Veli Söderlund

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 Ewings 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.

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 Lipoma and Liposarcoma

Purpose: To evaluate whether lipoma, atypical lipomatous tumors, and lipo-sarcomas 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.

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.

Cytological diagnosis of skeletal lesions

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.

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.

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

trovik c. s., bauer h. c. f., brosjö o., skoog l. and söderlund v. (1998) Cytopathology9, 320–328

Use of99mTc-MIBI scintigraphy in the evaluation of the response of osteosarcoma to chemotherapy

The use of gamma camera scintigraphy with technetium-99m hexakis-2-methcxyisobutylisonitrile (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 with99mTc-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 of99mTc-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 semi quantitative 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.

Radiologic assessment of humeral head retroversion: description of a new method

A radiologic method for assessment of the humeral head retroversion angle has been developed using one radiograph obtained in the semi-axial view. Validity and reliability of the method has been tested. In five healthy volunteers both shoulders were examined both with CT and with the new radiographic method. The average difference in angle determinations between the methods was 1.5° and the maximum difference was 2°. Angle determination on radiographs from 22 healthy shoulders was performed by two independent radiologists. The coefficient of variation for intraobserver measurements was 2.8 per cent and for interobserver measurements it was 4.6 per cent. Three isolated humerus bones were examined in multiple semi-axial projections and the humeral head retroversion was measured. The effect of humeral position (flexion, extension, abduction) on angle assessments was analyzed. A method error exceeding 2° was only seen when the specimens were in an extended or extremely abducted position. It is concluded that with the arm in the correct position measurements of humeral head retroversion can be performed with this method with high accuracy.

Combined radiology and cytology in the diagnosis of bone lesions: A retrospective study of 370 cases

Background Some of the risks with open biopsy can be avoided by fine-needle aspiration biopsy. The diagnostic contribution of radiologic findings has not been systematically studied. Patients and methods We retrospectively analyzed the validity of combined radiology and fine-needle aspiration cytology for the diagnosis of bone lesions in a consecutive series of 370 patients. The treatment diagnosis was based solely on radiology and cytology in 234 cases, whereas in 136 cases histopathology was also applied. Results Comparison of radiology and cytology showed diagnostic compliance in 256 cases (69%) and non-compliance in 101 (28%). 13 (3%) cases failed to yield diagnostic material for cytology. Among the 256 compliant cases, the diagnostic error rate was 1% (2 were falsely benign), whereas the corresponding rate was 17% among the 101 non-compliant cases. In the latter group, 36 cases yielded only normal cells at aspiration, out of which 20 proved to have a neoplastic lesion (8 metastases, 12 benign). The overall sensitivity of cytology alone in recognizing malignancy was 90%. The specificity was 95%. Given a malignant or benign diagnosis, the positive predictive value was 97% and the negative predictive value was 84%. Interpretation Our study suggests that a simple approach based on conventional radiography and fine-needle aspiration cytology offers a valid means of diagnosing bone lesions. Provided there is compliance between radiology and cytology, the risk of false diagnosis is around 1%.