Melorheostosis: case report with radiologic-pathologic correlation.

Melorheostosis is an unusual mesenchymal dysplasia, which commonly presents on radiographs as longitudinal bars of hyperostosis in osseous structures. We present a case of melorheostosis in the lower extremity of a 20-year-old woman for which detailed radiologic- pathologic correlation was achieved due to amputation of the involved limb.

Inflammatory foreign-body reaction to an arthroscopic bioabsorbable meniscal arrow repair.

Various arthroscopic meniscal repair techniques have been developed in recent years to preserve meniscal function. We report the case of a patient with a failed arthroscopic meniscal repair demonstrating an inflammatory foreign-body reaction to bioabsorbable meniscal arrows.

Chondrosarcoma of the short tubular bones of the hands and feet.

OBJECTIVE: To report 12 cases of chondrosarcoma in a rare location, the short tubular bones of the hands and feet, as well as 12 cases of enchondroma in similar locations, emphasizing the radiologic and histopathologic features. DESIGN AND PATIENTS: All relevant cases that had both histologic slides and radiographs available were taken from the files of one orthopedic referral hospital and the personal files of one of the authors. A similar number of enchondroma cases was selected at random from the files. RESULTS AND CONCLUSIONS: One malignancy arose in a background of enchondromatosis, with all the others being solitary lesions. A pathologic diagnosis of malignancy is often difficult in the absence of radiologic signs of malignancy (cortical destruction with or without soft tissue extension). However, three cases were unusual in that the initial radiograph demonstrated a benign appearance. Another group of three malignancies was surprisingly indolent biologically. The treatment of choice is ray resection (or more limited amputation in a lesion of the middle or distal phalanx).

Bifocal sclerosing osteosarcoma: unusual presentation and course.

Multifocal osteosarcoma is uncommon. Long-term survival of an incompletely treated case is exceptional. We report an unusual case of bifocal sclerosing osteosarcoma in a 38-year-old women that involved the left ilium and right proximal femur. The femoral lesion was resected. The tumor in the left ilium was not treated. She did not receive chemotherapy and has been free of metastases for 7 years. Recently, growth of the pelvic osteosarcoma has resulted in vascular compression and edema of the lower extremity. The patient's alkaline phosphatase has been elevated throughout. The tumor was HMB-45 positive, which has not been previously reported in osteosarcoma. The pathogenesis of multifocal osteosarcoma is discussed.

Osteofibrous dysplasia-like adamantinoma of bone: a report of five cases with immunohistochemical and ultrastructural studies.

This report describes five cases of osteofibrous dysplasia-like adamantinoma of the tibia in young patients ranging from ages 4 1/2 to 14 years. Radiologically and histologically, these cases were indistinguishable from osteofibrous dysplasia of bone, and no epithelial cells were recognized on routine staining. However, epithelial differentiation was seen in the form of scattered keratin-positive cells in all five cases, and tonofilaments in four cases. The patients were treated by curettage, and three had recurrences. Follow-up showed no progression to classic adamantinoma. Osteofibrous dysplasia-like adamantinoma is a special histological type of adamantinoma that affects children and adolescents. It differs from classic adamantinoma in that it lacks conspicuous nests and masses of epithelial cells, and the prognosis after conservative treatment is generally good. Recent publications suggest that osteofibrous dysplasia-like adamantinoma is a precursor of classic adamantinoma. In a comparative study of three cases of classic adamantinoma, we found, in the fibroblastic stroma of the tumors, spindle epithelial cells that were indistinguishable from the epithelial cells of osteofibrous dysplasia-like adamantinoma. This finding suggests that there is an overlap between these conditions. Four additional cases of osteofibrous dysplasia of the tibia from our files lacked epithelial differentiation. It is most likely that osteofibrous dysplasia is part of the morphologic spectrum of adamantinoma.

Regulation of nitric oxide production by salicylates and tenidap in human OA-affected cartilage, rat chondrosarcomas and bovine chondrocytes.

OBJECTIVE: To examine the effects of non-steroidal anti-inflammatory drugs (NSAIDS) on nitric oxide (NO) and prostaglandin E2 (PGE2) production in chondrocytes from three different species. METHODS: We have estimated NO production by Griess method, and PGE2 by RIA from the supernatants of articular cartilage obtained from osteoarthritis joints (OA-affected cartilage), rat chondrosarcomas (in ex vivo conditions) and bovine chondrocytes (stimulated with cytokines + endotoxin in vitro conditions) in the presence or absence of aspirin, indomethacin, sodium salicylate, tenidap and glucocorticoids. RESULTS: NO, which was spontaneously released in ex vivo conditions by OA-affected cartilage and rat chondrosarcomas (maintained in vivo), was susceptible to inhibition by pharmacologically relevant concentrations of aspirin, sodium salicylate and tenidap, but not to concentrations of indomethacin or glucocorticoids that significantly inhibited PGE2 production under the same conditions. Similarly, the production of NO by bovine chondrocytes grown in monolayer cultures that had been stimulated with cytokines + endotoxins (in vitro) to release both NO and PGE2 (at 48-72 h post stimulation), were inhibited by aspirin, sodium salicylate and tenidap, but not by indomethacin or glucocorticoids at concentrations sufficient to PGE2 production. Inhibition of NO in the cytokines + endotoxin stimulated bovine chondrocytes (like the human OA-affected cartilage) augmented PGE2 production. CONCLUSION: These experiments demonstrate that NO production by chondrocytes across species show a similar profile of susceptibility to inhibition by selected anti-inflammatory drugs. The insensitivity of NO production to glucocorticoids is an important characteristics of these cells that merits further investigation.

Expression of metalloproteinases and tissue inhibitors of metalloproteinases in giant cell tumor of bone: an immunohistochemical study with clinical correlation.

The clinical behavior of giant cell tumors (GCTs) is unpredictable. To gain insight into this tumor's biological behavior, matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) were studied. These substances play essential roles in wound healing and neoplastic invasion and metastasis. Paraffin-embedded tissue was collected from 18 cases of histologically benign GCT, with 17 treated by curettage and 1 by resection. Eight cases showed no recurrence after a minimum of 2.5 years, and 10 had local recurrence. One showed metastasis. Antibodies to MMP-9, MMP-2, TIMP-1, and TIMP-2 were applied by immunohistochemical methods. In all cases, MMP-9 was strongly expressed in giant cells predominantly in a diffuse pattern and was strong but focal in stromal cells. MMP-2 decorated stromal cells and giant cells heterogeneously. TIMP-1 was variably expressed in giant cells of the nonrecurrent cases and was strongly present in a diffuse or patchy distribution in the stromal cells in 6 of 8 cases. However, in 9 of 10 recurrent cases, TIMP-1 was expressed weakly by both giant and stromal cells. TIMP-2 was variably expressed in the giant cells of the nonrecurrent cases, but 6 of 8 nonrecurrent cases showed strong stromal cell positivity for TIMP-2. Weak staining for TIMP-2 was observed in 7 of 10 recurrent cases in the stromal cells and 9 of 10 recurrent cases in the giant cells. These results indicate that expression of MMPs and TIMPs differs in giant cells and stromal cells in the same tumor. More significantly, in contrast to the nonrecurrent giant cell tumors, there is an imbalance in the MMPs and TIMPs in the recurrent tumors with a net excess of MMPs. This unopposed expression of MMPs in GCTs may play a role in breakdown of extracellular matrix and tissue invasion. Finally, these markers may prove useful in predicting behavior in these tumors.

Sarcoma in association with bone infarcts. Report of five cases.

Sarcoma associated with bone infarct is rare, and only 41 well-documented cases have been published. We describe five additional patients, three women and two men, aged 39 to 57 years. The tumors involved the femur (three patients), tibia (one patient), and humerus (one patient). In three patients, the infarcts were idiopathic. Radiologic evidence of malignancy was found in all patients, and bone infarcts were suspected in four. Four of the patients had malignant fibrous histiocytoma and one an osteosarcoma. Histologically, bone infarcts were seen in all patients, but in three they were mostly replaced by tumor. Portions of intact infarcts were seen adjacent to the tumor, indicating that they had preceded the development of the sarcoma. No hypercellular or atypical reparative tissue was found in the infarcted bones or in three additional uncomplicated infarcts studied from the same patients. The pathogenesis of sarcoma arising in bone infarct is unknown. The prognosis is poor; four of our five patients died within 2 years.

Ganciclovir intraocular implant. A clinicopathologic study.

BACKGROUND: Surgical implantation of the intraocular sustained-release ganciclovir device is a safe and effective treatment for cytomegalovirus (CMV) retinitis. Previous histopathologic studies on eyes containing such implants have been limited by the necessity of removing the device before processing. Microtome sectioning of hard plastics within paraffin-embedded blocks is infeasible, and the anatomic relations of implant to eye are destroyed. METHODS: The authors studied four eyes from three patients who had undergone implant insertion. Globes with implants in place were fixed in neutral 10% formation, embedded in methylmethacrylate, sectioned on a special microtome, and stained with hematoxylin-eosin. RESULTS: After methacrylate embedding, the precise anatomic relations of the implant to the neighboring uveoscleral coats were preserved. In two eyes, the suture tab of the implant protruded through the sclera, exiting subconjunctivally. In two eyes, the implant was totally intravitreal. In all patients, the device was supported by fibrous tissue which emanated from a surgical coloboma of the pars plana ciliaris. Focal granulomatous inflammation adjoined suture and implant materials but no other inflammation or deleterious effects on the ocular structures were noted. CONCLUSION: This report is the first to document the intraocular histopathology of the ganciclovir implant. The subconjunctival location, enhancing the potential for endophthalmitis, may be avoided by trimming of the suture tab close to the anchoring suture and not tying it too tightly. Methylmethacrylate embedding is a useful technique for preserving the microanatomy of intraocular implants.

Myxoid chondrosarcoma of soft tissue and bone: a retrospective study of 11 cases.

This article describes 11 cases of myxoid chondrosarcoma (MCS), with 10 arising in soft tissues and one developing in bone. Most of the tumors (six) were located in the lower extremities. Two lesions developed in the fingers, a previously unreported location for MCS. Four cases showed secondary bone destruction, which is a rare feature of this tumor. S100 protein was expressed by tumor cells in all the specimens. Four out of eight tumors studied by electron microscopy contained intracisternal microtubular structures. Two tumors showed areas of spindle cell proliferation that merged with the areas of typical myxoid pattern. The cells in these areas had fibroblastic/myofibroblastic features by electron microscopy and were found to express cytokeratin by immunohistochemistry. The concomitant expression of cytokeratin and S100 protein in the spindle cells suggests that they represent a less differentiated cartilaginous component with unusual features. The clinical significance of the presence of such spindle cell areas presently remains unknown. Although myxoid chondrosarcoma is a slow-growing tumor, it has a high potential for metastases. Four of 11 patients in this series developed metastases.

Osteosarcoma: subtle, rare, and misleading plain film features.

Osteosarcoma is a malignant, mesenchymal, osteoid, and bone-forming tumor [1-3]. In most cases, typical radiographic features clearly illustrate the aggressive bone-forming nature of the lesion. These features include long-bone metaphyseal location, mixed areas of lysis and sclerosis, cortical destruction, periosteal new bone, and soft-tissue mass. However, numerous factors contribute to misleading radiographic patterns of osteosarcoma. They include histologic low-grade, lytic, or minimally sclerotic lesions, early detection, confinement to the intramedullary canal, benign-appearing periosteal reaction, rare intraosseous locations (subchondral, diaphyseal, intracortical), and rare skeletal sites (e.g., soft tissues, skull, ribs, tarsal bones). Secondary osteosarcomas, such as those arising from infarcts or fibrous dysplasia, may also produce a confusing radiologic picture. The purpose of this pictorial essay is to illustrate cases of osteosarcoma that proved to be difficult diagnostic dilemmas because of their subtle, rare, or misleading plain film features.

Ewing's sarcoma of humerus with epithelial differentiation.

We report an unusual case of Ewing's sarcoma of the humerus with epithelial differentiation. This rare finding has recently been documented in this type of tumor.

Intracapsular and paraarticular chondromas.

Intracapsular and paraarticular chondromas are rare benign tumors. The authors report four such lesions, three of which occurred about the knee and one at the hip. Radiographs showed calcified soft-tissue masses in the infrapatellar region of the knee in three patients. In the hip, the lesion was not visible on conventional radiographs. Three lesions originated from the joint capsule and one was extracapsular. These lesions should be differentiated from synovial chondromatosis and other calcified lesions occurring about the joints. After local excision, the tumors usually do not recur.

Cystic angiomatosis of bone with sclerotic changes mimicking osteoblastic metastases.

Five unusual cases of cystic angiomatosis of bone which presented with the radiologic appearance of osteoblastic lesions are reported. Three patients were female (ages 37, 41, and 65 years) and two were male (ages 24 and 66 years). Although cystic angiomatosis of bone usually produces widespread osteolytic lesions with a honeycombed appearance in the skeletal system, multiple osteoblastic lesions mimicking metastatic osteoblastic carcinoma are sometimes seen. This radiological presentation has not been well emphasized in previous reports. Histologically, in addition to the angiomatous lesions, both mature thickened lamellar bone trabeculae and immature trabeculae of woven bone were found. In one of our patients, increasing density of the osteoblastic lesions was noted over time. One previous study has suggested that the age of the lesions of cystic angiomatosis is related to radiographic density. It is important to recognize this uncommon variant of cystic angiomatosis and to include this entity among the radiologic differential diagnoses when multiple osteoblastic lesions are encountered.

Calcified spherules in fibro-osseous lesions of bone.

We present 20 examples of fibro-osseous lesions of bone, characterized by the presence of varying numbers of rounded calcified structures (calcified spherules). In the past, such lesions have been regarded as ossifying fibromas or cementifying fibromas, the latter because of their histologic similarity to jaw lesions known by that name. In the present series, six lesions showed, in addition to the calcified spherules, typical histologic features of fibrous dysplasia, while a further seven showed atypical bony structures that also suggest a link with fibrous dysplasia. This study has led us to conclude that these lesions of the extragnathic skeleton, containing rounded calcified spherules, represent a variant of fibrous dysplasia.

Eosinophilic granuloma: MRI manifestations.

The appearance on magnetic resonance imaging (MRI) of 16 cases of pathologically proven eosinophilic granuloma were reviewed retrospectively and correlated with the radiographic appearance of the lesion. The most common MR appearance (ten cases) was a focal lesion, surrounded by an extensive, ill-defined bone marrow and soft tissue reaction with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, considered to represent bone marrow and soft tissue edema (the flare phenomenon). The MRI manifestations of eosinophilic granuloma, especially during the early stages, are nonspecific, and may stimulate an aggressive lesion such as osteomyelitis or Ewings sarcoma, or other benign bone tumors such as osteoid osteoma or chondroblastoma.

In situ analysis of Paget's disease of bone for measles-specific PCR-amplified cDNA.

Paget's disease of bone is a disease of unknown etiology. The demonstration of viral-like particles on ultrastructural examination and the putative detection of viral antibodies and nucleic acids in the tissues suggest a possible viral association. The purpose of this study was to search for nucleic acid sequences homologous to measles virus using the recently described reverse transcriptase (RT) polymerase chain reaction (PCR) in situ hybridization (ISH) technique. After performing RT PCR ISH utilizing primers specific for the nucleocapsid region of the measles virus, an intense signal was evident in most measles-infected HeLa cells compared with a weak signal in few of these cells using standard cDNA-RNA ISH analysis. Amplified measles nucleic acid was detected in tissue from a patient who died of measles infection and was not detected in any of the 11 cases of Paget's disease of bone studied or in a giant cell tumor of bone that had tubuloreticular inclusions on electron microscopy. Therefore, these data suggest that infection by the measles virus is not associated with Paget's disease of bone.

Pathology of osteonecrosis of the femoral head. A review of experience at the Hospital for Joint Diseases, New York.

Pathological examination of the resected femoral heads from approximately 2000 total hip replacement operations carried out at the Hospital for Joint Diseases from 1984 to 1989 identified the presence of osteonecrosis in 345 patients (377 femoral heads). In 232 patients the osteonecrosis, referred to as "idiopathic," had occurred in the absence of a subcapital fracture. The present paper describes the pathology of the necrotic lesions in these 232 patients. The use of undecalcified sections and microradiography provides evidence of bone marrow calcification which, at the margin of the lesion, is sufficient to influence the radiographic features of the lesion significantly. Although a subchondral fracture is an almost constant feature of osteonecrosis when it occurs in a femoral head with a normal articular cartilage, no such fracture was found in cases in which osteonecrosis had occurred in an osteoarthritic joint.