Accuracy of cytology for diagnosis of lipomatous tumors: comparison with magnetic resonance and computed tomography findings in 175 cases.

PURPOSE: To assess the value of fine-needle aspiration cytology in the diagnostic work-up of lipomatous tumors of the extremities and trunk, and to identify specific radiological features that could aid in the preoperative evaluation. MATERIAL AND METHODS: 175 patients with subfascial lipomatous tumors who had undergone preoperative magnetic resonance imaging or computed tomography and fine-needle aspiration cytology were studied. The percentage of fat within the lesion was visually graded from the images as: none, 1-75%, 75-95%, or 95-100%. The histological and cytological diagnoses were compared and in discordant cases the radiological images were re-reviewed. RESULTS: There was cytological and histological concordance in 96% of lipomas and in 85% of atypical lipomatous tumors (ALT) and liposarcomas. Most discordant cases exhibited 1-75% fat. Radiological review suggested that cytological sampling problems due to tumor heterogeneity were the main cause of diagnostic difficulties. The majority of tumors with less than 75% fat were liposarcomas, and in no liposarcoma was the fat content higher than 75%. Both ALT and lipoma were found in the 95-100% group. CONCLUSION: Cytology can be highly accurate in the diagnosis of lipomatous tumors, including ALT; however, critical comparison with the radiological findings increases diagnostic security. In tumors with fat content visually assessed as less than 75% of the tumor volume, liposarcoma is the most likely diagnosis and a cytological diagnosis of ALT or lipoma should be questioned. In lesions with 75-95% fat, liposarcoma is unlikely, but FNAC is still indicated for safety. In lesions with 95-100% fat, FNAC is only indicated if the differentiation between lipoma and ALT influences the treatment strategy.

Risk factors for nosocomial intensive care infection: a long-term prospective analysis.

BACKGROUND: To identify risk factors for nosocomial infection in intensive care and to provide a basis for allocation of resources. METHODS: Long-term prospective incidence study of risk factors for nosocomial infection in the surgical-medical intensive care unit of a university hospital. RESULTS: A total of 2671 patients were admitted during four years, and 562 of 574 patients staying >48 h were observed during 4921 patient days (median length of stay 5 days, range 2-114). Of these, 196 (34%) patients had 364 nosocomial infections after median 8-10 days, an infection rate of 14/100 admissions. Infection prolonged length of stay 8-9 days and doubled the risk of death. The infections were 17% blood stream, 26% pneumonias, 34% wound, 10% urinary tract and 13% other infections. The incidence of bloodstream infection declined significantly during the study years, from 12% to 5%. In multiple regression analysis, the important variables for infection were central venous catheter, mechanical ventilation, pleural drainage and trauma with open fractures. High age, immunosuppression and infection on admission did not influence the risk of acquiring infection. Trauma patients constituted 24% of the study population. Trauma with open fractures increased the risk of infection more than twice (P=0.003), mainly due to wound infections. CONCLUSION: Trauma cases, with open fractures, were the patients most at risk of infection, despite low disease severity scores. Resources to prevent nosocomial infection should be allocated to these patients.

Diagnosis of skeletal lymphoma and myeloma by radiology and fine needle aspiration cytology.

Diagnosis of skeletal lymphoma and myeloma by radiology and fine needle aspiration cytology From 1986 to 1998, all patients referred to Karolinska Hospital because of a skeletal destruction of unknown origin routinely underwent radiographic examination and fine needle aspiration cytology (FNAC). Among these, there were 83 patients with solitary lesions of the bone diagnosed and treated for myeloma (plasmacytoma) or non-Hodgkin's lymphoma. Review of the series showed that myeloma could not be distinguished radiographically from lymphoma. Nor could low and high grade lymphoma lesions be discriminated by radiographic appearance. The diagnostic utility of plain radiography in the two conditions seems to be confined to the mere detection of a destructive bone lesion and visual guidance for FNAC. The latter aspect, however, is crucial for the application of FNAC to bone lesions. Review of the cytologic specimens obtained by FNAC showed that they allowed a conclusive diagnosis in all 40 myeloma cases and in 41 of 43 lymphoma cases. In 32 of the 40 myeloma cases, the FNAC material could be used for immunocytochemistry, which disclosed kappa or lambda light chain restriction, corroborating the cytomorphological diagnosis. Thirty-eight lymphomas were characterized immunologically and in 35, a light chain restriction could be demonstrated. Our results show that the use of FNAC in the diagnosis of primary myeloma and lymphoma of bone obviates the need for other diagnostic modalities, including open biopsy. A combined approach based on radiology and FNAC, performed as an out-patient procedure, offers rapid and accurate diagnosis of myeloma and lymphoma among patients with radiographically unclassified destructive bone lesions.

Cytological diagnosis of skeletal lesions. Fine-needle aspiration biopsy in 110 tumours.

We have previously shown that cytological diagnosis based on fine-needle aspiration biopsy (FNAB) is a safe and efficient method for the discrimination between benign, primary malignant and metastatic bony lesions. We have now studied metastatic lesions to assess the diagnostic accuracy and to ascertain whether FNAB allows identification of the primary lesion. Between 1990 and 1997, 447 patients were referred for diagnosis of skeletal lesions of unknown type. Of these 119 proved to have metastatic disease, either myeloma or lymphoma. Nine were excluded leaving 110 consecutive patients with metastatic carcinoma (80), myeloma (16) or lymphoma (14). FNAB gave a correct diagnosis in 102 of the 110 patients (93%). In eight it was inconclusive. It correctly diagnosed 15 of 16 patients with myeloma, 12 of 14 with lymphoma, and 75 of 80 with metastatic carcinoma. Furthermore, the site and type of malignancy were correctly suggested in two-thirds of patients with metastatic carcinoma. Overall, only seven open biopsies were carried out. We conclude that time-consuming and costly investigations can be reduced by choosing FNAB as the initial diagnostic method for skeletal lesions of unknown origin. The choice of radiological examinations, laboratory tests and surgical biopsies can be determined by using FNAB.

110 subfascial lipomatous tumors. MR and CT findings versus histopathological diagnosis and cytogenetic analysis.

PURPOSE: To evaluate whether liposarcoma, atypical lipomatous tumors and lipoma can be differentiated radiologically. MATERIAL AND METHODS: We have retrospectively analyzed CT and/or MR images of 110 subfascial lipomatous lesions. The amount of fat within the tumors was visually graded from the images as: none, 1-75%, 75-95% or 95-100%. The structure of non-fatty tumor components was compared. The images were compared to histopathology and in 37 cases to cytogenetic findings. RESULTS: Only 4 of 20 liposarcomas contained fat. All 4 lesions, histopathologically diagnosed as atypical lipomatous tumors, contained fat but less than 75% of tumor volume. All lesions with more fat than 75% of tumor volume were histologically diagnosed as lipomas. However, one-third of the karyotyped lipomas had ring chromosomes which are considered typical for atypical lipomatous tumors. CONCLUSION: When a tumor is composed more or less solely of fat, the diagnosis of a lipoma or atypical lipomatous tumor with a phenotype simulating a lipoma can be assumed. When the fat content is less than 75% of the tumor volume or non-fatty nodules are found, biopsies from different tumor components have to be performed to exclude malignancy. When no fat is found, imaging does not help in differentiating lipoma or liposarcoma from other soft tissue tumors.

MR imaging of lipoma and liposarcoma.

PURPOSE: To evaluate whether lipoma, atypical lipomatous tumors, and liposarcomas can be differentiated by MR images. MATERIAL AND METHODS: The MR images of 59 lipomatous lesions and liposarcomas were retrospectively reviewed. Apart from size, surgical site, location and margins, the percentage of fat of the tumor volume was assessed as none, 1-75%, 75-95%, or 95-100%. RESULTS: None of the 18 liposarcomas contained fat that could be recognized by MR imaging. The 3 atypical lipomatous tumors all contained fat but less than 75% of the tumor volume. In 32 of 38 ordinary lipomas, the percentage of fat was 95-100%, and in 4 less than 95% of the tumor volume. Two lipomas did not contain fat that could be recognized by MR imaging. CONCLUSION: A lesion which predominantly has a fat signal is, in all probability, an ordinary lipoma. Lesions with less fat, but still mostly fatty, may either be lipoma or atypical lipomatous tumor. In this group, the discrimination between these two entities cannot be based upon imaging features. In the absence of a fat signal, liposarcoma or lipoma cannot be differentiated from other soft tissue tumors.

Fine needle aspiration (FNA) cytology in the diagnosis of recurrent soft tissue sarcoma.

We have used FNA cytology to diagnose suspected local recurrences of soft tissue sarcoma. Since 1991, a total of 95 FNA cytologies were performed on 86 patients. There were 47 local recurrences, of which 44 were diagnosed correctly by FNA cytology; one biopsy was inconclusive, and two lesions were incorrectly assessed as benign. Thirty-nine patients proved to have benign lesions in the scar area examined cytologically on 50 occasions. None of the specimens was regarded as malignant, but in four cases FNA cytology was inconclusive. Overall, there were 5% inconclusive cytological biopsies, 0% falsely malignant and 5% falsely benign. The inconclusive and false-negative cytological diagnoses had no important clinical consequences. FNA biopsy provides a simple means of diagnosing local recurrence of soft tissue sarcoma.

Comparison of technetium-99m-MIBI and technetium-99m-tetrofosmin uptake by musculoskeletal sarcomas.

UNLABELLED: Technetium-99m-MIBI was initially developed for heart studies but it can also be used to depict tumors, predict multidrug resistance and evaluate chemotherapy. Recently, 99mTc-tetrofosmin, which exhibits similar physical properties, has been launched for heart studies. Tumor uptake and prediction of multidrug resistance have also been reported regarding the latter tracer. A comparison of these two tracers regarding the detectability of musculoskeletal sarcoma has been made. METHODS: Twenty patients with musculoskeletal sarcoma of the extremities or pelvis underwent planar examination after the administration of 99mTc-MIBI and 99mTc-tetrofosmin with an interval of 2-7 days. The tumor activity was compared with one ipsilateral and one contralateral background region. RESULTS: There was a small, but not significant, difference in favor of 99mTc-MIBI with regard to both background regions. CONCLUSION: Technetium-99m-MIBI and 99mTc-tetrofosmin can both be used to visualize musculoskeletal sarcomas. The choice may depend on which agent is used routinely for myocardial studies in the laboratory.

Use of 99mTc-MIBI scintigraphy in the evaluation of the response of osteosarcoma to chemotherapy.

The use of gamma camera scintigraphy with technetium-99m hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) for assessment of the response of high-grade osteosarcoma to preoperative chemotherapy was evaluated. Twelve patients with osteosarcoma of the extremities underwent planar examination with 99mTc-MIBI before and after preoperative chemotherapy according to the recommendations of the Scandinavian Sarcoma Group. After calculating a quotient for the tumour and the average activity of both extremities and correcting for background activity, the change in uptake between the two examinations was assessed. This was compared with histological examination of the ultimately resected specimen in 11 patients and progressive clinical disease in one. All the 11 tumours undergoing histological examination showed cellular necrosis of between 50% and 100% as well as a reduced uptake of 99mTc-MIBI, while the single progressive tumour showed an increased uptake. There was a correlation between the reduction of radiopharmaceutical uptake and the histological response in the entire series, while the variation was too large to allow conclusions in individual patients. This variation may have biological reasons or may be due to the planar imaging technique, which only allows semiquantitative evaluation. The technique reflects response to therapy but is not yet clinically applicable for the identification of poor responders, which would serve as a basis for alteration of the chemotherapy regimen. In order to evaluate whether such a role could be fulfilled, further studies using single-photon emission tomography with correction for attenuation and scattering of photons are necessary.

Magnetic resonance imaging of lower extremity muscles and isokinetic strength in foot dorsiflexors in patients with prior polio.

The thigh and lower leg of six patients with prior polio were examined using magnetic resonance imaging (MRI), and the strength of their weak foot dorsiflexors was measured isokinetically. Spinecho images of the lower extremities were visually evaluated on a semi-quantitative four-point scale, and T1 and T2 relaxation times of the lower leg anterior compartment were analysed. There were prominent MRI signs of randomly distributed muscle degeneration. The high signal intensity changes in the affected muscles on T1-weighted images and T1 and T2 values indicated replacement of muscle fibres with fat and the accumulation of tissue water, respectively. MRI findings were compared with isokinetic strength in foot dorsiflexor muscles. Foot dorsiflexor peak torque values at 30 deg/s ranged from 6 to 29 Nm. There was no significant correlation between MRI visual scoring, T1 and T2 relaxation times and peak torque values at 30 deg/s. However, the most severe MRI changes with visual scoring and T2 relaxation times were observed in the patients with the most pronounced muscle weakness.

MR imaging of skeletal muscle hemangiomas. A report of 16 cases.

PURPOSE: Our purpose was to evaluate how MR imaging depicts the vascular fibrofatty structure of hemangiomas. MATERIAL AND METHODS: MR images of 16 histologically proven skeletal muscle hemangiomas were reviewed retrospectively in a nonblinded manner. One patient was examined at 0.5 T, 9 at 1.0 T, and 6 at 1.5 T, and the imaging protocols varied. RESULTS: All lesions were lobulated/tubular. Signal characteristics of fat were seen in 13 lesions as lace-like thin septa within or around the tumor. All 16 studies exhibited a hyperintense signal on T2-weighted spin-echo (SE) (n=15) or T1-weighted fast fat suppressed inversion recovery SE images (n=1). Postcontrast images showed marked signal enhancement in parts of the areas, both of high and low T2-weighted signal. Surgical staging based on MR images was correct in all lesions. CONCLUSION: MR images display the characteristic vascular fibrofatty structure of hemangiomas and may allow correct diagnosis.

Cytological diagnosis of bone tumours.

We evaluated the diagnostic accuracy of fine-needle aspiration biopsy in a prospective study of 300 patients with previously undiagnosed bone lesions. Patients with suspected local recurrence of a primary bone tumour or a metastatic lesion of a previously diagnosed malignancy were excluded. Fine-needle aspiration biopsy was performed under radiological control as an outpatient procedure. The series was grouped into three major categories: 1) benign bone lesions including infections; 2) primary malignant bone tumours; and 3) metastases including lymphomas and myelomas. We compared the cytological diagnosis with the final diagnosis as assessed by histological examination and/or the clinical and radiological features. Material considered conclusive for cytological diagnosis was obtained from 251 of the 300 patients. Of the 49 failures, there were 24 aspirates with insufficient cellular yield and 25 in which a diagnosis could not be made although the cytological material was adequate in quantity. Most of the inconclusive aspirates (36/49) were obtained from benign bone lesions. The diagnosis was correct in 239 (95%) of the 251 cases providing adequate cytological material. There were eight (3%) falsely benign diagnoses, one (0.3%) falsely malignant, and three cases in which we were unable to differentiate between sarcoma and a metastasis. Chondrosarcoma (2/12) gave the greatest diagnostic difficulty and Ewing's sarcoma the least (0/9). There were no decisive errors of treatment. All falsely benign or malignant diagnoses were questioned, and led to open biopsy since they did not correlate with the clinical and radiological features. Our study suggests that fine-needle aspiration biopsy is a valid option for the diagnosis of bone tumours. It is a simple outpatient procedure which gives sufficient cytological material for the correct diagnosis in 80% of cases. As with histological analysis of material from open biopsy, the cytological assessment must agree with the clinical and radiological findings.

Radiological diagnosis of skeletal metastases.

The clinical management of patients with skeletal metastases puts new demands on imaging. The radiological imaging in screening for skeletal metastases entails detection, metastatic site description and radiologically guided biopsy for morphological typing and diagnosis. Regarding sensitivity and the ease in performing surveys of the whole skeleton, radionuclide bone scintigraphy still is the first choice in routine follow-up of asymptomatic patients with metastatic disease of the skeleton. A negative scan has to be re-evaluated with other findings, with emphasis on the possibility of a false-negative result. Screening for metastases in patients with local symptoms or pain is best accomplished by a combination of radiography and MRI. Water-weighted sequences are superior in sensitivity and in detection of metastases. Standard spin-echo sequences on the other hand are superior in metastatic site description and in detection of intraspinal metastases. MRI is helpful in differentiating between malignant disease, infection, benign vertebral collapse, insufficiency fracture after radiation therapy, degenerative vertebral disease and benign skeletal lesions. About 30% of patients with known cancer have benign causes of radiographic abnormalities. Most of these are related to degenerative diseases and are often easily diagnosed. However, due to overlap in MRI characteristics, bone biopsy sometimes is essential for differentiating between malignant and nonmalignant lesions. Performing bone biopsy and aspiration cytology by radiologist and cytologist in co-operation has proven highly accurate in diagnosing bone lesions. The procedure involves low risk to the patient and provides a morphological diagnosis. Once a suspected metastatic lesion is detected, irrespective of modality, the morphological diagnosis determines the appropriate work-up imaging with respect to the therapy alternatives. The integration of multimodality imaging in the assessment of skeletal metastases is complex and requires multidiciplinary co-operation in order to optimize screening and medical clinical care with respect to the prognosis and life quality of patients with bone metastatic disease.

Boston brace in the treatment of idiopathic scoliosis.

In a retrospective follow-up study of 64 patients with adolescent idiopathic scoliosis, the initial correction of Boston brace with straight lumbar profile strongly predicted good treatment results at follow-up (mean, 4.8 years). If the initial correction was > 50%, the curve was permanently reduced with an average of 7.2 degrees. The average initial correction was 62%. This initial brace effect was preserved in another comparable group of 60 patients treated with a Boston brace with 15 degrees lumbar lordosis. It is concluded that the Boston brace is effective in the conservative treatment of idiopathic scoliosis, and the corrective ability seemingly does not deteriorate with a change in the brace design from 0 to 15 degrees lordosis.

Long-term adjuvant interferon treatment of human osteosarcoma. A pilot study.

During the period from 1971 to 1990 all osteosarcoma patients referred to the Karolinska Hospital without signs of metastases received human leukocyte interferon (IFN) as adjuvant treatment. Patients referred between 1985 and 1990 were given more intensive human leukocyte IFN treatment, i.e. a standard dose of 3 MU s.c. daily for 3-5 years. These 19 patients, all followed for 5 years, were included in a pilot study which entailed patients with central localization where radical surgery was not feasible. Metastases developed in 9 patients, of whom 3 had local recurrences. Sixty-three percent are free of disease at 5 years. Side-effects were negligible and long-term toxicity practically non-existent. It is suggested that a randomized multicenter IFN trial should be instituted on patients with poor prognosis receiving chemotherapy and/or that IFN treatment should be combined with other therapeutic modalities--irradiation, chemotherapy or anti-angiogenic substances--in osteosarcoma.

MR imaging of benign peripheral nerve sheath tumors.

In a retrospective, nonblind review of MR imaging of 15 benign peripheral nerve neoplasms in 13 patients, the signal pattern of the tumors (including contrast-enhanced images) and stage were assessed. One lesion was subcutaneous, 9 intramuscular, 2 intermuscular and 3 extracompartmental. One lesion was located to the trunk, 5 to the upper extremity and 9 to the lower. The signal on T1-weighted spin-echo images was homogeneous isointense compared to adjacent muscle in 11 lesions and in 2 slightly hyper- and in 2 slightly hypointense. T2-weighted spin-echo images, acquired in all but one examination, showed a hyperintense signal, homogeneous in 8 and centrally inhomogeneous in 6 lesions. Postcontrast T1-weighted images of 11 lesions showed a strong signal, with an inhomogeneous enhancement in the center of the lesion similar to that obtained in T2-weighted images. In 2 cases there were signal characteristics indicating bleeding in the tumor. In one lesion both the nonenhanced and contrast-enhanced T1-weighted images showed a hypointense signal in the tumor center suggestive of intramuscular myxoma. All lesions were well delineated without reactive edema. In all cases, anatomic tumor location was correctly assessed. Although the findings were not pathognomonic for neurinoma, MR imaging provided valuable information confirming the clinical and cytologic assessments.

Assessment of rotation in proximal humeral osteotomy.

The correlation between the shift measured on bone surface in rotatory osteotomy and the radiologic change of the retroversion angle was analyzed. The humeral head retroversion was measured radiographically in 7 isolated humeri by means of a semiaxial projection. All bones were then osteotomized and the humeral head rotated in order to increase and decrease the retroversion. The retroversion was measured radiographically for each new rotational position of the head. The relationship between the measured shift in rotatory osteotomy and the change of retroversion was found to be linear. Twelve patients with recurrent anterior shoulder joint dislocations and a small humeral head retroversion were operated on in order to increase the retroversion. In all patients the increase of retroversion angle was smaller (57%) than expected on the basis of the shift in osteotomy and humeral diameter. The mean increase of retroversion was 2 degrees/mm shift (range 1.3-3.0 degrees/mm).