[The activating GNAS mutation : A survey of fibrous dysplasia, its associated syndromes, and other skeletal and extraskeletal lesions]

Fibrous dysplasia of bone is a connatal but not hereditary disease with monostotic or polyostotic manifestations and may be associated either with the extraskeletal disease McCune-Albright syndrome or with myxoma of the skeletal muscle, termed Mazabraud syndrome.The confirmation of recurrent chromosomal aberrations may lead to the conclusion that fibrous dysplasia is a neoplasia rather than a dysplastic skeletal disease.The primary cause of all forms of the described diseases is the activating GNAS mutation, which is detectable in almost all lesions. Research into the impact of this mutation has increased the understanding of these up to now solely descriptively defined diseases and also allowed easier discrimination of various fibro-osseous skeletal lesions. Current insights suggest that this mutation may also play a pivotal role in other extraskeletal neoplasias.

Radiation exposure to the personnel in the operating room and in the pathology due to SLN detection with Tc-99m-nanocolloid in breast cancer patients

Aim of this study was to assess the radiation exposure for the personnel in the operating room and in the pathology laboratories caused by radioguided SLN localization in breast cancer. Methods: In 15 patients dose rates were measured at various distances from the breast and tumor specimens during operation and pathological work-up at 3-5 h after peritumoral injection of 30 MBq Tc-99m-nanocolloid. Results: The dose rates were 84.1 ± 46.4 μGy/h at 2.5 cm, 3.57 ± 2.14 μGy/h at 30 cm, 0.87 ± 0.51 μGy/h at 100 cm, and 0.40 ± 0.20 μGy/h at 150 cm in the operating room and 44.4 ± 27.8 μGy/h at 2.5 cm, and 1.66 ± 1.34 μGy/h at 30 cm in the pathology laboratories. From these data the radiation exposure was calculated for 250 operations per year assuming a mean exposure time of 30 min for the surgical team members and of 10 min for the pathology staff. Under these conditions the finger dose is 10.5 mGy for the surgeon, and 5.55 mGy for the pathologist. The wholebody doses are 0.45 mSv, 0.11 mSv, 0.05 mSv, and 0.21 mSv for the surgeon, the operating room nurse, the anesthetist, and the pathologist, respectively. Conclusion: Since the radiation risk to staff members is low, a classification of the personnel in the operating room and in the pathology laboratories as occupational radiation exposed workers is not necessary.

Lymph Scintigraphy and Pre- and Intraoperative Gamma Prone Measurements for Localization of Sentinel Lymph Nodes (SLN) in Breast Cancer

Aim of this study was to prove the clinical value of nuclear medicine procedures to detect the sentinel lymph node (SLN) for SLN biopsy. Methods: In 132 patients with breast cancer we performed lymph scintigraphy of the breast as well as both pre- and intraoperative gamma probe measurements correlating the results with the findings of histopathology. Results: SLN were detectable in 62 of 110 patients according to a sensitivity of 56% when scanning was performed only at 1-2 h p.i. while the sensitivity increased to 86% (19 of 22 pts.) if sequential images were acquired up to 2 h p.i. One or more SLN were identified by a handheld gamma probe transcutaneously prior to surgery in 96% (113 of 118 pts.) of the patients who showed up with no clinically suspected lymph node metastases. Intraoperatively, in additionally 2 patients the SLN could be found resulting in a sensitivity of 97% (115 of 118 pts.). In only 3 patients with clinically no tumor spread to axillary lymph nodes no SLN could be identified by the probe. Skip lesions, i.e. lymph node metastases in patients with tumorfree SLN, occured in 2 cases: due to SLN biopsy in these patients lymph node staging was false negative compared to conventional staging by means of axillary lymph node dissection. Conclusion: The results demonstrate a high preoperative detection rate of SLN in patients with breast cancer using lymph scintigraphy and gamma probe measurements. Thus, nuclear medicine is capable of providing the basic requirements for SLN biopsy in the daily routine.

Sentinel node biopsy in breast cancer

The international consensus conference from St. Gallen concerning the treatment of early breast cancer concluded in 2003, that sentinel node biopsy was now accepted as method allowing axillary staging in breast cancer. This procedure may avoid complete lymph node dissection in appropriate cases. Since numerous questions associated with the technique are still not defined and the procedure itself is not yet standardized, the German Society of Senology defined the conditions for the routine clinical use of sentinel node biopsy in an interdisciplinary consensus meeting.

Prä- und intraoperative Volumenbestimmung bei Craniopharyngiomcysten

Die richtige Dosierung des 90Y für die intracavitäre Therapie bei monocystischen Craniopharyngiomen setzt die genaue Bestimmung des Cystenvolumens voraus. Der intraoperativen Volumenbestimmung mittels Radionuklid-Verdünnungsanalyse wurde die präoperative Volumetrie mit Hilfe von Computertomographieaufnahmen gegenübergestellt. Die Ergebnisse beider Verfahren zeigten eine gute übereinstimmung. Zur frühzeitigen Erkennung von Komplikationen werden Aufnahmen mit der Gammakamera als notwendig erachtet.

[Ewing's sarcoma, fibrogenic tumors, giant cell tumor, hemangioma of bone : Radiology and pathology]

Radiological imaging only reflects the anatomy and its pathological abnormalities. Therefore, the radiologist should be able to recognize the basic features of the pathological anatomy of bone tumors. This can only be learned working closely with a pathologist who is experienced in this field. On the other hand, the pathologist needs from the radiologist their diagnostic assessment with information on size, location, aggressiveness and the existence of a bone tumor's matrix, of the whole lesion, because he usually only receives a small part for examination in the form of a biopsy. In this article, the features and fundamentals (standards) of radiological-pathological cooperation as the mainstay for a precise diagnosis in bone tumors are outlined. The radiological appearance and the histopathological features behind it are presented for Ewing's sarcoma, fibrogenic tumors, giant cell tumor, and hemangioma of the bone.

Vascular lesions of the internal auditory canal

We report here two cases of vascular tumors arising within the internal auditory canal, both of which presented with cerebellopontine angle symptoms and simulated acoustic neurinomas. The first case was an arteriovenous malformation that caused moderate sensorineural hearing loss, tinnitus, vertigo with lateropulsion, facial weakness, and trigeminal hypoesthesia on the same side. The second case was a venous angioma, to our knowledge the first ever reported in this location, which presented with sudden complete deafness and progressive hemifacial spasm. The latter subsided completely after successful total extirpation of this unique tumor. The literature on these extremely rare lesions is also reviewed.

Protracted disseminated skeletal metastases from angiosarcoma of the spleen

Angiosarcomas are high-grade vascular tumors associated with poor prognosis due to their aggressive nature. Occasional skeletal manifestations present commonly as osteolytic destruction. The 55-years-old patient presented in this case report had a disease-free 4 years interval between splenectomy after primary angiosarcoma of the spleen and an unusual skeletal metastatic pattern mimicking benign angiomatosis. Despite lacking radiographic evidence for a highly aggressive osseous process, the histopathological resemblance of the bone biopsy with the primary tumor manifestation and the fulminant course of disease after onset of disseminated osseous spread confirmed the malignant character of the vascular tumor. The case demonstrates the highly variable radiographic pattern and particular pathobiological behavior of vascular malignancies.

Brain abscess formation within an endodermal cyst of the frontal lobe: case report

A 38-year-old man with a right frontal lobe cyst was treated by endoscopic cystoventriculostomy in 1998. Cyst capsule histology revealed surprisingly an endodermal cyst. The patient was reoperated for cyst expansion by endoscopic re-cystoventriculostomy in 2005. In 2007, the patient suffered from brain abscess formation within the cyst which was punctured. The history was positive for a dental infection. In 2008, a recurrent brain abscess in the cyst occurred. The cyst was completely resected. There was no history of trauma or sinusitis. In all, endodermal cysts may mimic a paraxial arachnoid cyst. It may predispose for recurrent brain abscess formation - especially due to bacteraemia. This report confirms earlier presentations that endodermal cysts should be resected, and endoscopic cyst opening is not sufficient.

Analysis of c-KIT expression and KIT gene mutation in human mucosal melanomas

Recent data suggested an increased frequency of KIT aberrations in mucosal melanomas, whereas c-KIT in most types of cutaneous melanomas does not appear to be of pathogenetic importance. However, studies investigating the status of the KIT gene in larger, well-characterised groups of patients with mucosal melanomas are lacking. We analysed 44 archival specimens of 39 well-characterised patients with mucosal melanomas of different locations. c-KIT protein expression was determined by immunhistochemistry, KIT gene mutations were analysed by PCR amplification and DNA sequencing of exons 9, 11, 13, 17 and 18. c-KIT protein expression could be shown in 40 out of 44 (91%) tumours in at least 10% of tumour cells. DNA sequence analysis of the KIT was successfully performed in 37 patients. In 6 out of 37 patients (16%) KIT mutations were found, five in exon 11 and one in exon 18. The presence of mutations in exon 11 correlated with a significant stronger immunohistochemical expression of c-KIT protein (P=0.015). Among the six patients with mutations, in two patients the primary tumour was located in the head/neck region, in three patients in the genitourinary tract and in one patient in the anal/rectal area. In conclusion, KIT mutations can be found in a subset of patients with mucosal melanomas irrespective of the location of the primary tumour. Our data encourage therapeutic attempts with tyrosine kinase inhibitors blocking c-KIT in these patients.

[Intratesticular metastasis of renal cancer]

We report on a 66-year-old man after nephrectomy of the right kidney because of renal cell carcinoma. One year after diagnosis, an osseous metastasis of the right femur occurred and was resected. The following investigations, including positron emission tomography/computed tomography, showed no relapse. Three and a half years after diagnosis, the patient developed a testicular tumor of the right hemiscrotum, which was treated by testicular ablation. The histological investigation showed a testicular metastasis of renal cancer. This case represents one of the unusual forms of metastatic invasion of renal cell cancer.

Osteochondrosis dissecans der Hüfte beim Erwachsenen - Differenzialdiagnostik freier Gelenkkörper - Fallbeschreibung

The causes of hip pain in adults can vary greatly. We present the case of a 44-year-old woman with recurrent hip pain over a period of years. Medical history and clinical examination did not provide any decisive information. The X-rays revealed a loose body in the cavity of the hip joint. The MRI scan made the following differential diagnosis plausible: osteochondrosis dissecans coxae, osteochondroma and chondromatosis. The final diagnosis of osteochondrosis dissecans coxae was confirmed by surgical dislocation of the hip as modified by Ganz and histological examination of the loose body. This case supports the importance of including rare lesions in the differential diagnostic work-up of joint pain. The advantages of the offset operation as modified by Ganz versus arthroscopy of the hip are outlined.

Surgical removal of primary central nervous system lymphomas (PCNSL) presenting as space occupying lesions: a series of 33 cases

AIMS

In this study we present a series of 33 patients with primary CNS lymphomas (PCNSL), many presenting with acute signs of increased intracranial pressure due to large space occupying lesions.

METHODS

A series of 32 PCNSL patients for a total of 33 tumours treated from 1986 to 2000 in the Neurosurgical Department were reviewed.

RESULTS

Radiotherapy and chemotherapy improved survival. No benefit could be demonstrated for the role of surgery.

CONCLUSIONS

Our data confirm previous reports about the role of radiation and chemotherapy in the treatment of PCNSL's. Surgery might have a role in a selected subset of patients presenting with large single space occupying lesions and deteriorating neurological status.

[A rare case of isolated prostate metastasis from primary pancreatic cancer]

An otherwise healthy 66 year old male presented with a suspicious intraprostatic lesion detected by digito-rectal examination. Serum PSA levels were normal. A CT scan of the abdomen revealed a nondistinctive mass within the pancreatic head. A transrectal biopsy confirmed the intraprostatic lesion as a metastatic lesion from pancreatic cancer. Therefore, we report this unusual case of a primary pancreatic carcinoma, clinical stage IV, which led to metastases in the liver and prostate.

The prognostic value of progesterone receptor status in meningiomas

BACKGROUND

Meningiomas are known to recur frequently, and their longterm management remains controversial. Previous studies indicate that progesterone and its receptors can play a role in the recurrence of meningiomas, but the correlation between the presence of these receptors and patients' outcome is unclear.

AIM

To conduct a retrospective analysis to investigate the prognostic relevance of progesterone receptor (PR) expression in meningiomas.

METHODS

Five hundred and eighty eight meningiomas operated on over a period of 10 years were examined immunohistochemically to determine the PR status using monoclonal antibodies. Several factors including recurrence (mean follow up of 65 month), sex, tumour tissue consistency, location, vascularity, and en plaque appearance were analysed.

RESULTS

PR status showed comparable values for men and women. World Health Organisation (WHO) grade II and III tumours had significantly fewer receptors than benign meningiomas. There was no significant correlation between PR status and recurrence rates in WHO grade I totally removed meningiomas. However, a combination of PR status and proliferation indices was shown to predict recurrence reliably.

CONCLUSIONS

Together with routine histological evaluation, PR status can help to describe the biological behaviour of meningiomas. Only a combination of clinical and biological features can describe the behaviour of meningiomas, predict their recurrence, and help to devise more effective follow up strategies.

Chondroid tumors arising from the meninges--report of 2 cases and review of the literature

Chondroid tumors are rare intracranial tumors usually arising from the base of the skull. We present 2 cases of intracranial cartilaginous tumors with unusual location. In case 1, a 19-year-old woman, a chondroma of the falx cerebri with extensive secondary ossification was diagnosed. In case 2, a 30-year-old woman, a low-grade chondrosarcoma was resected from the right frontal lobe. Both patients showed an uneventful clinical course without evidence of disease 4.5 and 6 years after total extirpation. Our cases show that chondromas and low-grade chondrosarcomas of the dura and meninges usually occur in young adults with a good prognosis after complete extirpation.

[Sentinel node biopsy in breast cancer]

The international consensus conference from St. Gallen concerning the treatment of early breast cancer concluded in 2003, that sentinel node biopsy was now accepted as method allowing axillary staging in breast cancer. This procedure may avoid complete lymph node dissection in appropriate cases. Since numerous questions associated with the technique are still not defined and the procedure itself is not yet standardized, the German Society of Senology defined the conditions for the routine clinical use of sentinel node biopsy in an interdisciplinary consensus meeting.

The Ki-67 proliferation antigen in meningiomas. Experience in 600 cases

BACKGROUND

Meningiomas are mostly benign tumours that can be cured by surgical resection. Because meningiomas tend to recur, long term management in patients with subtotal tumour resection remains controversial. Previous studies have shown that the proliferation potential of meningiomas by Ki-67 labelling indices (LI) might predict their natural history. The purpose of this study was to analyse the reliability of Ki-67-labelling index in predicting the behaviour of meningiomas, and to help the neurosurgeon in establishing better follow up criteria and long term management strategies for these patients.

METHOD

From 1990 to 2000 1328 meningiomas have been operated in our Neurosurgical Department. A total of 600 tumours were examined immunohistochemically using the Mib-1 monoclonal antibody. Clinical charts of the patients including surgical, histological and follow up records, as well as imaging studies were analysed retrospectively. Ki-67 LI were correlated with neuroradiological findings, 3D volumetric studies, histological subtype, recurrence-free survival, grade of resection, consistency of tumour tissue, location, osseous involvement, en plaque appearance, vascularity and progesterone-receptor status.

FINDINGS

Among the 600 patients analysed, there were 66% females (mean LI 3.8%) and 34% males (mean LI 5.7%), including 20 neurofibromatosis-type-2 (NF-II) patients with a mean LI of 5.2%. Histological grading revealed 91% WHO degrees I meningiomas (mean LI 3.28%), 7% WHO degrees II (mean LI 9.95%) and 2% WHO degrees III (mean LI 12.18%). Labelling indices in recurrent meningiomas increased from initial resection to a fourth local resection. A significant correlation between negative progesteron-receptor status and high tumour vascularity with high Ki-67 LI was seen. Ki67 was not a statistically significant predictor of survival time in totally excised WHO degrees I meningiomas.

INTERPRETATION

Mib-1 is one important tool in addition to routine histological evaluation, but a combination of clinical factors and particularly the extent of surgical resection, along with the biological features of the tumour, should influence the decision of the neurosurgeon to the patient follow up.

Loss of NF1 alleles distinguish sporadic from NF1-associated pilocytic astrocytomas

Pilocytic astrocytomas classified as WHO grade I typically arise in childhood and upon complete surgical removal carry a favorable prognosis. Children with neurofibromatosis 1 (NF1) have a vastly increased risk for pilocytic astrocytomas, especially for those of the optic nerve. Using 4 intragenic NF1 microsatellite markers, we examined losses of NF1 alleles on the long arm of chromosome 17 in 12 NF1-associated and 25 sporadic pilocytic astrocytomas. The TP53 gene region on the short arm of chromosome 17 was also examined in these tumors using 3 markers. Loss of 1 NF1 allele was detected in 11 of 12 (92%) informative NF1-associated pilocytic astrocytomas. In contrast, only 1 of 24 informative (4%) sporadic pilocytic astrocytomas exhibited allelic loss in the NF1 region. Among the 11 NF1-associated tumors with NF1 loss, 5 had also lost alleles on 17p. The high rate of NF1 allele loss in NF1-associated pilocytic astrocytomas suggests a tumor initiating or promoting action of the NF1 gene in these patients. On the other hand, the much lower rate of NF1-allele loss in sporadic pilocytic astrocytomas argues for only minor importance of NF1 in that patient group. The present data support different mechanisms in the formation of NF1-associated and sporadic pilocytic astrocytomas.

Radiation exposure to the personnel in the operating room and in the pathology due to SLN detection with Tc-99m-nanocolloid in breast cancer patients

AIM of this study was to assess the radiation exposure for the personnel in the operating room and in the pathology laboratories caused by radioguided SLN localization in breast cancer.

METHODS

In 15 patients dose rates were measured at various distances from the breast and tumor specimens during operation and pathological work-up at 3-5 h after peritumoral injection of 30 MBq Tc-99m-nanocolloid.

RESULTS

The dose rates were 84.1 +/- 46.4 microGy/h at 2.5 cm, 3.57 +/- 2.14 microGy/h at 30 cm, 0.87 +/- 0.51 microGy/h at 100 cm, and 0.40 +/- 0.20 microGy/h at 150 cm in the operating room and 44.4 +/- 27.8 microGy/h at 2.5 cm, and 1.66 +/- 1.34 microGy/h at 30 cm in the pathology laboratories. From these data the radiation exposure was calculated for 250 operations per year assuming a mean exposure time of 30 min for the surgical team members and of 10 min for the pathology staff. Under these conditions the finger dose is 10.5 mGy for the surgeon, and 5.55 mGy for the pathologist. The whole-body doses are 0.45 mSv, 0.11 mSv, 0.05 mSv, and 0.21 mSv for the surgeon, the operating room nurse, the anesthetist, and the pathologist, respectively.

CONCLUSION

Since the radiation risk to staff members is low, a classification of the personnel in the operating room and in the pathology laboratories as occupational radiation exposed workers is not necessary.

[Lymph scintigraphy and pre- and intraoperative gamma probe measurements for localization of sentinel lymph nodes (SLN) in breast cancer]

Aim of this study was to prove the clinical value of nuclear medicine procedures to detect the sentinel lymph node (SLN) for SLN biopsy.

METHODS

In 132 patients with breast cancer we performed lymph scintigraphy of the breast as well as both pre- and intraoperative gamma probe measurements correlating the results with the findings of histopathology.

RESULTS

SLN were detectable in 62 of 110 patients according to a sensitivity of 56% when scanning was performed only at 1-2 h p.i. while the sensitivity increased to 86% (19 of 22 pts.) if sequential images were acquired up to 2 h p.i. One or more SLN were identified by a hand-held gamma probe transcutaneously prior to surgery in 96% (113 of 118 pts.) of the patients who showed up with no clinically suspected lymph node metastases. Intraoperatively, in additionally 2 patients the SLN could be found resulting in a sensitivity of 97% (115 of 118 pts.). In only 3 patients with clinically no tumor spread to axillary lymph nodes no SLN could be identified by the probe. Skip lesions, i.e. lymph node metastases in patients with tumor-free SLN, occurred in 2 cases: due to SLN biopsy in these patients lymph node staging was false negative compared to conventional staging by means of axillary lymph node dissection.

CONCLUSION

The results demonstrate a high preoperative detection rate of SLN in patients with breast cancer using lymph scintigraphy and gamma probe measurements. Thus, nuclear medicine is capable of providing the basic requirements for SLN biopsy in the daily routine.

Expression of cathepsin K in chordoma

Invasive growth of chordoma is accompanied by severe destruction of adjacent bone tissue, a fact that requires high proteolytic activity at the tumor invasion fronts. In this context, cathepsin K is a candidate molecule. It is a protease with high collagenolytic and elastinolytic activity and previously thought to be restricted to osteoclasts and osteoclast-mediated bone resorption. In this study, 44 cases of chordoma of sphenooccipital localization, and 10 embryo-fetal specimens including chorda dorsalis were studied immunohistochemically for their expression of cathepsin K. In 4 additional snap-frozen chordoma cases, the enzyme expression was investigated by reverse transcription polymerase chain reaction and enzyme histochemistry. Ten chondrosarcomas of the skull base served as controls. Various concentrations of cathepsin K mRNA could be seen in all snap-frozen chordoma specimens. The protease was immunohistochemically expressed by the tumor cells. The immunoreactions were accentuated at the tumor invasion fronts. Enzyme histochemistry indicated a strong tumor cell-associated cathepsin K activity in invasive tumor components. In contrast to chordoma, cathepsin K was not significantly expressed in chorda dorsalis and chondrosarcoma of the skull base. In chondrosarcoma, protease expression was limited to osteoclastic cells localized between infiltrative tumor components and regular bone trabeculae. This study shows the significant expression and activity of cathepsin K in chordoma and implicates an important and direct role of this protease in the infiltrative growth of this tumor. This protease expression occurred during neoplastic transformation and did not appear in chorda dorsalis.

[Treatment of multilocular hepatocellular carcinoma (HCC) of 4.5 cm and 3.5 cm diameter using percutaneous ethanol injection in a patient with advanced liver cirrhosis]

Treatment of hepatocellular carcinoma (HCC) with percutaneous ethanol injection (PEI) is established for tumors up to 3 cm. We report on treatment of a multilocular HCC with a maximum size of 4.5 cm.

CASE REPORT

In a 76-year-old woman with a liver cirrhosis (Child C) due to chronic hepatitis C HCC with two nodules (diameter 3.5 cm and 4.5 cm) was diagnosed. Because of the patient's reduced general state of health and the advanced cirrhosis surgical treatment and chemoembolization were declined. The two nodules were treated in ten settings during 15 weeks under ultrasound guidance with 85 ml of 96% ethanol. There were no severe side effects. The patient's general condition improved and serum alpha-fetoprotein concentration decreased from 21,126 to 800 micrograms/l. Seven months after the diagnosis of the HCC she was admitted to another hospital due to a cerebral hemorrhage. A few days later she died because of a pneumonia. In spite of detailed micro- and macroscopically investigation no tumor was found during the autopsy. This case report shows that HCC up to a diameter of 4.5 cm can be effectively treated by PEI. This treatment modality is cheap and well-tolerated even in patients suffering from advanced cirrhosis.

Angiomyolipoma of the kidney and lymph nodes

Angiomyolipoma (AML) is a benign mesenchymal tumor predominantly occurring in the kidney. Despite its low incidence of 0.07-0.03% in an unselected population, this tumor is well known, because the typical AML can be diagnosed without histological confirmation by a combination of ultrasound (US) and computerized tomography (CT) imaging in up to 95% of cases. In contrast, simultaneous involvement of the kidney and the regional lymph nodes is less known and might be confused with metastasizing malignant tumor. We report a case of the very uncommon simultaneous involvement of the kidney and the lymph nodes in AML.

Ossified and de novo cavernous malformations in the same patient

We report the case of a 44-year-old patient with a MRI scan showing a newly developed cavernoma after two highly calcified lesions had been excised surgically. Six other cavernous malformations had been followed by MR imaging over a 2-year period. The coexistence of the two extremes of cavernous malformations in terms of lesions development--de novo and ossified lesions has not been reported previously and has implications for both the follow-up and the natural history of these malformations. The potential for developing new cavernous malformations persists and does not seem to be related to the evolutional stage of pre-existing lesions. It is suggested that these patients need to be followed up by MRI on a regular basis.

[Neurofibromatosis versus schwannomatosis]

Neurofibromatosis Type 1 and 2 (NF1 und NF2) are different forms of neurofibromatosis, well defined both clinically and genetically. In absence of typical clinical features of NF1 (café-au-lait-spots, cutaneous neurofibromas, Lisch-nodules) or NF2 (vestibular schwanoma) clinical classification is often not possible. Neurofibromas are more common in NF1 and schwannomas are typical for NF2, but pathological histology does not provide sufficient evidence for diagnosis. We describe 14 patients who presented with the clinical picture of multiple spinal tumours. Detailed family history, exact clinical examination including an ophthalmological examination led to the diagnosis of NF2 in four cases. Mutation analysis confirmed the diagnosis of NF2 in one case by identification of a 163 base pair deletion in the NF2 transcript. To investigate the expression of schwannomin and neurofibromin we stained tumour paraffin sections of six patients with antibodies against peptides of the NF1 and the NF2 protein. Based on preserved immunoreactivities we were able to exclude diagnosis of NF1 in three and NF2 in two cases. In four patients the clinical symptoms could confirm the diagnosis of schwannomatosis. Combining the results of clinical, neurogenetical and immunohistochemical examinations we could diagnose NF1 or NF2 in ten patients in total. Immunoreactivity led to the suggestion of NF2 in two patients; the other two patients whose tumours were not stained so far, could as yet not be classified for NF.

Performance evaluation of a whole-body PET scanner using the NEMA protocol. National Electrical Manufacturers Association

This study evaluates the performance of the newly developed high-resolution whole-body PET scanner ECAT EXACT HR+.

METHODS

The scanner consists of four rings of 72 bismuth germanate block detectors each, covering an axial field of view of 15.5 cm with a patient port of 56.2 cm. A single block detector is divided into an 8 x 8 matrix, giving a total of 32 rings with 576 detectors each. The dimensions of a single detector element are 4.39 x 4.05 x 30 mm3. The scanner is equipped with extendable tungsten septa for two-dimensional two-dimensional measurements, as well as with three 68Ge line sources for transmission scans and daily quality control. The spatial resolution, scatter fraction, count rate, sensitivity, uniformity and accuracy of the implemented correction algorithms were evaluated after the National Electrical Manufacturers Association protocol using the standard acquisition parameters.

RESULTS

The transaxial resolution in the two-dimensional mode is 4.3 mm (4.4 mm) in the center and increases to 4.7 mm (4.8 mm) tangential and to 8.3 mm (8.0 mm) radial at a distance of r = 20 cm from the center. The axial slice width measured in the two-dimensional mode varies between 4.2 and 6.6 mm FWHM over the transaxial field of view. In the three-dimensional mode the average axial resolution varies between 4.1 mm FWHM in the center and 7.8 mm at r = 20 cm. The scatter fraction is 17.1% (32.5%) for a lower energy discriminator level of 350 keV. The maximum true event count rate of 263 (345) kcps was measured at an activity concentration of 142 (26.9) kBq/ml. The total system sensitivity for true events is 5.7 (27.7) cps/Bq/ml. From the uniformity measurements, we obtained a volume variance of 3.9% (5.0%) and a system variance of 1.6% (1.7%). The implemented three-dimensional scatter correction algorithm reveals very favorable properties, whereas the three-dimensional attenuation correction yields slightly inaccurate results in low- and high-density regions.

CONCLUSION

The ECAT EXACT HR+ has an excellent, nearly isotropic spatial resolution, which is advantageous for brain and small animal studies. While the relatively low slice sensitivity may hamper the capability for performing fast dynamic two-dimensional studies, the scanner offers a sufficient sensitivity and count rate capacity for fully three-dimensional whole-body imaging.

Pulmonary metastasis from a basal-cell carcinoma of the retroauricular region

Basal-cell carcinoma of the skin is a common facial neoplasm, usually regarded as benign. It is also called basalioma. Distant metastasis is very rare and may involve the brain, lung, and bones. We report a 74-year-old white male who was admitted to our hospital with cough and fever. Chest radiograph revealed an opacity of 2 x 1 cm in diameter in the upper lobe of the right lung. Bronchoscopy and thoracic fine-needle aspiration could not establish a diagnosis. Therefore the patient underwent right thoracotomy and wedge excision of the lesion. Histologic evaluation was consistent with pulmonary metastasis of a facial basal-cell carcinoma. The patient recovered uneventfully from surgery and is well 5 years after the operation. According to the English literature the median survival of patients with metastatic basal-cell carcinoma is 10 months. The clinical features, pathology, and treatment of this rare entity are discussed.

Use of scanner characteristics in iterative image reconstruction for high-resolution positron emission tomography studies of small animals

The purpose of this work was to improve of the spatial resolution of a whole-body positron emission tomography (PET) system for experimental studies of small animals by incorporation of scanner characteristics into the process of iterative image reconstruction. The image-forming characteristics of the PET camera were characterized by a spatially variant line-spread function (LSF), which was determined from 49 activated copper-64 line sources positioned over a field of view (FOV) of 21.0 cm. This information was used to model the image degradation process. During the course of iterative image reconstruction, the forward projection of the estimated image was blurred with the LSF at each iteration step before the estimated projections were compared with the measured projections. The imaging characteristics of the high-resolution algorithm were investigated in phantom experiments. Moreover, imaging studies of a rat and two nude mice were performed to evaluate the imaging properties of our approach in vivo. The spatial resolution of the scanner perpendicular to the direction of projection could be approximated by a one-dimensional Gaussian-shaped LSF with a full-width at half-maximum increasing from 6.5 mm at the centre to 6.7 mm at a radial distance of 10.5 cm. The incorporation of this blurring kernel into the iteration formula resulted in a significantly improved spatial resolution of about 3.9 mm over the examined FOV. As demonstrated by the phantom and the animal experiments, the high-resolution algorithm not only led to a better contrast resolution in the reconstructed emission scans but also improved the accuracy for quantitating activity concentrations in small tissue structures without leading to an amplification of image noise or image mottle. The presented data-handling strategy incorporates the image restoration step directly into the process of algebraic image reconstruction and obviates the need for ill-conditioned "deconvolution" procedures to be performed on the projections or on the reconstructed image. In our experience, the proposed algorithm is of special interest in experimental studies of small animals.

Small cell carcinoma of the ovary, hypercalcemic type. A case report with immunohistochemical, ultrastructural and cytophotometric analysis and review of the literature

Small cell carcinomas of the ovary, hypercalcemic type, are unilateral tumors occurring almost exclusively in young women. 60% of the cases are associated with hypercalcemia. Microscopic examination shows diffuse clusters of small cells and follicle-like spaces. Immunohistochemically, the tumor cells are positive for epithelial and mesenchymal markers, and ultrastructurally they contain an abundance of dilated rough endoplasmatic reticulum and numerous free ribosomes. By DNA-single cell photometry, the neoplastic cells show a diploid DNA-content.

Percutaneous bone biopsy, techniques and indications

In the first part of this article we discuss some special technical aspects of percutaneous bone biopsy (PBB). But our main intention is to illuminate the critical indication of PBB against the background of the diagnostic and clinical utility. Reliable indications for PBB are: lytic metastases, solitary lytic lesions in a patient with known primary tumour and infection. Sclerotic metastases and vertebral compressions, on the other hand, have a lower diagnostic utility. Negative biopsies must be interpreted carefully and repeated if considered to be nonrepresentative The indication for percutaneous biopsy of primary bone tumours remains doubtful. Most of them require open biopsy.

[Oncocytoma of the nose. A case report and review of the literature]

Oncocytomas are rare epithelial tumors of the major and minor salivary glands. Reported is an oncocytoma of the lateral wall of the left nasal cavity in a 60-year-old man. Because of its locally invasive character, with rupture into the left nasal cavity and partial dedifferentiation with loss of typically oncocytic features, we classified the tumor as oncocytoma of low malignant potential.

Esthesioneuroblastomas with intracranial extension. Proliferative potential and management

A total of 15 patients with esthesioneuroblastomas were treated between 1978 and 1992 at the Neurosurgery Department, Nordstadt Hospital, Hannover. In 9 cases, the tumors invaded the anterior cranial fossa. One patient died before any surgical intervention. Eight tumors were operated by a combined paranasal and subfrontal approach. Gross total tumor removal was achieved in all cases. Apart from anosmia, the only postoperative complication was transient mental changes in one case. Immunohistochemical analyses with MIB 1 monoclonal antibodies, directed against recombinant parts of Ki-67 antigen, were performed to estimate the proliferative potential of the esthesioneuroblastomas. Most of the tumors showed high proliferating cell indexes, which ranged from 3 to 42% (mean, 16%). The proliferating cell index with MIB 1 showed a correlation with postoperative outcome, although this was not statistically significant. Esthesioneuroblastomas can be totally removed surgically. The proliferating cell index may reflect histologically the biological behavior of tumor. Long-term follow-up is mandatory, and immunohistochemical studies may be of help in predicting outcome.

Noninvasive assessment of hepatobiliary and renal elimination of cysteinyl leukotrienes by positron emission tomography

N-Acetyl-leukotriene E4 has been identified as an endogenous, biologically less active cysteinyl leukotriene metabolite in rodents and humans. To evaluate the ratio of hepatobiliary to renal elimination of leukotrienes noninvasively by positron emission tomography (PET), we synthesized N-[11C]acetyl-leukotriene E4 by chemical N-acetylation of leukotriene E4. After the intravenous injection of N-[11C]acetyl-leukotriene E4 in normal rats and monkey, uptake by the liver and subsequent excretion into bile were largely responsible for its rapid elimination from blood. In the Cynomolgus monkey, renal excretion of the leukotriene into urine was of additional quantitative importance. Kinetic modeling indicated a mean transit time through the liver of 17 minutes and 34 minutes in rat and monkey, respectively; the corresponding hepatic excretion half-times amounted to 8.5 minutes and 16 minutes. In a mutant rat strain deficient in the hepatobiliary excretion of cysteinyl leukotrienes across the canalicular membrane, the apparent mean liver transit time was 54 minutes, and the hepatic excretion half-time was 29 minutes, indicating prolonged organ storage and metabolism. After transport from the liver back into the circulating blood of omega-oxidized and beta-oxidized metabolites of N-[11C]acetyl-leukotriene E4, renal excretion compensated for the impairment of hepatobiliary elimination in the transport mutant. Metabolite analyses in urine after intravenous injection of N-[3H]acetyl-leukotriene E4 indicated the extensive inactivation of N-acetyl-leukotriene E4 by beta-oxidation from the omega-end in the mutants. A similar shift from hepatobiliary to renal cysteinyl leukotriene elimination was monitored in rats with cholestasis due to bile duct obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

[Extraneural metastasis of brain and spinal cord tumors. Report of 2 cases]

This case report refers to two patients with the rare entity of an extraneural metastasizing central nervous system tumor. The first patient presented with ipsilateral cervical lymph node metastases 4 years after a diagnostic biopsy and 2 years after removal of an anaplastic oligodendroglioma, respectively. The origin of the metastases was confirmed by immunohistochemistry. The second case described was found in a 26-year-old female who had suffered from a spinal cord pilocytic astrocytoma in infancy and been treated by surgery and radiotherapy. On postmortem examination, transformation to a primitive neuroectodermal tumor was found. Morphological and immunohistochemical features of the metastases were exactly identical with those of the primary tumors in both cases. The pathomechanisms of metastasizing CNS tumors are discussed with reference to the reasons why such cases are so rarely observed. The incidence of remote metastases and differences depending on tumor type are estimated. No relation to malignancy grade can be detected.

Neuromuscular choristoma

Neuromuscular choristomas are rare, with only 13 cases having been previously reported. They usually arise in association with large nerves, and most often occur in the first decade of life. A few have been congenital. Although resection is typically curative, in two instances partial resection alone appears to have been followed by spontaneous regression. The authors report an unusual example of an otherwise classic neuromuscular choristoma where the lesion appeared to grow after incomplete initial resection. Re-excision disclosed a fibromatosis unassociated with choristoma. Despite its wide excision, a recurrence of the fibromatosis required a forequarter amputation. Theories of histogenesis and the clinicopathologic features of the neuromuscular choristomas reported to date are reviewed. The term "benign Triton tumor," although incorrectly applied to this lesion, should be reserved for benign, true nerve sheath neoplasms exhibiting myogenic differentiation.