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R A McLeod

Publications and source records attributed to R A McLeod.

At least 19 recordsLinked to original sources
PubMed1992

Aneurysmal bone cyst. A clinicopathologic study of 238 cases.

Aneurysmal bone cyst (ABC) is a nonneoplastic expansile bone lesion that mainly affects children and young adults. Primary ABC is relatively rare, with an incidence one half that of giant cell tumor of bone. In 238 patients with ABC studied in the Mayo Clinic files, more than 80% of the lesions were in long bones, flat bones, or the spinal column. Of the lesions initially treated at the Mayo Clinic, 95% were typical ABC; the rest were "solid" variants. Except for the absence of obvious cavernous channels and spaces, there was no significant histologic difference between solid variant and typical ABC. Radiographically, ABC is an eccentric expansile lesion commonly located at the metaphysis of long bones. Computed tomography and magnetic resonance imaging may show multiple internal septations or fluid levels. In the 153 patients treated, 19% had recurrence after curettage (intralesional excision). Recurrence was most common during the first 2 postoperative years.

Adolescent↗
PubMed1991

MR imaging of synovial sarcoma.

The MR imaging findings in 12 cases of synovial sarcoma are illustrated. The MR appearance most indicative of the tumor is an inhomogeneous septated mass with infiltrative margins located close to a joint, a tendon, or bursae, especially if soft-tissue calcification can be seen on CT scans or plain radiographs.

Adolescent↗
PubMed1991

Sacral insufficiency fractures: an often unsuspected cause of low back pain.

We describe a patient with sacral insufficiency fractures presenting as acute onset low back pain without antecedent trauma. Sacral insufficiency fractures are an often unsuspected cause of low back pain. The clinical presentation and plain radiograph findings can mimic metastatic disease, leading to unnecessary investigations and treatment. However, the location, linearity, and appearance of these fractures on computed tomography is very characteristic and obviates the need for further evaluation.

Aged↗
PubMed1991

Telangiectatic osteosarcoma.

Telangiectatic osteosarcoma is a rare variant of osteosarcoma. In the original report from the authors' institution, a poor prognosis was noted. The authors have updated their experience with this entity. The prognosis for patients with telangiectatic osteosarcoma has improved remarkably. The prognosis in the present series seems to be the same as that for conventional osteosarcoma. Adjuvant chemotherapy seems to help in salvaging patients with metastatic disease. However, in this small series, survival of patients without metastasis is apparently not influenced by whether they received chemotherapy.

Adolescent↗
PubMed1990

Chondrosarcoma of bone in children.

Chondrosarcoma of bone rarely occurs in children. This report analyzes the clinicopathologic features in a series of 47 patients with conventional chondrosarcoma who were less than 17 years of age. Of the 47 cases, 14 were from the Mayo Clinic files, and 33 were from our consultation files. Most of the lesions occurred in the trunk and upper ends of the long bones, with the humerus being the most frequent skeletal site. Twelve of the 47 tumors were secondary. The radiographic findings were the same as those seen in adult chondrosarcoma. Pathologically, the tumors were low grade. En bloc resection is the treatment of choice because of the high incidence of local recurrence with lesser surgical margins. Prognosis in childhood chondrosarcoma is no different from that in adult chondrosarcoma. None of the patients with follow-up data had metastasis.

Adolescent↗
PubMed1990

Low-grade intraosseous osteosarcoma.

A study of 80 well-differentiated osteosarcomas, 16 from the Mayo Clinic files and 64 from our consultation files, revealed that males and females were about equally affected, most of the patients were young adults, and skeletal distribution was similar to the distribution seen in conventional osteosarcoma. Radiographs generally showed poor margination, suggestive of malignancy. Histologically, the tumors were composed of spindle cells with only minimal atypia. Some tumors had bone spicules similar to those seen in fibrous dysplasia. An invasive growth pattern was the most helpful feature in differentiating low-grade osteosarcoma from fibrous dysplasia. Initial treatment was highly variable. Local excision was almost always associated with recurrence. Wide excision was almost never followed by recurrence. The recurrent tumor was a high-grade, conventional osteosarcoma in 15% of the patients, and this was associated with a poor prognosis. Wide excision seems to be the treatment of choice for this very rare variant of osteosarcoma.

Adolescent↗
PubMed1990

Case report 628: Low-grade central osteosarcoma.

In summary, low-grade central osteosarcoma is a clinically recognizable rare subtype of osteosarcoma, representing 1.9% of all osteosarcomas found at the Mayo Clinic. The lesion is locally aggressive but also has the potential for metastasis, particularly after local recurrence. The tumor may be difficult to distinguish radiographically and histologically from benign conditions, particularly fibrous dysplasia. This difficulty has led to inadequate treatment. In most cases, a wide surgical margin achieved by either local resection or amputation should result in a cure. Because of the low metastatic potential of the initial lesion, there seems to be no need for adjuvant chemotherapy.

Adult↗
PubMed1990

Masses of the hand and wrist: detection and characterization with MR imaging.

To assess the value of MR imaging in the detection, delineation, and characterization of mass lesions of the hand and wrist, we reviewed the MR imaging findings of 38 patients referred for evaluation of such lesions. Twenty-five patients had a palpable mass. In an additional 13 patients an occult mass lesion was suspected as the cause of distal ulnar neuropathy. Twenty-two mass lesions (16 benign and six malignant) were detected by MR. All were correctly predicted to be benign or malignant. In nine (56%) of the 16 benign mass lesions, the specific diagnosis was suggested. In the remaining seven benign mass lesions and in the six malignant tumors, the MR findings were not specific enough to permit a diagnosis. Of the 14 patients referred for evaluation of a distal ulnar neuropathy, an occult ganglionic cyst compressing the ulnar nerve was revealed with MR imaging in three. MR imaging of the hand and wrist is accurate in the detection of mass lesions and can correctly distinguish benign from malignant tumors in the majority of cases. Specific diagnoses can be made in certain benign lesions. Occult mass lesions can be confirmed or excluded as the cause of distal ulnar neuropathy with MR imaging.

Adolescent↗
PubMed1990

MR imaging of tumor and tumorlike lesions of bone and soft tissue.

This review examines the role of MR imaging in the diagnosis and staging of tumors and tumorlike lesions of bone and soft tissue. For tumors of bone, the plain radiograph is not only the least expensive diagnostic test but is the most reliable predictor of the histologic nature of a given lesion. Consequently, it should be the first procedure performed and serve as the basis for determining the next step in the patient's evaluation. MR imaging is the examination of choice for staging bone tumors. CT is preferred to MR imaging only when the characteristics of the lesion are inadequately defined on plain radiographs, as may occur in flat bones. Although MR imaging is of limited value in predicting the histology of bone tumors, it is a useful tool for distinguishing round-cell tumors and metastases from stress fractures and medullary infarcts in symptomatic patients with normal radiographs. For depiction of soft-tissue masses, MR imaging is unrivaled. The histologic nature of a soft-tissue mass may, in some instances, be predicted on the basis of its MR appearance and multicentricity. Biopsy of bone and soft-tissue tumors should follow and not precede MR imaging. MR imaging reliably shows change in tumor volume after radiation or chemotherapy. It is less reliable in predicting the amount of tumor necrosis.

Bone Neoplasms↗
PubMed1989

Chondroblastoma of bone.

Chondroblastomas are unusual benign lesions of bone. They classically occur at the ends of long bones in young persons. The roentgenographic and histologic features are typical. We had an opportunity to study a large number of chondroblastomas. Most of the cases came from the consultation file started by Dr D. C. Dahlin at the Mayo Clinic. This method of ascertainment may tend to load our series with unusual and atypical examples. We found some unusual locations, such as the skull and facial bones and the small tubular bones of the hands and feet. We also found some unusual histologic features, such as mitotic activity, necrosis, and cellular atypia. However, despite the unusual features, the biological behavior of these tumors was that of a benign process with only limited local aggressiveness.

Adolescent↗
PubMed1989

Chondrosarcoma of the spine.

Twenty patients were diagnosed as having chondrosarcoma of bone that originated in the spine and, except for one, were treated surgically at the Mayo Clinic. The patients' ages ranged from eighteen to seventy years. Pain in the area of involvement was the first symptom in nearly all patients. Nearly one-half of the patients had detected a mass before being diagnosed. In addition, nine patients had neurological symptoms and signs when they were first seen. All patients had a surgical biopsy of the lesion, often combined with decompressive laminectomy. Five patients received postoperative radiation therapy in various dosages. No patient received adjunctive chemotherapy. All but five patients died of local progression of the disease. The five-year survival rate was 55 per cent. The median length of survival was six years. Although it is rare, chondrosarcoma of the spine can usually be identified on radiographs. Preoperative assessment must include computed tomography, magnetic resonance imaging, and, possibly, arteriography to assess the precise extent of the disease. Although surgical ablation often is technically difficult, a wide excision should be attempted. If this is not obtainable, postoperative radiation therapy should be considered.

Adolescent↗
PubMed1988

Xanthoma of bone.

The authors report on 21 cases of "primary" xanthoma of bone. Twenty of the patients were older than 20 years old. The male-female ratio was 2:1. The presenting symptom was pain in 13 patients and neurologic symptoms in 2; in 6 patients, the lesion was an incidental finding. All but one of the lesions in this series were solitary, and the flat bones (pelvis, rib, skull) were the most frequently involved sites. Radiographically, a well-defined, sometimes expansile lytic lesion, with either a small area of surrounding reactive bone or a distinct sclerotic margin, was seen. Microscopically, foam cells, giant cells, cholesterol clefts, and fibrosis were present in varying degrees. In none of these cases was there an identifiable underlying lesion. The differential diagnosis includes Erdheim-Chester disease (a multisystemic granulomatosis) and bone involvement in sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease). More important is the differential diagnosis with metastatic clear cell carcinoma. Xanthoma of bone is a benign lesion, and complete or even partial removal is effective. Xanthomas may represent a "burnt-out" benign condition such as fibrous dysplasia or histiocytosis X.

Adolescent↗
PubMed1988

Primary leiomyosarcoma of bone.

Adequate treatment of primary leiomyosarcoma of bone requires surgical ablation with the goals being those for any malignant tumor of bone--eradication of the lesion and preservation of as much function as possible. Careful preoperative staging will determine whether amputation is necessary or whether successful limb-saving resection is possible.

Aged↗