Biomedical subjects
Publications and source records attributed to J X O'Connell.
Imaging plays a vital role in the diagnosis and management of synovial osteochondromatosis, a proliferative disorder of the synovium with associated loose body formation. The aim of this pictorial review is to illustrate the radiographic, computed tomographic and magnetic resonance appearances of various stages of the disease.
Pigmented villonodular synovitis is an uncommon proliferative disease of the synovium, which is usually monoarticular, presenting as chronic monoarthritis of the knee. To our knowledge, the case under discussion is only the second report in the English language medical literature of isolated involvement of the proximal tibiofibular joint.
We report a case of primary leiomyosarcoma of the distal femoral shaft arising in a patient who had undergone bilateral orbital enucleation for bilateral retinoblastoma several years previously. Radiography demonstrated an osteolytic, expansive lesion with cortical destruction anteriorly in the distal femoral shaft, and these findings were confirmed on CT. MR imaging revealed an expansive intramedullary lesion with cortical breakthrough and soft tissue extension. The occurrence of a second malignancy in patients with a history of bilateral retinoblastoma is well documented. Many different histological types have been described, with osteosarcoma and leiomyosarcoma occurring with the greatest frequency.
The purpose of this study was to review the imaging findings of three patients with bizarre parosteal osteochrondromatous proliferation of bone (BPOP). The plain radiographs and MRI images of three patients with BPOP were obtained and retrospectively reviewed. In two cases, BPOP involved the feet. In one case BPOP involved the hand. In all three cases, plain radiographs showed a well-defined calcium containing mass adjacent to the cortical surface of the adjacent bone. The underlying bone appeared normal in all cases. On MRI, the lesion was of low signal intensity on T1 weighted sequences in all cases. On FSE T2 weighted and STIR sequences, the lesion was of high signal in all cases. The cortex, medullary cavity and adjacent soft tissues appeared normal in all cases. While BPOP is rare and often confused with a variety of both benign and malignant lesions, there are specific radiological findings that may help to distinguish BPOP from many of its mimickers.
Skin tumours are usually divided into melanoma and non-melanoma types. Malignancies of the adnexal structures, of which sweat gland tumours are an example, are characterized under the non-melanoma types. Sweat gland malignancies are rare tumours that are usually associated with a poor prognosis. Given the rarity of these tumours, MRI findings of such tumours have not been described previously in the literature. We present a case report of an unusual malignant tumour of sweat gland origin known as a malignant chondroid syringoma of the skin with described MRI features. The MRI features are non-specific depicting intermediate signal intensity, changes on the proton density sequence and increased signal on the T2 and STIR-weighted sequences. Although these imaging features are characteristic of most soft tissue masses MRI can, in most cases, accurately depict the anatomic extent and identify tissue of origin, depth of invasion and relation to adjacent structures, such as muscles and bones. Thus high-resolution MRI of the skin in the future can be extremely helpful in characterizing and staging dermal neoplasms.
Soft-tissue chondromas are usually composed entirely of mature hyaline cartilage. Infrequently, however, they may exhibit morphologic features that result in diagnostic difficulty. The authors report a series of eight hypercellular soft-tissue chondromas composed of enlarged chondrocytes within a variable amount of chondroid matrix that often demonstrated delicate calcifications and contained numerous osteoclast-like multinucleated giant cells. This histologic appearance closely resembles that of chondroblastoma of bone. However, its extraosseous location, dense cellularity, and poorly formed cartilage can cause confusion with more aggressive chondroid neoplasms of soft tissue. The clinicopathologic features of these chondroblastoma-like chondromas are discussed, emphasizing the characteristics that facilitate their accurate identification.
Skeletal vascular tumors composed of epithelioid endothelial cells commonly result in diagnostic difficulty. Although tumors with this morphology have been recognized for many years, there is a considerable degree of confusion regarding their nomenclature and classification. In this article what is believed to represent the morphologic features of this family of tumors is outlined, the historical context of epithelioid endothelial tumors is briefly discussed, and pertinent literature and texts pertaining to the subject is reviewed. It is proposed that the osseous epithelioid endothelial tumors should be classified in a similar manner to their soft tissue counterparts and it is suggested that this approach should help to clarify the confusion surrounding this subject of surgical pathology.
Primary giant cell tumors (GCTs) of soft tissue resembling osseous GCTs are uncommon but distinct entities. Malignant GCTs of soft tissue have been designated giant cell malignant fibrous histiocytomas; however, there is scant data regarding benign GCTs of soft tissue. Eleven benign and seven malignant GCTs of soft tissue were identified from the authors' consultation files and the surgical pathology files of the Vancouver General Hospital and Massachusetts General Hospital. The tumors occurred in adults (eight men, 10 women; age range, 25-89 years; mean age, 54 years) in the extremities (n = 14) and in the trunk, abdomen, and pelvis (n = 4). In each patient the skeleton was normal and there was no history of prior osseous GCT. Tumors ranged in size from 0.8 to 9.0 cm. Eleven occurred in the superficial soft tissue and seven occurred in deep soft tissue. Grossly they were circumscribed and frequently hemorrhagic. Cystic change was present in seven tumors. Nine tumors were partially surrounded by a shell of reactive bone. In all tumors, multinucleated osteoclast-like giant cells were distributed uniformly and evenly among mononuclear cells. The histologically benign GCTs of soft tissue were identical to typical osseous GCTs. The mononuclear cells in these tumors lacked nuclear atypia or pleomorphism, and the mitotic rate within this population was low (mean, three mitoses per 10 high-power fields [HPF]). In the malignant GCTs of soft tissue, the mononuclear cells exhibited anisocytosis, nuclear atypia, pleomorphism, and readily detectable mitoses including atypical forms (mean, 25 mitoses per 10 HPF). None of the benign or malignant tumors exhibited neoplastic bone production. The benign and malignant GCTs of soft tissue demonstrated a similar immunohistochemical staining profile to GCT of bone ( 12 tumors examined), exhibiting strong positive staining for CD68 within multinucleated osteoclastlike cells, and focal staining of mononuclear cells for CD68, Ham 56, and smooth muscle actin. All tumors were treated by surgical resection. Follow-up information is available for 15 patients (range, 0-108 months). No benign tumor has recurred or metastasized. Of the four patients with malignant tumors for whom follow-up information is available, one died of metastatic disease at 13 months and one developed a local recurrence at 84 months but is alive, apparently free of disease after additional excisional surgery. Primary GCTs of soft tissue are distinctive neoplasms that, like osseous GCTs, exhibit a wide clinicopathologic spectrum. These neoplasms should be distinguished from other giant cell-rich soft-tissue tumors with which they may be confused.
STUDY DESIGN: A double-blind, prospective, randomized study using a validated rabbit model of intertransverse process fusion. OBJECTIVES: To determine the effect of stopping prolonged nicotine exposure on autogenous bone graft incorporation in a rabbit lumbar spinal fusion model. SUMMARY OF BACKGROUND DATA: There is a growing body of evidence that systemic nicotine impairs healing of spinal fusions and fractures. However, it remains to be determined whether, if nicotine increases the nonunion rate of spinal fusion surgery, stopping nicotine exposure before surgery will negate this inhibitory effect. METHODS: Forty-seven rabbits were divided into two experimental groups and one control group. The two experimental groups were exposed to systemic nicotine for 8 weeks. Nicotine exposure was stopped in one group 1 week before surgery; nicotine exposure was continued in the other group throughout the study. All rabbits underwent an L5-L6 intertransverse process fusion with autogenous iliac crest bone graft. All rabbits were killed 35 days after surgery. Forty rabbits completed the study and underwent radiographic, biomechanical, and histologic testing. RESULTS: Fusion, as determined by a blinded examiner palpating the spine, occurred in 7 of 13 control rabbits, 4 of 13 rabbits that "quit" nicotine, and none of the 14 rabbits exposed to continuous nicotine. There was a statistically significant difference between the control and continuous nicotine (P = 0.0015) and between the discontinued nicotine and continuous nicotine groups (P = 0.025). Biomechanical testing showed no significant differences between groups (P = 0.11). A blinded musculoskeletal pathologist was unable to detect a difference between groups based on histologic analysis. CONCLUSIONS: Chronic nicotine exposure was shown to decrease spinal fusion rates. Discontinuing nicotine before surgery improved fusion rates.
Misinterpretation of positive staining of antibodies to desmin, smooth muscle actin, and muscle actin as representing smooth muscle differentiation in the context of a spindle cell tumor is not uncommon. Anti-h-caldesmon is a promising novel immunohistochemical reagent for more specific smooth muscle differentiation. We studied 72 tumors (11 leiomyosarcomas, 26 malignant fibrous histiocytomas [MFHs], 11 fibromatoses, 11 cellular cutaneous fibrous histiocytomas [CCFHs], 5 malignant peripheral nerve sheath tumors, 4 synovial sarcomas, and 4 cases of nodular fasciitis), the reactive myofibroblastic response in 5 cases of acute cholecystitis, and the desmoplastic response surrounding 5 invasive breast carcinomas. Tissues were examined for expression of h-caldesmon, desmin, smooth muscle actin, and muscle actin. Diffuse staining for h-caldesmon was present only within the leiomyosarcomas. Focal staining for h-caldesmon involving less than 1% of lesional cells was present in 3 of 26 MFHs and 1 of 11 CCFHs. There was overlap in staining for the other "myoid" markers in all of the lesions that contained myofibroblasts. Anti-h-caldesmon seems to be a reliable marker of smooth muscle differentiation, and its inclusion in a panel of myoid immunohistochemical reagents should allow distinction of smooth muscle and myofibroblastic tumors.
Synovium is specialized mesenchymal tissue that is essential for the appropriate function of the locomotor apparatus. It is the site for a series of pathologic processes that are characteristic, and in some cases specific, to this distinctive tissue. In this article, the normal microscopic anatomy of synovium is briefly reviewed. Synovial proliferative disorders, including pigmented villonodular synovitis, giant cell tumor of tendon sheath, hemosiderotic synovitis, and fatty infiltration of the synovial membrane are discussed. Additionally, the subjects of intrasynovial cartilaginous lesions (primary and secondary synovial chondromatosis) and crystal deposition diseases are reviewed. Finally, the response of synovial tissues to implanted foreign materials that are used in large and small joint arthroplasty are described.
Differentiation of vascular abnormalities from soft tissue sarcomas may be difficult on clinical grounds, but is usually possible on imaging criteria. We report the MRI and digital subtraction angiography (DSA) findings in a patient presenting with a mass behind the knee. We discuss differentiating features and review the literature of similar cases.
Multiple hereditary osteochondromatosis is an uncommon autosomal dominant condition in which patients are predisposed to the development of chondrosarcoma. We report a case of a patient who developed a secondary low-grade chondrosarcoma in this setting. The tumor was associated with an unusual multinodular invasive growth pattern into a pre-existing bursa that was present overlying the osteochondroma.
A wide variety of common focal monoarticular synovial lesions may be encountered on imaging studies. A multi-modality approach to these lesions, with appreciation of the differing appearances, can often yield the correct diagnosis. This pictorial essay demonstrates and describes the imaging with illustration of pathologic findings in a spectrum of conditions.
A total of 202 revision hip arthroplasties in 178 patients, over a 2-year period, were evaluated prospectively. Intraoperative Gram stains were obtained from periprosthetic tissues in all cases. Of these, a definitive diagnosis of infection, using defined criteria, was established in 35 cases. Of these 35 patients, 17 had received antibiotics before surgery. The intraoperative cultures were positive in 8 of the 17 patients who had received antibiotics and 17 of the 18 patients who had not received preoperative antibiotics. In 1 infected case, intraoperative cultures of periprosthetic tissues failed to reveal bacterial growth, despite the fact that the patient received no preoperative antibiotics. Overall, there were 5 true-positive Gram stain results, 172 true-negative results, 3 false-positive results, and 22 false-negative results. The sensitivity of the Gram stain was 19%, specificity was 98%, predictive value of a positive test was 63%, and predictive value of a negative test was 89%. These results suggest that the intraoperative Gram stain is not a sensitive tool for the diagnosis of infection and should not be used when attempting to diagnose infection intraoperatively.
Although arthritis is often associated with synovial inflammation, the osseous changes in inflammatory and degenerative arthritis are principally reactive, and typically lack an acute inflammatory component. We have recently encountered several osteoarticular specimens removed at the time of large joint arthroplasty that have shown a distinctive pattern of subchondral acute inflammation (SCAI) resembling acute bacterial osteomyelitis. These microscopic findings heretofore have not been recognized as a component of the histopathology of arthritis. To determine the frequency of SCAI, we examined slides (mean four per case) from 164 hip arthroplasties performed at one of our institutions in a single year. A total of 10 cases of SCAI, including the 4 original examples (2 humeral head specimens, 2 femoral head specimens) and 6 identified from the slide review are described in this report. Eight patients were female and two were male (ages 54-86 years, mean 70, median 70). All had severe degenerative joint disease, six had rheumatoid arthritis, and three had osteonecrosis. In none was there a clinical or intraoperative suspicion of infection. Cultures of joint fluid or bone were not performed. In all cases, the inflammation was subchondral (within 1.0 cm of the joint surface), and it was frequently associated with subchondral cysts. In osteonecrotic foci, the suppurative inflammation was diffuse within the marrow space, whereas in viable bone it was nodular and vaguely granulomatous. Special stains for organisms were negative. None of the patients was treated with long-term IV antibiotics. There has been no septic loosening of the prostheses at follow-up intervals ranging from 5 to 36 months (mean: 17 months). Our observations, to the best of our knowledge, are novel. Although we cannot definitively exclude bacterial infection as a cause of SCAI, the histologic and clinical features suggest that SCAI likely represents a noninfectious sterile form of inflammation. Subchondral acute inflammation is possibly secondary to synovial fluid insudation into subchondral cancellous bone in the setting of severe osteoarthritis and/or rheumatoid arthritis.
We report the light microscopic, ultrastructural appearance and immunohistochemical staining profile of three distinctive soft-tissue tumors recently designated hyalinizing spindle cell tumor with giant rosettes. The tumors occurred in two men, 41 and 54 years old, and one woman, 62 years old. Two tumors arose in the lower extremities and one in the upper arm. Two tumors were resected and measured 3 and 13.2 cm in greatest diameter; a biopsy only was done of the third tumor. Grossly, the tumors had a tan, pink, or white cut surface. The largest tumor exhibited central cystic change. Microscopically, they all displayed similar features and were composed of fibromyxoid regions, with areas of hyalinization in two tumors and focal ossification in one tumor. Scattered throughout each of the tumors were rosette-like structures in which neoplastic cells were arranged around a central collagenous core. Ultrastructurally, the neoplastic cells demonstrated the features of fibroblasts. In all tumors, there was abundant extracellular collagen fibers and in one there were large aggregates of amorphous extracellular external lamina-like material. The center of the rosette-like structures was composed of banded collagen fibers and the cells at the periphery of the rosettes had ultrastructural features similar to the neoplastic spindle cells located elsewhere in the tumor. Immunohistochemically, the tumor cells stained for vimentin. There was focal staining of the widely distributed spindle cells and cells that formed the rosettes for Leu-7, S-100 protein, and CD34. In one tumor, there was faint diffuse staining of the spindle cells for neuron-specific enolase. One tumor (with the amorphous extracellular material) stained for type IV collagen. There was no staining for desmin, muscle actin, smooth muscle actin, keratin, or epithelial membrane antigen. These results demonstrate that hyalinizing spindle cell tumor with giant rosettes is composed of fibroblasts. We did not demonstrate any ultrastructural or immunohistochemical differences between the spindle cells that comprised the majority of the mass and those that surrounded the rosette-like structures. There was no ultrastructural evidence of neural differentiation to explain the focal S-100 protein and Leu-7 staining of the tumor cells.
BACKGROUND: Total hip arthroplasty is a commonly performed procedure in the United States and Canada that is associated with a definite risk of postoperative infection. Moreover, diagnosing an infection after total hip arthroplasty can present a challenge as there are no preoperative tests that are consistently sensitive and specific for infection in patients who need a revision arthroplasty. The present prospective study was performed to evaluate a variety of investigations for the diagnosis of infection at the site of a previous arthroplasty in order to determine if any combination of diagnostic studies could be used to determine which patients are at risk for a postoperative wound infection. METHODS: We prospectively analyzed the preoperative and intraoperative investigations used for the diagnosis of infection in 178 patients who had a total of 202 revision hip replacements. Clinical data were collected preoperatively. Investigations to determine the presence or absence of infection included a white blood-cell count, measurement of the erythrocyte sedimentation rate, measurement of the level of C-reactive protein, preoperative aspiration of the joint, intraoperative gram-staining and culture of periprosthetic tissue, a white blood-cell count in synovial fluid, and examination of intraoperative frozen sections. Frozen sections were analyzed in a blinded fashion without knowledge of clinical or laboratory data. Patients receiving antibiotics at the time of aspiration or collection of specimens for intraoperative culture were excluded from the analysis of those investigations, regardless of the results of the cultures. A positive result (suggestive of infection) was clearly defined for each of the investigations. RESULTS: Thirty-five hips (17 percent) were determined to be infected on the basis of clinical findings and positive results, according to the defined criteria, of investigations. With inflammatory conditions excluded, the sensitivity, specificity, positive predictive value, and negative predictive value were 0.82, 0.85, 0.58, and 0.95, respectively, for the erythrocyte sedimentation rate and 0.96, 0.92, 0.74, and 0.99, respectively, for the level of C-reactive protein. All patients who had a periprosthetic infection had an elevated erythrocyte sedimentation rate or level of C-reactive protein, but not always both. When patients who were receiving antibiotics were excluded, the results of aspiration of the joint were 0.86 for sensitivity, 0.94 for specificity, 0.67 for the positive predictive value, and 0.98 for the negative predictive value. Intraoperative studies revealed sensitivities, specificities, positive predictive values, and negative predictive values of 0.19, 0.98, 0.63, and 0.89, respectively, for gram-staining of specimens of the most inflamed-appearing tissue; 0.36, 0.99, 0.91, and 0.90, respectively, for the white bloodcell count in synovial fluid; and 0.89, 0.85, 0.52, and 0.98, respectively, for a neutrophil count in synovial fluid of more than 80 percent. The sensitivity, specificity, positive predictive value, and negative predictive value were 0.80, 0.94, 0.74, and 0.96, respectively, for the frozen sections and 0.94, 0.97, 0.77, and 0.99, respectively, for the intraoperative cultures. CONCLUSIONS: The combination of a normal erythrocyte sedimentation rate and C-reactive protein level is reliable for predicting the absence of infection. Aspiration should be used when the erythrocyte sedimentation rate or the C-reactive protein level is elevated or when a clinical suspicion of infection remains. We found the gram stain to be unreliable. Examination of intraoperative frozen sections is useful in equivocal cases or when hematological markers may be falsely elevated because of an inflammatory or other condition.