to travel to one as they become sicker. In these cases, primary care physicians, with the aid of a personally chosen network of specialized consultants, should offer care as the disease progresses to its terminal stage.

Parosteal lipomas: a new perspective

Parosteal lipomas, benign adipose tissue tumors situated directly on bone cortex, are unusual neoplasms that appear to emerge from multidirectional mesenchymal "modulation" within the periosteum. These tumors have been described as "periosteal lipomas", "chondrolipomas of soft tissue" and "lipomas of nerves" but they are most commonly believed to originate from the periosteum. Although over 100 of such tumors have been described in the literature, they have not been the subject of a comprehensive review, nor their potential for chondroid modulation and enchondral ossification emphasized. A review of 14 parosteal lipomas from the Bone Tumor Registry, Armed Forces Institute of Pathology, indicates these tumors are frequently associated with chondroid and/or osseous modulation, which permits subclassification into 4 distinct variants. Each of the 4 subtypes (I: No Ossification; II: Pedunculated Exostosis; III: Sessile Exostosis; IV: Patchy Chondro-Osseous Modulation) is illustrated to demonstrate the morphologic basis for radiologic/pathologic correlation and subclassification. A brief overview of the literature and pathogenesis of this unusual lesion is presented and discussed.

Giant cell tumor in skeletally immature patients

The radiographs and clinical and surgical histories of 50 skeletally immature patients with histologically verified giant cell tumor (GCT) of the long and short tubular bones were retrospectively studied to determine the prevalence, location within bone (eg, epiphysis, metaphysis), skeletal distribution, radiographic appearance, and pathogenesis of GCTs. Skeletal immaturity was determined radiographically by the presence of open epiphyses. Patients were selected from a group of 876 patients who were seen in consultation with documented GCT of the tubular bones. Approximately 5.7% of all GCTs occurred in the skeletally immature (this rate must be viewed with caution due to the selection bias inherent in any referral population). The lesions almost invariably involved the metaphysis. The tibia was the most commonly affected site, representing approximately 26% of cases. All were geographic lytic lesions, with margins ranging from sclerotic to ill defined. An expanded (widened), remodeled bone contour was frequently encountered. Approximately 56% of lesions were solid or solid with cystic change; the remaining 44% were predominantly cystic.

Cortical osteofibrous dysplasia of long bone and its relationship to adamantinoma. A clinicopathologic study of 30 cases

Thirty cases of cortical osteofibrous dysplasia (COFD) were studied in an attempt at defining the relationship of COFD to adamantinoma. The patients ranged in age from newborn to 39 years (mean 13.4 years). The male:female ratio was 1:1. Presenting symptoms were most often pain or a mass. The tibia was involved in all 30 patients; in addition, the ipsilateral fibula was involved in five patients (17%). The histologic appearance of the lesions was dominated by the combination of woven bone trabeculae with prominent osteoblastic rimming and a loose, slightly myxoid stroma (less heavily collagenized in most instances than usually encountered in intramedullary fibrous dysplasia). Results of immunohistochemical study showed isolated cytokeratin-positive cells in the stroma of 28 of the lesions (93%). However, hyperchromatic epithelial islands characteristic of adamantinoma were not found in any of the 30 cases. A control population of 50 fibro-osseous lesions (intramedullary fibrous dysplasia, sclerosing fibroxanthoma, and cranial ossifying fibroma) was studied immunohistochemically; in none of these control cases were cytokeratin-positive cells found. Follow-up data were obtained in 17 cases (57%); the period ranged from 1 to 16 years (mean 6.05 years). Certain overlapping clinical features (including the location of the vast majority of the lesions in the tibia and, less often, the fibula) and the morphologic similarities of many areas of COFD and adamantinoma (particularly the shared presence of cytokeratin-positive cells) suggest a more than coincidental association between COFD and a adamantinoma. However, to date none of the 30 cases of COFD evaluated in this study has developed an adamantinoma.

A histomorphologic and immunohistochemical study of chordoma in twenty ferrets (Mustela putorius furo)

The histomorphologic and immunohistochemical features of chordoma in 20 ferrets were evaluated. The mean age was 3.4 years, and, in the cases for which sex was known, females (n = 10) outnumbered males (n = 5) two to one. All 20 tumors occurred on the tip of the tail. Nineteen of 20 tumors (95%) were composed of three tissue components, often arranged concentrically with lobules of physaliferous cells at the periphery, trabecular bone in the center, and cartilage in between. The bone often contained marrow and hematopoietic cells. One tumor lacked chondromatous or osseous tissue. Immunohistochemical results were consistent with previous studies of chordoma. All 20 tumors (100%) were positive for keratin and vimentin intermediate filaments; 15 (75%) were positive for S-100 protein; and 17 (85%) were positive for neuron specific enolase. This neoplasm shares morphologic and immunohistochemical features with "classic," as well as chondroid chordoma, of human beings, making it a potential animal model.

Well-differentiated extraskeletal osteosarcoma. A soft-tissue homologue of parosteal osteosarcoma

We describe a unique case of a low-grade extraskeletal osteosarcoma revealing both histologic and radiologic features reminiscent of parosteal osteosarcoma. The tumor, which had been present for 10 years, occurred in the left axilla of a 74-year-old black woman. To date, all the published cases of extraskeletal osteosarcoma have been high-grade neoplasms; to our knowledge, this is the first reported case of a low-grade extraskeletal osteosarcoma.

John Caffey Award paper. Avascular necrosis: early MR imaging and histologic findings in a canine model

To examine the early MR and histologic changes of avascular necrosis, we surgically devascularized the distal femur of adult beagle dogs and performed short TR/short TE MR imaging and histologic examinations. MR showed increasing areas of low signal, and histologic examination showed changes of fat necrosis, inflammatory infiltrate, and fibrocytic and bony repair. These processes were divided into four stages. Stage 1 is seen in the first days after surgery and consists of homogeneous high signal on MR and only subtle histologic changes of early fat necrosis. Stage 2, seen by 7 days after surgery, shows linear low-signal areas within the high-signal marrow on MR and fat necrosis and an inflammatory infiltrate on histologic sections. Stage 3, seen by 16 days after surgery, shows patchy low signal occupying more of the marrow on MR with a fibrocytic infiltrate on histologic sections. Stage 4, seen by 23 days after surgery, shows a more homogeneous low and intermediate signal on MR and histologic findings of more organized fibrocytes and the onset of new bone formation. Using this model, we have proved that MR imaging can show marrow changes as soon as 1 week after the onset of avascular necrosis. Whereas MR imaging showed a progression of increasing areas of low signal, the histologic findings seen during this time were diverse, including inflammatory infiltration (a previously unreported finding), fat necrosis, and fibrocytic and osseous repair.

Osteosarcomatosis

A review of the 690 cases of osteosarcoma in the radiographic file of the Armed Forces Institute of Pathology revealed 29 cases of "osteosarcomatosis" (multiple skeletal sites of osteosarcoma). Fifteen of these patients were 18 years old and under and manifested rapidly appearing, usually symmetric, sclerotic metaphyseal lesions. The remaining 14 patients were more than 18 years old and had fewer, asymmetric sclerotic lesions. In most patients (28 of 29), a radiographically dominant skeletal tumor was seen. Pulmonary metastases occurred in the majority of patients and were detected at the same time as the bone lesions. These 29 patients were studied with regard to demographic data and skeletal distribution and radiographic appearance of their lesions. As a result of the findings, a metastatic origin from a primary dominant osteosarcoma is favored over a multifocal origin as the basis for osteosarcomatosis. Osteosarcomatosis is more commonly encountered in the mature skeleton than has been previously recognized.

Osteoid osteoma of the elbow. A review of six cases

Six cases of osteoid osteoma of the elbow were reviewed to determine the spectrum of clinical, pathologic and radiologic findings. Since osteoid osteoma of the elbow may masquerade as a nonspecific synovitis, the diagnosis is challenging and frequently delayed. The histology is, however, indistinguishable from that of osteoid osteoma occurring in typical locations. The radiologic features of osteoid osteoma of the elbow include the following triad: (a) osteosclerosis, usually a dominant feature at initial imaging and typically enveloping the nidus; (b) joint effusion; and (c) periosteal reaction that can involve both the bone in which the osteoid osteoma arises and adjacent bones. Awareness of these features will facilitate correct diagnosis, thereby facilitating timely and appropriate treatment.

Biphasic response of rat tibial growth to thyroxine administration

To evaluate the dose-response relationship between thyroxine and tibial growth, 60 male rats age 21 days were rendered hypothyroid by administration of methimazole in the drinking water. Twenty-one days later, the hypothyroid rats were randomly divided into 5 groups which received 0, 2, 8, 32, or 64 micrograms.kg-1.day-1 of T4 im for 21 days. All animals were sacrificed at age 64 days. Rat tibia were removed for measurement of epiphyseal growth plate width and longitudinal growth rate. Serum T4 and IGF-I levels were determined by RIA. Methimazole therapy significantly decreased serum T4, IGF-I, epiphyseal growth plate width, and longitudinal growth rate compared to controls. Epiphyseal growth plate width gradually increased when T4 was administered at doses from 2 to 32 micrograms.kg-1.day-1 (271 +/- 14, 311 +/- 15 and 324 +/- 11 microns), and subsequently decreased when T4 was given at a dose of 64 micrograms.kg-1.day-1 (267 +/- 8 microns). A similar profile was observed for longitudinal growth rate and IGF-I. We conclude that rat tibial growth has a biphasic response to exogenous T4 administration, and that the effects of T4 on tibial growth may be mediated through IGF-I secretion.

Radiology as gross pathology in evaluating chondroid lesions

The study of large ("whole mount") histologic sections underscores the complexity of bone lesions and explains the great potential for misdiagnosis when a limited biopsy sample is assumed to be totally representative. Diagnostic pitfalls can generally be avoided by insisting on the opportunity for clinical-radiologic-pathologic correlation ("triangulation") before a final diagnosis is made. Essential to the method of triangulation is equal attention to the three lines of evidence. The ability to render reliable, clinically relevant, and individually pertinent consultations (as opposed to purely histologic opinions) derives from pursuing questions until all lines of evidence point ("triangulate") to the same answer. This is especially true in the realm of cartilage tumors where the limitations of histopathology are widely acknowledged. In this review, the use of radiographic data will be explored in general terms and in the special context of chondroid lesions.

Direct administration of testosterone increases rat tibial epiphyseal growth plate width

Local injection of hormones into the tibial epiphyseal growth plate offers a possible model to answer whether sex steroids can affect bone growth directly. To answer this question, we injected different doses of testosterone enanthate (4, 40, 120 and 400 micrograms/100 g of rat weight) once into the tibial epiphyseal growth plate of castrated 35-day-old male rats. The contralateral tibia was injected with sesame oil and served as control. All animals were sacrificed at age 42 days. Tibias were removed for measurement of epiphyseal growth plate width and blood was collected for measurement of serum IGF-I and testosterone. The lower doses of testosterone enanthate (4, 40 and 120 micrograms/100 g) did not produce any significant change in epiphyseal growth plate width. Testosterone at the largest dose tested (400 micrograms/100 g) increased epiphyseal growth plate width by about 15% compared to control (p less than 0.01). At this dose, serum testosterone was not increased, suggesting that the effect on epiphyseal growth plate width was not due to higher systemic testosterone concentrations. No differences in IGF-I levels were observed among the groups. We conclude that direct administration of testosterone enanthate at a dose of 400 micrograms/100 g into the rat tibial epiphyseal growth plate can increase epiphyseal growth plate width.

Multiple sclerosis presenting as an intramedullary cervical cord tumor

We report a case of a 21-year-old white woman with a three-week history of rapidly progressive paresis and paresthesias of her extremities presenting as an intramedullary cervical cord lesion. Computer-assisted tomography and magnetic resonance imaging demonstrated a normal brain with a cervical cord enlargement suggestive of a primary spinal cord tumor. Her neurological deficits progressed despite dexamethasone; hence, laminectomy was performed with open biopsy of the cord lesion. The pathological specimens were sent to the Mayo Clinic and Kansas University for cell-type determination, due to their bizarre morphology. Both institutions concluded the biopsy specimens were demyelinated axonal plaques consistent with multiple sclerosis. This case illustrates that demyelinating disease can mimic spinal cord tumor, even with MRI scanning. Multiple sclerosis is a chronic demyelinating disease of the central nervous system. The clinical diagnosis requires documentation of lesions occurring on more than one occasion and at more than one site in the central nervous system. To improve the accuracy of the diagnosis of multiple sclerosis, spinal fluid analysis, visual and auditory evoked responses and radiologic imaging have been proposed. We report a patient with multiple sclerosis who presented with symptoms and physical findings suggesting a primary cervical cord tumor. Localized enlargement of the cervical cord was documented on magnetic resonance imaging. This is the first reported description of histopathologically confirmed spinal cord demyelination presenting as an intramedullary cervical cord tumor.

Comparison of heparin and 0.9% sodium chloride injection in the maintenance of indwelling intermittent i.v. devices

Heparin sodium 10 units/mL was compared with 0.9% sodium chloride injection as a flush solution for indwelling intermittent i.v. devices, or i.v. locks (IVLs), in a prospective, randomized, double-blind study. The heparin and 0.9% sodium chloride injections were prepared in the pharmacy using aseptic technique. Most of the IVLs were inserted by an i.v. therapy team member. Each patient's IVL site was evaluated for phlebitis and patency by one of three study nurses, and when a catheter was removed, its contents were flushed so that clots or fibrin strands could be detected. Nurses also collected information regarding disease states, surgical procedures, medications administered, and how long each site lasted. A total of 173 sites were studied in 76 patients in the heparin group, and 131 sites were studied in 71 patients in the sodium chloride group. The groups were well matched, except that the sodium chloride group received more vancomycin and dextrose-containing i.v. solutions, while the heparin group received more penicillins. There was no significant difference in the incidence of phlebitis or lost patency between the groups. When locks through which vancomycin, penicillins, and dextrose-containing i.v. solutions were administered were excluded, there was still no significant difference between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnesium toxicity secondary to catharsis during management of theophylline poisoning

Multiple doses of oral activated charcoal are used increasingly to promote elimination of toxins that have already reached the bloodstream; this is often referred to as gastrointestinal dialysis. Cathartics usually are used in conjunction to hasten transit of the charcoal-adsorbed toxin. In the present case, a regimen of activated charcoal and magnesium citrate was used to treat a patient with theophylline poisoning. It was effective in lowering the patient's serum theophylline concentration but produced an elevated magnesium level associated with decreased responsiveness, confusion, and diminished deep tendon reflexes. Magnesium citrate may not be the optimal cathartic for use in gastrointestinal dialysis, at least in selected patients. Sorbitol has been shown to produce a more rapid catharsis without disturbing magnesium serum concentrations. Therefore, the use of sorbitol in place of magnesium citrate, at least in selected patients, may be preferred.

Multiple skeletal fibroxanthomas: radiologic-pathologic correlation of 72 cases

Out of a series of 900 biopsy-proven cases of skeletal "fibroxanthoma" (nonossifying fibroma, fibrous cortical defect), we studied 72 patients with more than one lesion. Age, sex, coexistent conditions such as neurofibromatosis, and histologic and radiographic appearance of the lesions were evaluated. Multiple skeletal fibroxanthomas are probably more common than previously suspected. (At least 8% of the 900 patients in our archives had multiple lesions). Only a small percentage (5%) of patients with multiple skeletal fibroxanthomas had coexistent neurofibromatosis. These lesions are histologically indistinguishable from their solitary counterparts and most commonly present in the lower extremities. Four radiographic patterns were noted: clustered lesions--usually about the knee. nonclustered lesions--in opposite ends of long bones. coalescent lesions--several lesions coalescing over time. This observation has not been previously reported. emergent lesions--lesions appearing in previously unaffected bone. Familiarity with these features may obviate biopsy.

Epithelioid hemangioendothelioma and related lesions

Epithelioid hemangioendothelioma (EH) is the prototype of a group of vascular tumors characterized by an epithelioid or histiocytoid endothelial cell. This family also includes the epithelioid hemangioma (angiolymphoid hyperplasia with eosinophilia) and epithelioid forms of angiosarcoma. This review discusses the principal clinical, pathologic, and biologic differences among these three lesions. In particular the various manifestations of EH of soft tissue, bone, lung (previously called intravascular bronchioloalveolar tumor), and liver are discussed. Long-term follow-up data of EH of soft tissue and lung are provided.

Evaluation of H2O2 prophylaxis of bacteriuria in patients with long-term indwelling Foley catheters: a randomized controlled study

Since the long-term catheterized patient is at significant risk of urinary tract infection, and the catheter drainage bags of these patients are at significant risk of becoming reservoirs for nosocomial pathogens, we carried out a randomized, controlled study to determine the efficacy of intermittent drainage bag instillation of hydrogen peroxide (H2O2) in patients requiring indwelling Foley catheters for 5 days or more. Herein we report the effects of this technique on the rates of catheter and bag bacteriuria, the duration to positive culture, the temporal relationships observed, and the spectrum of organisms recovered. Bag source bacteriuria was found with the same frequency in both control and H2O2 groups. H2O2 did reduce contamination of the drainage bag but did not reduce catheter-associated bacteriuria or frequency of symptomatic urinary tract infection. Furthermore, H2O2 did not reduce the frequency of bag contamination with most of the common nosocomial urinary pathogens.