Pattern Of Tumor Invasion Research Articles

REAL TIME REVERSE TRANSCRIPTASE POLYMERASE CHAIN REACTION OF URINARY CYTOKERATIN 20 DETECTS TRANSITIONAL CELL CARCINOMA CELLS

We evaluate the diagnostic use of cytokeratin 20 messenger (m) RNA quantitation in urine as a marker of urothelial transitional cell carcinoma using the real time reverse transcriptase polymerase chain reaction (RT-PCR). Spontaneously voided urine was obtained from 47 patients with urothelial transitional cell carcinoma (carcinoma group), 19 other urological diseases (noncarcinoma group) and 27 healthy volunteers (control group). Quantification of cytokeratin 20 was performed with mRNA extracted from urine samples with primers and hybridization probes specific for cytokeratin 20 on a LightCycler instrument (Roche Diagnostics Corp., Indianapolis, Indiana). This method allowed reproducible quantitation of 10 to 106 cytokeratin 20 expressing colon carcinoma cells per 107 peripheral blood leukocytes, comparable to the sensitivity of conventional RT-PCR with a wide linear measuring range. Cytokeratin 20 mRNA values in the carcinoma group (mean 35,850) were significantly higher than noncarcinoma (171) and control groups (4.55, p <0.0001 and <0.0001, respectively). Urinary cytokeratin 20 mRNA values significantly correlated with tumor grade, urinary cytological class, immunostaining pattern and depth of tumor invasion. Sensitivity and specificity of real time RT-PCR with a cutoff value of 15 were 81% and 83%, whereas those of conventional cytology were 28% and 100%, respectively. These results indicate that real time cytokeratin 20 RT-PCR is a sensitive, quantitative, rapid and specific method to detect free cancer cells in the urine, with good potential for monitoring recurrence of urothelial transitional cell carcinoma.

Thymidine phosphorylase expression in oral squamous cell carcinoma

Thymidine phosphorylase (TP), as an enzyme involved in DNA synthesis, catalyzes the reversible conversion of thymidine to thymine. It is also identical to the angiogenic factor, platelet-derived endothelial cell growth factor. We examined TP expression using immunohistochemistry in 66 archival samples obtained from the patients with primary oral squamous cell carcinoma (SCC) and investigated its relation to tumor vascularity, cell proliferation, apoptosis, clinicopathological features and survival. TP expression was identified in cytonucleus and/or cytoplasm in carcinomas, but was not identified in histologically normal epithelia distant to tumor in most cases. No significant difference of microvessel density (MVD) was found between the carcinomas with high TP expression (H-TP) and low TP expression (L-TP). The percentages of proliferative cells marked by Ki-67 staining in H-TP carcinomas was significantly higher than that in L-TP carcinomas (P=0.0222). The apoptotic indice (AI) in H-TP carcinomas tended to be lower than that in L-TP carcinomas (P=0.0723). Moreover, the level of TP expression was significantly correlated the pattern of tumor invasion (P=0.0146) and marginally correlated with lymph nodal metastasis (P=0.0804). Our results suggested that TP enzyme may play a role in promotion of tumor growth in oral SCC, and that its expression can be indicative of tumor aggressiveness in this tumor type.

Thrombospondin-1 expression in oral squamous cell carcinomas: correlations with tumor vascularity, clinicopathological features and survival.

Thrombospondin-1 (TSP-1) is a 450 kd glycoprotein synthesized and incorporated into the extracellular matrix by numerous cell types and reported to suppress tumor growth and progression by its inhibition of angiogenesis. In order to clarify the biological role of TSP-1 and determine its clinicopathological significance in oral squamous cell carcinomas (SCCs), we identified TSP-1 protein expression in 54 oral SCCs by immunohistochemistry and correlated it with microvessel density (MVD), clinicopathological features and patient's survival. Thirty-two out of 54 carcinomas (59%) were identified as having a low level of TSP-1 expression (TSP-1-L), and 22/54 (41%) carcinomas identified as having a high level of TSP-1 expression (TSP-1-H). The MVD counts (mean+/-S.D.=9.0+/-4.9) in TSP-1-H tumors was significantly lower than that (mean+/-S.D.=12.7+/-4.4) in TSP-1-H tumors (P=0.0065). The level of TSP-1 expression was not correlated with T category and histologic grade, but inversely correlated with the pattern of tumor invasion (P=0.0136) and with lymph nodal status (P=0.0119). Furthermore, Kaplan-Meier analysis showed that the 5-year survival rate of TSP-1-H group was significantly higher than that of TSP-l-L group. Our results suggested that TSP-1 expression exerts an inhibitory effect on tumor vascularity, and that it has value in assessment of aggressiveness and prognosis of oral SCCs.

Histological differences in the invasion of advanced esophageal and gastric carcinoma beyond the esophago-gastric junction.

BACKGROUND: The esophago-gastric junction (EGJ) has several unique anatomical and histological features. We investigated the histological differences between esophageal squamous cell carcinoma with invasion of the gastric wall (esophageal group of patients) and gastric carcinoma with invasion of the esophageal wall (gastric group of patients).METHODS: Thirty-six patients in the esophageal group and 83 patients in the gastric group were histologically examined in regard to the mode of invasion. The pattern of tumor invasion beyond the EGJ was classified as continuous or discontinuous.RESULTS: The discontinuous pattern was more frequently seen in the esophageal group than in the gastric group. In the gastric group, however, the distance invaded beyond the EGJ was significantly greater in tumors with the discontinuous pattern than in those with the continuous pattern ( P < 0.01). Gastric mucosal invasion at the EGJ was not seen in 36% of the esophageal group, whereas tumor infiltration into the esophageal mucosal layer at the tip beyond the EGJ was found in 60% of the gastric group. The incidence of invasion deeper than the muscularis propria in the gastric and esophageal groups was 18% and 58%, respectively ( P < 0.0001).CONCLUSION: The histological characteristics of esophageal or gastric carcinoma beyond the EGJ should be taken into consideration in diagnosis and surgical procedures.

Histopathological study of the temporal bones in patients with primary carcinomas of the ear

The most common symptoms of patients with carcinomas of the middle ear or mastoid are otorrhea, facial paralysis, and hearing loss, including a sensorineural element and vertigo. The latter two symptoms are indicators of inner ear damage. However, few reports have been made concerning the histopathological changes that occur in the inner ear in the presence of a tumor. The present study was performed to determine the pattern of tumor invasion in the inner ear and the histopathological changes that occur in the inner ear in cases of ear carcinomas. Temporal bone sections from five patients (age: #39-73 years; 3 males and 2 females) who died from a primary carcinoma of the ear were studied histologically. The following features were examined: 1) localization of the tumor in the temporal bone, 2) pattern of tumor invasion in the inner ear, 3) pathological changes in the inner ear, including the cochlea, vestibule and semicircular canals. Tumor cells were still present in the temporal bone sections of all the patients except one, even though the patients had received various treatments for the carcinoma, including radiation therapy, surgery and chemotherapy. Marked inflammatory and necrotic changes were observed in cases where the tumor had invaded the external auditory canal, middle ear cleft, internal auditory canal, and in some cases the inner ear. In cases where the tumor invaded the inner ear via the internal auditory canal rather than directly from the middle ear, the otic capsule is thought to have acted as a barrier against tumor invasion. In addition, marked degenerative changes throughout the entire inner ear structures were noted. These changes may have arisen from an attenuated blood supply to the inner ear as a result of pressure from the tumor in the internal auditory canal, tumor infiltration of the labyrinthine artery.

Review of Segmental and Marginal Resection of the Mandible in Patients with Oral Cancer

This paper reviews the medical literature of the last decade to ascertain the criteria used to assess mandibular invasion by cancer of the oral cavity and to suggest how best to evaluate the mandible with a view to surgical management. It is generally agreed that patients with mandibular invasion should be treated surgically, but the extent of mandibular resection required remains a controversial matter and the accurate preoperative determination of neoplastic invasion of the mandible remains a challenge for head and neck surgeons. The relative reliability of preoperative orthopantomography, (OPG) bone scanning, computed tomography (CT) and magnetic resonance imaging (MRI), and of peroperative periosteal stripping and direct inspection in clinical assessment for mandibular surgery, is discussed. The histological patterns of tumor invasion and the most common routes of tumor entry in the mandible are described and the influence of variables such as prior radiotherapy and an edentulous vs a dentate state in relation to perineural invasion are also discussed. Finally, a comparison is drawn between the reported outcome of marginal vs segmental resection procedures and a decision-making algorithm is proposed. In selected cases, marginal mandibulectomy can ensure satisfactory tumor control, with a favorable effect on the morbidity associated with mandibular surgery.

Pattern of invasion and margin assessment in patients with oral tongue cancer.

Involvement of resection margins and the pattern of tumor invasion are reported to be important predictors of local recurrence and survival in surgically treated patients. In this study we have retrospectively assessed the significance of these two prognostic factors in a relatively homogeneous patient population. Patients and Methods This study was confined to 150 previously untreated patients who had surgery for squamous carcinoma of the oral tongue between 1987 and 1993. There were 82 men and 68 women who ranged in age from 25 to 89 years (median 60 years). Glossectomy was peroral in 129, whereas 8 and 13, respectively, had a cheek flap or mandibulotomy approach. Some form of lymphadenectomy was performed in 109 (73%), and 51 patients (34%) received postoperative radiotherapy. Histologic slides from each primary tumor were reviewed to verify the margin status. In addition, the pattern of invasion was evaluated and graded from 1 to 4, varying from a consistently well-defined, "pushing" border (Grade 1) to diffuse infiltration and cellular dissociation (Grade 4). Intraoperative frozen section assessment of margins was accurate, whether positive or negative, in 118 of 133 patients (89%). Positive or close margins (within one high-power field) and an endophytic growth pattern were associated with a significant increase in local recurrence (p <0.003 and <0.04, respectively). With higher grades of infiltration (Grade 3 or 4; 82 patients), the tumors tended to be larger and the patients younger. Although the likelihood of nodal involvement and subsequent distant metastasis was significantly greater in those with Grade 3 or grade 4 patterns (p <0.0003 and <0. 01, respectively), there was no impact on local recurrence. Cumulative survival was similar whether or not the surgical margins were involved, but was significantly reduced when the pattern of tumor invasion was of higher grade (p <0.01). Frozen section provided reasonably accurate information about margins in our patients, whether taken from the patient or the surgical specimen. Positive margins increased the likelihood of local recurrence, but did not impact on survival because subsequent surgery and/or irradiation controlled tumor recurrence in some patients. Grade 3 or 4 patterns at the tumor/host interface were associated with an increased incidence of nodal and distant metastasis, as well as a significant decrease in survival.

Management of intracranial meningiomas secondarily involving the infratemporal fossa: radiographic characteristics, pattern of tumor invasion, and surgical implications.

Intracranial meningiomas extending into the infratemporal fossa (ITF) are uncommon. This series describes the radiographic characteristics, histological pattern of invasion, and implications for surgical treatment of intracranial meningiomas. Nine patients (median age, 52 yr) underwent resection of a transcranial meningioma extending into the ITF. Five patients (56%) had undergone a previous resection; however, none had involvement of the ITF. Four patients (44%) had received prior radiation therapy to the area. Preoperative neuroradiography uniformly showed erosion of the middle fossa floor and extension of the tumor through cranial base foramina. Histological results indicated tumor invasion of the middle fossa floor and skeletal muscle in all patients. Perineural invasion was present in four patients. Mucosal invasion was observed in six patients. A middle fossa/zygomatic approach provided access to the intra- and extracranial components of the tumor, as well as the cavernous sinus, ITF structures, paranasal sinuses, and nasopharynx. Reconstruction was performed using the temporalis muscle, which provides a vascularized flap between exposed mucosa and the carotid artery and intradural structures. A gross total resection was performed in seven patients (78%). Postoperative complications included soft tissue ischemia (one patient), worsening of preoperative cranial neuropathy (two patients), and lower extremity deep vein thrombosis (two patients). One patient died 2 months postoperatively from a pulmonary embolus. Two patients had recurrence of intracranial meningiomas extending into the ITF at 2 and 3 years postoperatively, necessitating further resection. Understanding the pertinent clinical and morphological aspects of meningioma transcranially involving the ITF is essential to surgical treatment of patients with this condition.

Squamous Cell Carcinoma of the Vulva in Brazil: Prognostic Importance of Host and Viral Variables

Background. Certain clinicopathologic features of vulvar squamous cell carcinoma have been correlated with adverse prognosis. However, few large-scale studies have addressed their role in patient survival. This study examined the relationship between multiple variables and prognosis in a large group of vulvar cancers in Brazil.Methods. One hundred eighty-four Brazilian women with vulvar carcinoma were studied and the following variables recorded: age, pathologic TNM stage, survival, histologic grade, tumor histologic pattern, invasion pattern, tumor thickness, and tissue stromal and inflammatory response. Human papillomavirus (HPV) was detected by polymerase chain reaction amplification of extracted archival DNA. Data were analyzed using Cox proportional hazards modeling.Results. After controlling for age, the probability of cancer survival decreased with increasing age, stage, grade, and tumor thickness, a fibromyxoid stromal response, infiltrative growth pattern, and basaloid histologic pattern. With the exception of fibromyxoid stromal response, each of these variables remained prognostically significant after adjustment for several other predictors in a multivariate model. Women whose tumors displayed a basaloid pattern were 3.5 times as likely to die from cancer than those with keratinizing tumors [hazard ratio (HR) = 3.5, 95% CI(1.3–9.2)]. An infiltrative invasion pattern strongly increased the probability of cancer death [HR = 4.6, 95% CI(1.9,11.4)]. HPV status did not influence survival, despite its association with basaloid histology.Conclusions. Previously reported associations of negative HPV status and fibromyxoid response with adverse prognosis in vulvar cancer were not confirmed by multivariate analysis. Basaloid variants, and particularly diffusely infiltrative tumors, carry an adverse prognosis.

Prognostic value of p53 expression and histopathological parameters in squamous cell carcinoma of oral tongue.

The TNM staging system is helpful but not enough to determine prognosis of the patients with squamous cell carcinoma of the oral tongue. T-stage alone is not suggestive for prediction of occult nodal metastases. For this reason, histopathological examination of 70 patients with squamous cell carcinoma of the oral tongue was done retrospectively. The histological differentiation, tumour thickness, perineural and lymphovascular space invasions, the amount of lymphocyte infiltration and pattern of tumour invasion were examined. Immunohistochemical examination was used to determine p53 immunoreactivity as well. The effect of these histopathological parameters and p53 immunoreactivity on nodal metastases and locoregional recurrence were analyzed using the chi-squared test. In terms of nodal metastases the only statistically significant difference between the two groups was tumour thickness, either < 9 mm or > 9 mm (p < 0.05, chi 2 = 17.182). Tumour thickness, perineural invasion, lymphovascular space invasion, the amount of lymphocyte infiltration all correlated statistically with locoregional recurrence (p < 0.05, chi 2 = 6.293 for tumour thickness; p < 0.06, p = 0.054 for perineural invasion; p < 0.05, chi 2 = 8.689 for lymphovascular space invasion; p < 0.05, chi 2 = 5.320 for lymphocyte infiltration). The immunoreactivity of p53 correlated significantly with larger primary tumour size (p < 0.05, chi 2 = 5.440, lymph node metastases (p < 0.05, chi 2 = 4.093) and with pathological tumour stage (p < 0.05, chi 2 = 5.713). These results reveal that the above-mentioned histological parameters and p53 determination could be used for handling a specimen from an anterior tongue squamous cell carcinoma.

Three-dimensional reconstruction in dermatopathology--a personal computer-based system.

The purpose of the present study was to build a system for three-dimensional (3D) reconstruction of dermatopathological specimens using an easily available personal computer and graphic programs. A stereogram was generated by projecting thirty serial sections transferred into a Macintosh computer. The quality of the 3D images obtained by this method were high enough to show the net-like structure of rete ridges in normal epidermis, the antler-like branching of dermal papillae in seborrheic keratosis, and the bulge-like proliferation of tumor nests in basal cell carcinoma. This method was also helpful to assess oblique sectioning of the specimens, which sometimes produces a strange appearance in dermatopathological sections. The method presented here would not only help to better understand the 3D structures of dermatopathological specimens, but could also be used to examine 3D patterns of tumor invasion, which may contribute to the differential diagnosis of malignant tumors.

Graphic analysis of microscopic tumor cell infiltration, proliferative potential, and vascular endothelial growth factor expression in an autopsy brain with glioblastoma

BACKGROUND Growth of brain tumors requires tumor-cell attachment to adjacent structures, degradation of surrounding matrixes, migration of tumor cells, proliferation of vasculature, and tumor cell proliferation. Comparison of the findings on neuroimaging, degrees and patterns of tumor invasion, regional tumor cell viability detected by Ki-67 immunohistochemistry, and regional vascular endothelial growth factor (VEGF) expression in whole-brain specimen of glioblastoma therefore is of great interest, and will facilitate study of the host reaction against the glioblastoma. METHODS We graphically analyzed microscopic tumor-cell infiltration, regional differences in Ki-67 labeling indices (LI), and immunohistochemical expression of VEGF in an autopsy brain with glioblastoma. RESULTS Glioblastoma cells infiltrated the brain far beyond the gross limits of the tumor and the areas with high signal intensity on T2-weighted magnetic resonance images. A wide range of histologic malignancy was apparent from hematoxylin-eosin staining and the Ki-67 labeling indices. VEGF was highly expressed in normal astrocytes located outside the tumor. CONCLUSION Graphic analysis of histologic and immunohistochemical patterns is a useful method of investigating the mechanisms of glioma growth, tumor cell infiltration in the brain, and the host reaction of the brain against neoplasms.

Pattern of tumour entry and invasion of the mandible in oral squamous cell carcinoma

Pattern of tumour entry and invasion of the mandible in oral squamous cell carcinoma

Tumor invasion and angiogenesis in early esophageal squamous cell carcinoma.

Although the relationship between angiogenesis and tumor proliferation or malignant potential has been previously demonstrated in several studies, early stage of cancer invasion and angiogenesis has seldom been investigated. From the esophageal specimens of eight recently resected cases with esophageal squamous cell carcinoma, 25 areas of carcinoma-in-situ or microinvasive carcinoma were selected, and then a serial histologic investigation and immunohistochemical staining for the detection of Factor VIII-related antigen to investigate microvessels in the lamina propria mucosae beneath the lesions as a measure of angiogeneses and staining for laminin to visualize basement membrane was performed. Lymphocyte infiltration below the lesions were also estimated. In view of early cancerous invasion, histologic patterns of the growth of the lesions were divided into "flat," "expansive," and "downgrowth" patterns. Although downgrowth patterns are thought to be more invasive, relationships between the histologic patterns, and basement membrane staining patterns, and lymphocyte infiltration patterns were not demonstrated. However, the angiogenetic ratio (the number of vessels/cm under the lesions divided by that under normal epithelium) was observed to be significantly and closely related to tumor invasion patterns (P < 0.01), although it was not related to the destruction of the basement membrane or lymphocyte infiltration below the lesions. The angiogenesis of esophageal squamous cell carcinoma is closely correlated to the tumor invasion patterns in early esophageal cancerous lesions.

悪性エナメル上皮腫進展例に対する温熱放射線併用療法の応用

Thermoradiotherapy has received attention as a new therapy for malignant tumors, and its usefulness has been accepted. This paper describes the use of thermoradiotherapy for an advanced malignant ameloblastoma with lung metastasis; the outcome was good. The case was a 63-year-old man with a tumor in the left side of the mandible and neck. The tumor invaded into the skin at the left side of the neck. Judging from the pattern of tumor invasion, a radical operation was difficult, and thermoradiotherapy was performed. After therapy, the size of the tumor decreased markedly. There has been no evidence of recurrence as of one and a half years after therapy.

TRACHEOBRONCHOPLASTIC PROCEDURE FOR THE TREATMENT OF PRIMARY LUNG CANCER

Tracheobronchial reconstruction is a safe and effective procedure for patients with the neoplasms of low-grade malignancy and bronchogenic carcinoma. Thirteen patients underwent tracheobronchial reconstruction for primary lung cancer : cardinal reconstruction in 1, sleeve lobectomy in 11 and wedge lobectomy in 1. The histological type was squamous cell carcinoma in 8 patients, and each of adenocainoma, mucoepidermoid carcinoma, carcinoid tumor, adenoid cystic carcinoma and undifferentiated carcinoma in 1 including stage I in 6 patients, II in 1, III A in 4 and III B in 2. Absolutely curative operations were performed in 7 patients, relatively curative operations in 2 and absolutely non-curative operations in 4. Postoperative complications occurred in 2 patients, but both patients could be discharged. The incidence of postoperative complications in tracheobronchial reconstruction was 15.4%, and lower than among patients treated by pneumonectomy (28.9%). All of patients treated by this procedure have survived, with survival times range from 11 to 105 months. Five of them have survived for 5 years or more. Intensive follow-up is needed according to the histological type and the pattern of tumor invasion.

Factors influencing the patterns of invasion of the mandible by oral squamous cell carcinoma

The pattern of tumour invasion of the mandible depends on the extent of invasion. Both the width ( P=0.02) and depth ( P=0.01) in patients with an invasive or infiltrative pattern of disease were greater than in tumours showing the less aggressive erosive pattern in which the tumour mass is separated from the resorbing bone by a connective-tissue layer. Evidence in this study suggests that the erosive pattern develops through a mixed pattern to the invasive pattern of disease as the tumour progresses through the bone. The invasive pattern of disease was evident at a much shallower depth in the molar region of the mandible (mean 9 mm), with a decreased ratio of alveolar to basal bone, than in the premolar and parasymphyseal region (mean 25 mm) ( P=0.02). The hypothesis to explain this phenomenon is that the more superficial alveolar bone responds by resorbing in advance of the tumour, but the basal bone is unable to respond in the same way and becomes widely infiltrated. The attached mucosa with its firm collagen attachment to bone is proposed as the main route of tumour entry into the mandible in both dentate and edentulous mandibles.

Parathyroid hormone related protein in oral squamous cell carcinomas invading the mandible.

To assess parathyroid hormone related protein (PTHrP) as a candidate biochemical marker of invasion of the mandible by oral squamous cell carcinoma. Tumour PTHrP concentrations were quantitated by immunoassay, and PTHrP was detected by immunohistochemistry, in a cohort of 24 primary squamous cell carcinomas of the mandible. PTHrP was identified in all tumours examined, but no correlation was found between scores of the intensity and/or consistency of staining or tumour PTHrP concentrations and the histological classification of tumour invasion. Although PTHrP was present in all squamous tumours studied, there was no correlation between PTHrP expression and pattern of tumour invasion. However, tumour derived PTHrP may act locally to influence tumour growth and differentiation and resorption of bone.

Surgical Implications of Magnetic Resonance-enhanced Dura

The purpose of this study was to assess tissue changes responsible for dural enhancement of magnetic resonance imaging (MRI) and its clinical implications. A prospective surgical, histopathological, and MRI study was performed in 73 patients with various types of disease, including meningiomas (n = 29), craniofacial tumors with possible direct intracranial extension (n = 21), gliomas and brain metastasis in close proximity to the dura mater (n = 9), and a variety of nonneoplastic processes (n = 14). Contrast-enhanced MRI was obtained within 5 days before surgery and in some cases within 3 days after surgery as well. Histopathological examination of the dural specimens was performed in all 59 patients with neoplasia and in selected patients with nonneoplastic processes. Dural invasion was noted in 18 of 29 meningiomas, 15 of 21 craniofacial neoplasms, 3 of 5 gliomas, and 3 of 4 brain metastases. In these patients invasion was focal and in direct continuity with the tumors. MRI disclosed that dura invaded by the tumor had a break in the continuity of enhancement, or that there was no discernible enhancement. Association between patterns of dural enhancement and tumor invasion of dura was statistically significant (P < 0.001). The thickened-enhanced portion of the dura represented reactive changes. Postoperative enhancement was seen as early as 24 hours after surgery and was shown histologically to be associated with vasodilation and reactive changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical Implications of Magnetic Resonance-enhanced Dura

THE PURPOSE OF this study was to assess tissue changes responsible for dural enhancement on magnetic resonance imaging (MRI) and its clinical implications. A prospective surgical, histopathological, and MRI study was performed in 73 patients with various types of disease, including meningiomas (n = 29), craniofacial tumors with possible direct intracranial extension (n = 21), gliomas and brain metastasis in close proximity to the dura mater (n = 9), and a variety of nonneoplastic processes (n = 14). Contrast-enhanced MRI was obtained within 5 days before surgery and in some cases within 3 days after surgery as well. Histopathological examination of the dural specimens was performed in all 59 patients with neoplasia and in selected patients with nonneoplastic processes. Dural invasion was noted in 18 of 29 meningiomas, 15 of 21 craniofacial neoplasms, 3 of 5 gliomas, and 3 of 4 brain metastases. In these patients invasion was focal and in direct continuity with the tumors. MRI disclosed that dura invaded by the tumor had a break in the continuity of enhancement, or that there was no discernible enhancement. Association between patterns of dural enhancement and tumor invasion of dura was statistically significant (P < 0.001). The thickened-enhanced portion of the dura represented reactive changes. Postoperative enhancement was seen as early as 24 hours after surgery and was shown histologically to be associated with vasodilation and reactive changes. Conclusions from this study are: 1) dural enhancement is a nonspecific reaction and may be seen in association with many pathological conditions; 2) a fairly uniform “enhanced dura” adjacent to a tumor correlated with a dural inflammatory reaction, whereas discontinuous enhancing dura indicated dural invasion; 3) a few false-negative cases of dural invasion (one extracranial and four intracranial neoplasms) underscore that there are some limitations of contrast-enhanced MRI in predicting dural invasion by adjacent neoplasms.