Solid bone tumors of the spine: Diagnostic performance of apparent diffusion coefficient measured using diffusion-weighted MRI using histology as a reference standard.

PURPOSE: To assess the diagnostic performance of mean apparent diffusion coefficient (mADC) in differentiating benign from malignant bone spine tumors, using histology as a reference standard. Conventional magnetic resonance imaging (MRI) sequences have good reliability in evaluating spinal bone tumors, although some features of benign and malignant cancers may overlap, making the differential diagnosis challenging. MATERIALS AND METHODS: In all, 116 patients (62 males, 54 females; mean age 59.5 ± 14.1) with biopsy-proven spinal bone tumors were studied. Field strength/sequences: 1.5T MR system; T1 -weighted turbo spin-echo (repetition time / echo time [TR/TE], 500/13 msec; number of excitations [NEX], 2; slice thickness, 4 mm), T2 -weighted turbo spin-echo (TR/TE, 4100/102 msec; NEX, 2; slice thickness, 4 mm), short tau inversion recovery (TR/TE, 4800/89 msec; NEX, 2; slice thickness, 4 mm, IT, 140 msec), axial spin-echo echo-planar diffusion-weighted imaging (DWI) (TR/TE 5200/72 msec; slice thickness 5 mm; field of view, 300; interslice gap, 1.5 mm; NEX, 6; echo-planar imaging factor, 96; no parallel imaging) with b-values of 0 and 1000 s/mm², and 3D fat-suppressed T1 -weighted gradient-recalled-echo (TR/TE, 500/13 msec; slice thickness, 4 mm) after administration of 0.2 ml/kg body weight gadolinum-diethylenetriamine pentaacetic acid. Two readers manually drew regions of interest on the solid portion of the lesion (hyperintense on T2 -weighted images, hypointense on T1 -weighted images, and enhanced after gadolinium administration on fat-suppressed T1 -weighted images) to calculate mADC. Histology was used as the reference standard. Tumors were classified into malignant primary tumors (MPT), bone metastases (BM), or benign primary tumors (BPT). Statistical tests: Nonnormality of distribution was tested with the Shapiro-Wilk test. The Kruskal-Wallis and Mann-Whitney U-test with Bonferroni correction were used. Sensitivity and specificity of the mADC values for BM, MPT, and BPT were calculated. Approximate receiver operating characteristic curves were created. Interobserver reproducibility was evaluated using the intraclass correlation coefficient (ICC). RESULTS: The mADC values of MPT (n = 35), BM (n = 65), and BPT (n = 16) were 1.00 ± 0.32 (0.59-2.10) × 10-3 mm2 /s, 1.02 ± 0.25 (0.73-1.96) × 10-3 mm2 /s, 1.31 ± 0.36 (0.83-2.14) × 10-3 mm2 /s, respectively. The mADC was significantly different between BPT and all malignant lesions (BM+MPT) (P < 0.001), BM and BPT (P = 0.008), and MPT and BPT (P = 0.008). No difference was found between BM and MPT (P = 0.999). An mADC threshold of 0.952 × 10-3 mm2 /s yielded 81.3% sensitivity, 55.0% specificity. Accuracy was 76% (95% confidence interval [CI] = 63.9%-88.1%). Interobserver reproducibility was almost perfect (ICC = 0.916; 95% CI = 0.879-0.942). CONCLUSION: DWI with mADC quantification is a reproducible tool to differentiate benign from malignant solid tumors with 76% accuracy. The mADC values of BPT were statistically higher than that of malignant tumors. However, the large overlap between cases may make mADC not helpful in a specific patient. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1034-1042.

Plasmacytoma of the thoracic spine with intracellular amyloid and massive extracellular amyloid deposition.

A 65-year-old woman presented with back pain and a lytic destructive lesion of T-11. Fine-needle aspiration biopsy revealed a granulomatous reaction with unusual signet ring type cells and vacuolated histiocytes. Subsequent resection of the lesion revealed a fibrohistiocytic reaction with extensive amyloid deposition. Immunoperoxidase stains confirmed monotypic kappa light-chain staining. Ultrastructural examination of paraffin-embedded tissue confirmed extracellular amyloid deposition. A unique feature of this case was the finding of intracellular amyloid; the unusual signet ring cells were shown to be plasma cells with intracellular amyloid, and the vacuolated histiocytes also contained amyloid.

A neuroendocrine cause of oncogenic osteomalacia.

All definite cases of oncogenic osteomalacia have, until now, been classified as mesenchymal tumours. We report here a case of oncogenic osteomalacia caused by a spinal tumour. Microscopically, it resembled the mixed connective tissue variant of previously described phosphaturic tumours. Immunohistochemical studies, however, showed the tumour cells to be positive for low molecular weight cytokeratin (CAM 5.2), S100 protein, PGP 9.5, and synaptophysin. Electron microscopy demonstrated neurosecretory granules. The histopathological findings strongly suggest that this is a neuroendocrine tumour.

[An immunohistochemical and ultrastructural study of 20 chordomas].

Altogether 20 chordomas were reported. The site distribution included 9 cases at the sacrococcygeal region, another 9 cases at the spheno-occipital region, 1 at the cervical vertebra, and another 1 at the lumbar vertebra. Histologic examination revealed that characteristic "physaliphorous cells" were easily identified in all the 19 cases. Tissue for immunohistochemistry study was available in 18 cases. Among them, tumor cells were found strongly positive to EMA, but negative for CEA. 16/18 cases also showed positive for keratin and S-100 protein. Totally, 2 cases were studied ultrastructurally and there were abundant RER and microfilaments seen in the cytoplasm of the tumor cells but only few surface microvilli detected. The epithelial nature of chordoma is strongly supported by the ultrastructural and immunohistochemical findings of these 20 cases.

Spindle cell neoplasm of the thoracic spine.

The case is a 56-year-old woman who presented with cord compression from a lesion of the thoracic spine. Histologic analysis confirmed the diagnosis of a spindle cell sarcoma. Ultrastructural analysis showed features characteristic of a leiomyosarcoma. Subsequent discussion with the patient revealed a history of hysterectomy performed for fibroid uterus 5 years before the current presentation. Review of the previous surgical specimen confirmed the presence of a leiomyosarcoma originally interpreted as a large infarcted myoma.

Extramedullary blast crisis in chronic myelogenous leukemia. Demonstration of T-cell lineage and Philadelphia chromosome in a paraspinal tumor.

A case of chronic myelogenous leukemia (CML) with penetrance of the Ph1 molecular alteration into the T-cell lineage of a paraspinal tumor is reported. The T-cell nature of the paraspinal tumor was documented by immunochemical study and genotyping. The Philadelphia chromosome was also detected by genotyping in the same tumor cell population. To the authors' knowledge, this is the first case of extramedullary T-cell blast crisis in CML demonstrated in an extranodal tumor. The clinical significance of detecting extramedullary blast crisis, and the theories for the scarcity of T-cell transformation in CML are discussed.

Microtubular aggregates in the rough endoplasmic reticulum of sacrococcygeal chordoma.

A tumor with the light microscopic and immunohistologic characteristics of chordoma in the sacrococcygeal region in a 48-year-old man was examined by electron microscopy and immunohistochemistry for tubulin. A large population of cells exhibited prominent parallel arrays of long, straight microtubules in the rough endoplasmic reticulum in addition to the well-described ultrastructural features of chordoma. Immunoreaction to tubulin recognized in the juxtanuclear regions of the large number of tumor cells was in accordance with the ultrastructural localization of the microtubular aggregates. This seems to be the first report of microtubular aggregations in rough endoplasmic reticulum in classic chordoma. Furthermore, the present electron microscopic and immunohistochemical findings suggest that tubulin is a constituent of the unusual structures.

Extraspinal ependymoma in the sacrococcygeal region. A case report with ultrastructural, immunohistochemical and cytophotometric studies.

We describe on a primary, subcutaneous sacrococcygeal ependymoma presenting in a young female patient. Detailed immunohistochemical and electron microscopic examinations were performed. Out of the 40 similar cases reported in literature this is the first in which the determination of DNA content was also used to predict biological behaviour. The tumour proved to be aneuploid with low proliferative capacity in spite of absent histological signs of malignancy. It is suggested that DNA determination may be helpful in establishing prognosis and that it may contribute to a better understanding of the biological behaviour of this tumour.

Dumb-bell ganglioneuroma of the spine misinterpreted as progressive idiopathic scoliosis. Case report.

A giant ganglioneuroma generating a progressive scoliosis in a 16-year-old girl is presented. The interval between the start of the orthopaedic treatment and the diagnosis of the true nature of the disease was more than 4 years, thus allowing the development of a giant partly intracanalicularly partly retroperitonealy expanding tumor mass. The report emphasizes and describes the combined neurosurgical, general surgical and orthopaedic surgical treatment and presents the results of light- and electron microsopical, immunohistochemical and quantitative neurochemical investigations of the resected tumor.

Cytologic, cytochemical, immunocytochemical and ultrastructural diagnosis of a sacrococcygeal chordoma in a fine needle aspiration biopsy specimen.

The cytologic, cytochemical, immunocytochemical and ultrastructural findings on the aspirated material are presented for the case of a 57-year-old man with sacrococcygeal chordoma diagnosed by fine needle aspiration biopsy. Cytologically, two types of cellular elements were differentiated: medium-sized cells with few cytoplasmic vacuoles and classic physaliferous cells. Both types showed marked cytoplasmic positivity for keratin and S-100 protein; the absence of nuclear positivity in the physaliferous cells was notable. Ultrastructural study demonstrated the existence of true intracytoplasmic vacuoles and frequent rough endoplasmic reticulum-mitochondria complexes. The cytologic differential diagnosis with chondrosarcoma, myxoid liposarcoma, ependymoma and metastases of mucosecretory carcinomas is reviewed.

Malignant rhabdoid tumor of the thoracic spine.

A case of malignant rhabdoid tumor of the spine and a description of its CT findings are presented. The CT demonstrated a heterogeneous contrast enhancing epidural mass associated with severe bony destruction of the adjacent vertebra and cord compression.

Hemangiopericytomas of the spinal canal. Report of four cases and review of literature.

The Authors report four cases of spinal hemangiopericytomas. The diagnosis has been ascertained by electron microscopy. Despite the malignant nature, the association of surgery and radiotherapy is interesting in that it prolongs the survival rate. Clinical, neuroradiological, microscopic and ultrastructural features of intraspinal hemangiopericytomas are evaluated in the light of the review of the relevant literature.

Traumatic fascicular neuroma.

A 72-year-old man had developed amiodarone neuropathy. He was found, at biopsy, to have a fascicular neuroma of his right sural nerve, unassociated with his underlying neuropathy, apparently due to blunt trauma, as electroneurographic needling of this nerve could safely be ruled out by the patient and his physicians. Such fascicular neuromas, which may remain without sensory deficits, may develop at an unknown frequency, and may only be uncovered by biopsy--or autopsy--in a coincidental neuropathic process.

[Chordomas]. / Chordomes.

Chordomas are slowly growing malignant tumors arising from notochordal rests. They are occurring in adults (50 to 60 year old) and are mainly (85%) located in sacrococcygeal or spheno-occipital regions; other main localization is cervical spine. Chordomas are usually discovered in patients with pain or symptoms due to compression of surrounding viscera. Radiologically it is characterized by association of osteolysis and soft tissues opacity. On macroscopic examination tumoral tissue has mucoid appearance; under microscope it is made up with lobules of epithelial-appearing cells surrounded by acid mucosubstances. Tumorous cells contain glycogen and neutral mucosubstances. They are surrounded by argyrophilic rim due to pericellular condensation of intercellular matrix, well viewed on electron microscope examination. When their cytoplasm is filled with vacuoles, cells take up typical physaliphorous appearance. Chordomas cells express epithelial differentiation antigens (low molecular weight cytokeratins, EMA, CAM 52, HFM 62, even CEA), Vimentin and S-100 Protein: this triple positivity allow differentiation between chordomas and numerous others tumors. Correct treatment of chordoma is achieved with an initially complete excision. Local recurrences are frequent and sometimes inoperable: in this cases radiotherapy alone may be performed (70 grays). Sarcomas (fibroblastic or Malignant fibrous histiocytoma) may occur after radiotherapy or without it. Hematogenous metastasis occur in 10% to 15% of patients. Survival rate at five years is included between 50% and 75%. Chondroid chordoma is a special entity occurring in younger patients (35 year old) and located in spheno-occipital region. In addition to chordomas it contain chondroid (benign or malignant) islands. Mean survival rate (16 years) is far better than for chordoma or chondrosarcoma.

Chordomas in Fischer 344 rats.

Tissue sections and records of 56 rats with chordoma, identified in the National Toxicology Program's (NTP) data base of approximately 115,000 rats, were examined to determine morphological characteristics, incidence, and aspects of biological behavior. Chordomas occurred in aged rats, originated predominantly in lumbosacral vertebrae, were highly malignant, occurred three times more often in male versus female rats, and commonly produced bilateral posterior paresis, paralysis, and/or distention of the colon and rectum.

Spinal granular cell tumor with subarachnoid hemorrhage: case report.

A granular cell tumor in the spinal canal that presented with subarachnoid hemorrhage is reported. The tumor was totally excised. The pathogenic and clinical aspects are discussed.

Experimental neoplastic spinal cord compression: evoked potentials, edema, prostaglandins, and light and electron microscopy.

Spinal cord compression was induced in Fischer rats by percutaneous inoculation of 10(6) cells of malignant fibrous histiocytoma anterior to the T13 vertebral body. Paraplegia and incontinence occurred in all animals after 14-27 days (median, 23 +/- 3.0 days). Autonomic dysfunction and a measurable increase in tumor volume were documented with the use of computer tomography. The tumor penetrated the vertebral bone, invaded the epidural space, and gradually compressed the lumbar spinal segments. Electron-microscopic examination revealed dilated intermyelin spaces containing exuded homogenous material and extravasated leukocytes and erythrocytes. Myelin breakdown was accompanied by the presence of lipid-laden macrophages. Sequential recording of somatosensory evoked potentials (SEP) revealed a progressive increase in the latency of the cervical responses, which preceded the onset of clinical signs. In the presence of paraplegia, spinal cord conductivity was abolished. The levels of the prostaglandins TXB2, 6-keto-PGF1 alpha, and PGE2 were measured in the compressed and remote spinal cord segments during the presymptomatic and symptomatic periods. Only PGE2 was significantly elevated (P less than 0.001) in the paraplegic rats, all along the spinal cord segments. A significant increase in water content was measured in the compressed lumbar segments in the presymptomatic period, and when paralysis set in it was increased in the adjacent low thoracic area as well. Tissue specific gravity was significantly increased only in paraplegic rats in the compressed (P less than 0.01) and the adjacent low thoracic areas (P less than 0.05) but no significant change occurred during the presymptomatic period. Multiple mechanisms play a role in the pathogenesis of neurologic symptoms in neoplastic spinal cord compression.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuroblastoma presenting as a paravertebral mass and painful scoliosis in a 21-year-old woman.

Idiopathic scoliosis is a disease of unknown etiology. It presents in growing children, progresses slowly with time, and is painless. Any variation from the usual presentation warrants investigation. Extra dural pressure, tethering of the cord, tumors, and progressive neurologic lesions must be excluded as causative factors.