Tumor Mimics Research Articles

Spinal Primitive Neuroectodermal Tumor Mimicking as Chronic Inflammatory Demyelination Polyneuropathy

We report a young boy who presented with progressive weakness of lower extremities associated with areflexia and abnormal electrophysiological findings initially suggestive of chronic inflammatory demyelinating polyneuropathy. Initial lumbosacral spinal magnetic resonance imaging (MRI) showed thickened descending spinal nerve roots only. Immunomodulating therapy was given but with limited clinical response. Repeated spine magnetic resonance imaging showed cauda equina and also new spinal cord extramedullary contrast enhancement. The initial extensive investigations including open biopsy did not point to any specific diagnosis. Only through pursuing a repeated biopsy, the diagnosis of the spinal peripheral primitive neuroectodermal tumor was confirmed. This case highlights the diagnostic challenges of the spinal peripheral primitive neuroectodermal tumor that could have an initial chronic inflammatory demyelinating polyneuropathy-like presentation. The literature review confirms that this is a rare condition and cauda equina origin has only been reported in adults and teenagers, and this is the first reported case in a young child.

Prostate-Specific Antigen-Retargeted Recombinant Newcastle Disease Virus for Prostate Cancer Virotherapy

Oncolytic virus (OV) therapies of cancer are based on the use of replication-competent, tumor-selective viruses with limited toxicity. Newcastle disease virus (NDV), an avian paramyxovirus, is a promising OV and is inherently tumor selective and cytotoxic only to tumor cells. Replication is restricted in normal cells. Despite encouraging phase I/II clinical trials with NDV, further refinements for tumor-specific targeting are needed to enhance its therapeutic index. Systemically delivered NDV fails to reach solid tumors in therapeutic concentrations and also spreads poorly within the tumors due to barriers including complement, innate immunity, and the extracellular matrix. Overcoming these hurdles is paramount to realizing the exceptional oncolytic efficacy of NDV. We engineered the F protein of NDV and generated a recombinant NDV (rNDV) whose F protein is cleavable exclusively by prostate-specific antigen (PSA). The rNDV replicated efficiently and specifically in prostate cancer (CaP) cells and 3-dimensional prostaspheres but failed to replicate in the absence of PSA. Induction of intracellular PSA production by a synthetic androgen analog (R1881) enhanced fusogenicity in androgen-responsive CaP cells. Further, PSA-cleavable rNDV caused specific lysis of androgen-independent and androgen-responsive/nonresponsive CaP cells and prostaspheres, with a half-maximal effective concentration (EC50) ranging from a multiplicity of infection of 0.01 to 0.1. PSA-retargeted NDV efficiently lysed prostasphere tumor mimics, suggesting efficacy in vivo. Also, PSA-cleavable NDV failed to replicate in chicken embryos, indicating no pathogenicity for chickens. Prostate-specific antigen targeting is likely to enhance the therapeutic index of rNDV owing to tumor-restricted replication and enhanced fusogenicity.

胃癌術後再発との鑑別を要した腹腔内デスモイド腫瘍の2例

胃癌術後再発との鑑別を要した腹腔内デスモイド腫瘍の2例

Gliosis Versus Glioma?

A major challenge in the routine practice of surgical neuropathology is the distinction between reactive astrocytosis, which may be because of non-neoplastic and neoplastic conditions, and a low-grade infiltrating diffuse astrocytoma [World Health Organization (WHO) grade II]. This can be particularly challenging with small biopsies that often yield limited amounts of tissue for pathologic study, especially considering the marked differences in prognosis and therapy after a pathologic diagnosis. This paper will review some basic principles of gliosis as an astrocytic reaction to a wide range of central nervous system insults and focus on some common diagnostic pitfalls such as (1) gliosis associated with brain tumor mimics, including demyelinating disease and infections, (2) gliosis associated with nonglial tumors such as craniopharyngioma, hemangioblastoma, metastases, and central nervous system lymphoma. New diagnostic methods have facilitated the differentiation between reactive astrocytosis and the diffuse gliomas. Of these, the use of mutated isocitrate dehydrogenase-1 (IDH-1) as a marker of diffuse infiltrating astroctomas, oligodendrogliomas, and a subset of glioblastomas (secondary glioblastomas) is particularly exciting for tissue diagnosis and patient prognosis. In addition IDH-1 may be useful to distinguish a diffuse infiltrating glioma from low-grade "focal" neoplasms such as the pilocytic astocytoma in histologically ambiguous cases. The discovery of BRAF mutations as molecular signatures of some pilocytic astrocytomas, gangliogliomas, and pleomorphic xanthoastrocytomas has provided another diagnostic tool for the pathologist. Only after a definitive diagnosis of a diffuse infiltrating glioma or a focal glioma is made should a tumor grade be applied and some practical issues in current glioma grading are provided.

In Vivo Evaluation of Lung Microwave Ablation in a Porcine Tumor Mimic Model

To evaluate the microwave ablation of created tumor mimics in the lung of a large animal model (pigs), with examination of the ablative synergy of multiple antennas. Fifty-six tumor-mimic models of various sizes were created in 15 pigs by using barium-enriched minced collected thigh muscle injected into the lung of the same animal. Tumors were ablated under fluoroscopic guidance by single-antenna and multiple-antenna microwaves. Thirty-five tumor models were treated in 11 pigs with a single antenna at 75W for 15min, with 15 measuring 20mm in diameter, 10 measuring 30mm, and 10 measuring 40mm. Mean circularity of the single-antenna ablation zones measured 0.64±0.12, with a diameter of 35.7±8.7mm along the axis of the antenna and 32.7±12.8mm perpendicular to the feeding point. Multiple-antenna delivery of 75W for 15min caused intraprocedural death of 2 animals; modified protocol to 60W for 10min resulted in an ablation zone with a diameter of 43.0±7.7 along the axis of the antenna and 54.8±8.5mm perpendicular to the feeding point; circularity was 0.70±0.10 A single microwave antenna can create ablation zones large enough to cover lung tumor mimic models of ≤4cm with no heat sink effect from vessels of ≤6mm. Synergic use of 3 antennas allows ablation of larger volumes than single-antenna or radiofrequency ablation, but great caution must be taken when 3 antennas are used simultaneously in the lung in clinical practice.

Imaging quiz: tumours and tumour mimics

Imaging quiz: tumours and tumour mimics

Imaging Review of Skeletal Tumors of the Pelvis Malignant Tumors and Tumor Mimics

Malignant lesions of the pelvis are not uncommon and need to be differentiated from benign lesions and tumor mimics. Appearances are sometimes nonspecific leading to consideration of a broad differential diagnosis. Clinical history, anatomic location, and imaging characterization can help narrow the differential diagnosis. The focus of this paper is to demonstrate the imaging features and the role of plain films, computed tomography, and magnetic resonance imaging for detecting and characterizing malignant osseous pelvic lesions and their common mimics.

Advanced magnetic resonance imaging biomarkers of cerebral metastases

There are a number of magnetic resonance imaging techniques available for use in the diagnosis and management of patients with cerebral metastases. This article reviews these techniques, in particular, the advanced imaging methodologies from which quantitative parameters can be derived, the role of these imaging biomarkers have in distinguishing metastases from primary central nervous system tumours and tumour mimics, and metrics that may be of value in predicting the origin of the primary tumour.

Gastritis Cystica Profunda: A Rare Gastric Tumor Masquerading as a Malignancy

Introduction: Gastritis cystica profunda (GCP) is a rare tumor which occurs more commonly in patients with prior gastric surgery. The nonspecific symptoms and radiographic appearance of this tumor mimic that of other hyperproliferative conditions making diagnosis difficult without definitive surgical resection. This report provides a comprehen-sive review of GCP and all GCP cases reported to date. Methods: A comprehensive literature search (1972-2011) was conducted with all reported GCP cases analyzed. Keywords searched included gastritis cystica profunda, submucosal cysts of the stomach, and heterotopic submucosal gastric glands. Results: Thirty-seven GCP cases have been reported since 1972, which includes 29 (78%) men and 8 (21%) women (M:F ratio, 3.6:1). The overall mean age was 60.5 years (range, 39 - 81 years) with 55.6 years (range, 39 - 79) and 62.2 years (range, 39 - 81 years) in women and men, respectively. 65% (N = 24) had prior gastric surgery. 62% (N = 23) of GCP tumors were located in the body; 24% (N = 9) in the fundus; 8% (N = 3) in the antrum; or 6% (N = 2) in the cardia of the stomach. GCP was an incidental finding in 19% of patients. Complete excision was performed most often (73%) followed by endomucosal resection (18%), and polypectomy (4.5%). One patient underwent surveillance (4.5%). Conclusions: GCP is a rare gastric tumor, which is difficult to diagnose preoperatively and masquerades as a malignancy. GCP is more common in men and typically presents with nonspecific symptoms. Although a benign lesion, GCP may represent an intermediate histology in the malignant progression to gastric neoplasia. To date, there have been no reports of local recurrence or distant metastasis following definitive surgical excision, which remains the standard of care.

Initial laboratory experience with a novel ultrasound probe for standard and single‐port robotic kidney surgery: increasing console surgeon autonomy and minimizing instrument clashing

The aim of this study was to evaluate a novel ultrasound probe specifically developed for robotic surgery by determining its efficiency in identifying renal tumors. The study was carried out using the Da Vinci™ surgical system in one female pig. Renal tumor targets were created by percutaneous injection of a tumor mimic mixture. Single-port and standard robotic partial nephrectomy were performed. Intraoperative ultrasound was performed using both standard laparoscopic probe and the new ProART™ Robotic probe. Probe maneuverability and ease of handling for tumor localization were recorded. The standard laparoscopic probe was guided by the assistant. Significant clashing with robotic arms was noted during the single-port procedure. The novel robotic probe was easily introduced through the assistant trocar, and held by the console surgeon using the robotic Prograsp™ with no registered clashing in the external operative field. The average time for grasping the new robotic probe was less than 10 s. Once inserted and grasped, no limitation was found in terms of instrument clashing during the single-port procedure. This novel ultrasound probe developed for robotic surgery was noted to be user-friendly when performing porcine standard and especially single-port robotic partial nephrectomy.

A 32-Year-Old Man With Recurrent Kidney Stones and an Abnormal Chest Radiograph

A 32-Year-Old Man With Recurrent Kidney Stones and an Abnormal Chest Radiograph

Injectable self-assembled block copolymers for sustained gene and drug co-delivery: An in vitro study

A temperature-responsive pentablock copolymer (PB) was designed to deliver DNA and provide prolonged gene expression by forming a thermogelling release depot after subcutaneous or intratumoral injection. A synthetic barrier gel was developed based on poly(ethylene glycol) diacrylate to enable the released vectors to instantly and continuously transfect cultured cells. The aim of this setup was to provide a simple and controlled in vitro system to mimic tumor matrix to optimize the release system and to study the influence of the continuous and sustained release of the polyplexes on the in vitro transfection. The porosity of the barrier gel was adjusted by addition and removal of Pluronic F127 (PL), and the properties of the gel were characterized by visual inspection and scanning electron microscopy (SEM). Concentrated PB-based vector was administered to the barrier gel and allowed to be released to the buffer. We found that most of feed vector could be released from the barrier gel without unpacking the polymer–DNA complexes. Based on the specific construction of the PB-based vectors, an anti-cancer drug paclitaxel (PTX) was further loaded into the same vector designed for DNA delivery, thus formulating a gene and drug co-delivery system. This system was tested for sustained delivery to human ovarian carcinoma cells SKOV3 using the barrier gel in vitro as a tumor mimic. Transfection efficiency was found to be significantly enhanced by co-delivering PTX, while PTX also showed its effect as an anti-cancer drug to induce cell death. Yet both of the two effects of PTX shown in SKOV3 cells turned out to be dramatically weaker in ARPE-19 cells, a human non-cancerous cell line, which might be related to the nature of the vector itself. Instant release of vectors showed the ability to maintain transfection up to the fourth day, making the gene expression stable at least for the first 5 days. Further study is still needed to improve the duration of effective release.

Development of Hepatic Pseudotumors for Image-guided Interventional and Surgical Research in a Large Animal Model

Purpose Real-time image guidance and navigation have become increasingly important in an era of minimally invasive interventional and surgical procedures in the liver. To develop, test, and implement tools for real-time image guidance, the authors sought to create an in vivo tumor mimic with realistic imaging and treatment capabilities. Materials and Methods Hepatic pseudotumors were created by injecting 1–2 mL of alginate (a hydrocolloid) directly into the liver parenchyma in eight live pigs and two dog cadavers. Tumors were imaged by B-mode ultrasound (US), US elasticity imaging, multi–detector row computed tomography (CT), CT fluoroscopy, and magnetic resonance (MR) imaging to assess imaging capabilities. Procedures performed with the alginate pseudotumors included radiofrequency (RF) ablation and robotic needle guidance. Results Twenty-four hepatic pseudotumors were created, ranging in size from 10 mm to 28 mm at an average depth of 6 mm. Average time of preparation and insertion was 3 minutes. All tumors were palpable under the surface of the liver and were easily visible on B-mode US, US elasticity imaging, CT, and MR imaging. Tumors were successfully “treated” with RF ablation, and gross examination of the liver showed good encompassment of the tumor by the zone of thermal coagulation. In addition, the pseudotumors allowed for easy introduction of various types of needles, including RF ablation probes and experimental steerable needles. Conclusions Alginate pseudotumors can easily be imaged and allow for different procedures to be performed. This model can be used for various research purposes.

Part 2: CT characterisation of pancreatic neoplasm: tumour mimics

There are numerous pancreatic and peripancreatic conditions that can mimic pancreatic neoplasms. Many of these can be confidently diagnosed on computed tomography (CT), while others will require further imaging. Knowledge of these tumour mimics is important to avoid misclassification of benign conditions as malignant and to avoid unnecessary surgery. Mimics can be grouped as parenchymal, vascular, biliary and peripancreatic. These are discussed and illustrated in this review.

Isolated Epithelioid Trophoblastic Tumor Mimicking Non-small Cell Lung Cancer

Isolated Epithelioid Trophoblastic Tumor Mimicking Non-small Cell Lung Cancer

Phenotypic Diversity in Chondromyxoid Fibroma Reveals Differentiation Pattern of Tumor Mimicking Fetal Cartilage Canals Development: An Immunohistochemical Study

Chondromyxoid fibroma represents a rare benign cartilaginous tumor of young patients occurring in a subcortical metaphyseal location. The histogenesis of chondromyxoid fibroma has not yet been postulated, even though the conventional histology and recent immunohistochemical studies on phenotype of the mesenchymal cells and extracellular matrix components suggested its origin in immature cartilage. Therefore, we wished to compare the morphological pattern of immature cartilage tissue with chondromyxoid fibroma to investigate a possible developmental counterpart of chondromyxoid fibroma. Archival paraffin-embedded tissues from 4 fetal femora and 10 cases of chondromyxoid fibroma were analyzed simultaneously using histochemistry (safranin O) and established immunohistochemical antibodies (CD34, CD163, and smooth muscle actin). Vascularized cartilage canals growing into the fetal cartilage from the perichondrium displayed characteristic glomeruloid structures with central arterioles within the immature mesenchymal stroma and numerous superficial sinusoidal blood vessels accompanied by macrophage infiltration. Similarly, each case of chondromyxoid fibroma demonstrated admixture of two characteristic components: immature fibrous tissue of vascularized stroma with accumulation of macrophages in areas of superficial sinusoidal proliferation, and variable amounts of lobulated chondroid tissue. Based on the observed substantial morphological similarity between the cartilage canals and chondromyxoid fibroma, we suggest that the chondromyxoid fibroma represents a neoplasm originating from or mimicking the fetal cartilage canals within the immature cartilage.

In vivo preclinical evaluation of the accuracy of toroidal-shaped HIFU treatments using a tumor-mimic model

The pig is an ideal animal model for preclinical evaluation of HIFU treatments, especially in the liver. However, there is no liver tumor model available for pigs. In this work, we propose to study an in vivo tumor-mimic model as a tool for evaluating if a sonographycally guided HIFU treatment, delivered by a toroidal-shaped device dedicated for the treatment of liver metastases, is correctly located in the liver. One centimeter tumor-mimics were created in liver tissues. These tumor-mimics were detectable on ultrasound imaging and on gross pathology. Two studies were carried out. First, an in vivo study of tolerance at mid-term (30 days, 10 pigs) revealed that tumor-mimics are suitable for studying HIFU treatments at a preclinical stage, since local and biological tolerances were excellent. The dimensions of the tumor-mimics were reproducible (diameter at day 0: 9.7 ± 2.0 mm) and were the same as a function of time (p = 0.64). A second in vivo study was carried out in ten pigs. Tumor mimics were used as targets in liver tissues in order to determine if the HIFU treatment is correctly located in the liver. A procedure of extensive HIFU ablation using multiple HIFU lesions juxtaposed manually was then tested on eight tumor-mimics. In 88% of the cases (seven out of eight), tumor-mimics were treated with negative margins (⩾1 mm) in all directions. On average, negative margins measured 10.0 ± 6.7 mm. These tumor-mimics constitute an excellent reference for studying in vivo the accuracy of HIFU therapy in the liver.

Third Prize: Synchronized Real-Time Ultrasonography and Three-Dimensional Computed Tomography Scan Navigation During Percutaneous Renal Cryoablation in a Porcine Model

To investigate the accuracy of percutaneous cryoablation for kidney tumors performed under combined real-time ultrasonography (US) and three-dimensional (3D) CT scan navigation in a porcine model. After percutaneously injecting 2 to 6 tumor mimic lesions in 11 pigs, a CT scan was performed and digital data were saved into a navigation system (Real-Time Virtual Sonography [RVS]) that allows 3D reconstruction and synchronization with real-time US images. The cryoprobe was guided percutaneously into the kidney tumor mimic, and ice ball formation was monitored continuously during cryoablation using the RVS system. Kidneys were harvested and sent for gross pathologic and histopathologic analysis at days 0, 15, and 30 postoperatively. Thirty-five renal tumor mimics were created and treated by percutaneous cryotherapy; tumor mimic locations were as follows: 16 tumors (46%) in the lower pole, 14 (40%) in the central region, and 5 (14%) in the upper pole. Eleven tumor mimics (31%) were intraparenchymal, and 24 (69%) subcapsular. The synchronization between the CT scan 3D reconstructed images and real-time US was successful in all cases. The mean tumor size was 2 cm (range, 1.2-4 cm). Mean cryonecrosis size was 3.3, 3.7, and 2.8 cm at days 0, 15, and 30, respectively. Three (8.5%) positive margins were found on the macroscopic and microscopic analysis. RVS imaging system synchronizing real-time US with preoperative CT scan is a feasible and safe technique for percutaneous probe ablation of kidney tumors.

Pseudoneoplasms of the Nervous System

Pseudoneoplasms of the nervous system vary greatly in nature. Ranging from inflammatory to autoimmune, infectious, malformative, reactive, degenerative, and radiation induced, they all mimic true tumors. Thus, they have the potential to mislead clinicians, radiologists, and pathologists alike. Their clinical and/or neuroimaging and histologic features are readily misinterpreted as tumor. Knowledge of the pitfalls is essential to avoid mismanagement, specifically overtreatment. In such instances, pathologists must take the entire clinical picture into consideration, acquainting themselves with presenting symptoms, physical findings, and neuroimaging. To present 10 examples of pseudoneoplasms of the nervous system, analyze the basis for their mimicry, and discuss their differential diagnosis. Review of the pertinent literature related to pseudoneoplasms of the nervous system and review of the consultation files of one of the authors (B.W.S.). The identification of tumor mimics may be difficult under the best of circumstances, and maintaining a broad differential diagnosis as well as application of a variety of immunocytochemical and occasionally ultrastructural and/or molecular genetic methods is essential to arrive at a correct diagnosis.

Percutaneous Radiofrequency Lung Ablation Combined with Transbronchial Saline Injection: An Experimental Study in Swine

To evaluate the efficacy of radiofrequency lung ablation with transbronchial saline injection. The bilateral lungs of eight living swine were used. A 13-gauge bone biopsy needle was inserted percutaneously into the lung, and 1 ml of muscle paste was injected to create a tumor mimic. In total, 21 nodules were ablated. In the saline injection group (group A), radiofrequency ablation (RFA) was performed for 11 nodules after transbronchial saline injection under balloon occlusion with a 2-cm active single internally cooled electrode. In the control group (group B), conventional RFA was performed for 10 nodules as a control. The infused saline liquid showed a wedge-shaped and homogeneous distribution surrounding a tumor mimic. All 21 RFAs were successfully completed. The total ablation time was significantly longer (13.4 +/- 2.8 min vs. 8.9 +/- 3.5 min; P = 0.0061) and the tissue impedance was significantly lower in group A compared with group B (73.1 +/- 8.8 Omega vs. 100.6 +/- 16.6 Omega; P = 0.0002). The temperature of the ablated area was not significantly different (69.4 +/- 9.1 degrees C vs. 66.0 +/- 7.9 degrees C; P = 0.4038). There was no significant difference of tumor mimic volume (769 +/- 343 mm(3) vs. 625 +/- 191 mm(3); P = 0.2783). The volume of the coagulated area was significantly larger in group A than in group B (3886 +/- 1247 mm(3) vs. 2375 +/- 1395 mm(3); P = 0.0221). Percutaneous radiofrequency lung ablation combined with transbronchial saline injection can create an extended area of ablation.