Metastatic melanoma: correlation of MRI characteristics and histopathology

How to update esophageal masses imaging using literature review (MRI and CT features)

MRI offers new opportunities for detailed visualization of the different layers of the esophageal wall, as well as early detection and accurate characterization of esophageal lesions. Staging of esophageal tumors including extramural extent of disease, and status of the adjacent organ can also be performed by MRI with higher accuracy compared to other imaging modalities including CT and esophageal endoscopy. Although MDCT appears to be the primary imaging modality that is indicated for preoperative staging of esophageal cancer to assess tumor resectability, MDCT is considered less accurate in T staging. This review aims to update radiologists about emerging imaging techniques and the imaging features of various esophageal masses, emphasizing the imaging features that differentiate between esophageal masses, demonstrating the critical role of MRI in esophageal masses. CRITICAL RELEVANCE STATEMENT: MRI features may help differentiate mucosal high-grade neoplasia from early invasive squamous cell cancer of the esophagus, also esophageal GISTs from leiomyomas, and esophageal malignant melanoma has typical MR features. KEY POINTS: MRI can accurately visualize different layers of the esophagus potentially has a role in T staging. MR may accurately delineate esophageal fistulae, especially small mediastinal fistulae. MRI features of various esophageal masses are helpful in the differentiation.

Primary malignant melanoma of the parotid gland, a rare case arising from a duct: a case report and literature review

Malignant melanoma of the parotid gland is an unusual tumor in the head and neck region, and most parotid melanoma is reported as a metastatic lesion of cutaneous malignant melanoma. We report a case of primary malignant melanoma arising in the parotid gland duct with diagnostic challenge. The patient was a 68-year-old man who complained of repeated right facial swelling that presented 3 months prior. Swelling was detected along the Stensen's duct of the cheek, and brown-colored saliva-like fluid was aspirated. On MR and CT images, a fluid-filled duct with small nodule and heterogeneously enhancing mass in the parotid parenchyma was detected. The nodular mass on the ductal wall grew rapidly, and the hyperintense T1 signal became significant on follow-up images. The final diagnosis via histopathologic examination using biopsy and parotidectomy specimen revealed the lesion as malignant melanoma of the duct and pleomorphic adenoma of the parenchyma. Even if the incidence of primary malignant melanoma is very low among tumors occurring in the parotid gland, efforts supporting an early diagnosis using imaging characteristics are important.

Melanoma in pregnancy

Melanoma is one of the most common types of cancer diagnosed during pregnancy. Patients with advanced disease require frequent staging examinations (e.g., CT, PET, MRI, ultrasound), which, during pregnancy must be modified from routine protocol to minimize risk to the fetus. We will review the diagnostic and treatment approach to pregnant patients with melanoma, with a discussion and pictorial examples of imaging protocol modifications, and the appearance of metastatic melanoma on radiology exams using modified protocols due to pregnancy.

Diffusion-weighted imaging hyperintensities during the chronic stage of intracerebral hemorrhage with surgery: A new clinical situation or post-surgery artifact?

Background and objective

Diffusion-weighted imaging (DWI) hyperintensities were occasionally seen at previous hematoma in patients several months after intracerebral hemorrhage with surgery. Whether they are newly occurred clinical situations or post-surgery changes is unknown. This study aims to investigate the prevalence and possible mechanisms for this phenomenon.

Methods

We retrospectively reviewed the MRI database for intracerebral hemorrhage with surgery after 3 months of disease onset in our hospital. We also prospectively performed repeated multimodal MRI scans for two patients at the chronic stage after surgery for intracerebral hemorrhage.

Results

We found that 14 out of 23 patients (60.9%) had DWI hyperintensities at the site of previous hematoma 3 months after intracerebral hemorrhage with surgery. All the DWI lesions were hyperintense on T1- and T2-weighted imaging, most of which appeared long and narrow in shape. The DWI lesions were usually located adjacent to the thin wall of the previous hematoma cavity close to the lateral ventricle. They were more associated with the basal ganglia hemorrhage than with the lobar hemorrhage (P = 0.02) and were more frequently seen for those with intraventricular hemorrhage than without (P = 0.02). Prospectively repeated MRI exams of two patients revealed unchanged DWI hyperintensity during the 18- and 2-month follow-up, respectively.

Conclusion

The DWI lesions at previous hematoma were commonly seen in patients after surgery for intracerebral hemorrhage at the chronic stage which would persist for years. We hypothesized a possible mechanism by which extracellular methemoglobin “islands” are formed with delayed or no absorption by macrophages from adjacent thin residual brain tissue. Unnecessary further examinations and treatment would be avoided by realizing this imaging phenomenon.

Multidisciplinary management of spinal metastases: what the radiologist needs to know

The modern management of spinal metastases requires a multidisciplinary approach that includes radiation oncologists, surgeons, medical oncologists, and diagnostic and interventional radiologists. The diagnostic radiologist can play an important role in the multidisciplinary team and help guide assessment of disease and selection of appropriate therapy. The assessment of spine metastases is best performed on MRI, but imaging from other modalities is often needed. We provide a review of the clinical and imaging features that are needed by the multidisciplinary team caring for patients with spine metastases and stress the importance of the spine radiologist taking responsibility for synthesizing imaging features across multiple modalities to provide a report that advances patient care.

Noncontrast-enhanced 3-Tesla MRI using surface coil as a complementary test for assessment of distribution and depth of locoregional cutaneous metastases of malignant melanoma

Locoregional and distant metastases account for most cases of morbidity and mortality associated with melanoma. In addition, local recurrences of melanoma might be the onset of disseminated disease. Therefore, precise diagnosis and therapy are warranted to minimize morbidity and increase survival in a subset of patients. However, the correct distribution of the metastatic lesions on the skin is often difficult to estimate. We present the application of noncontrast-enhanced 3-Tesla MRI using surface coil to detect locoregional cutaneous metastases of malignant melanoma on the basis of the topographic assessment of skin lesions. Furthermore, in a systematic review, we summarize the current knowledge about application of MRI in assessment of location, distribution, and depth of cutaneous primary malignant melanoma. MRI might be applied to evaluate the location, distribution, size, and depth of the locoregional cutaneous metastasis of malignant melanoma to identify the optimal cost-effective treatment strategies and monitor their effects.

Evaluation and Management of Acute Myelopathy

Acute myelopathies are spinal cord disorders characterized by a rapidly progressive course reaching nadir within hours to a few weeks that may result in severe disability. The multitude of underlying etiologies, complexities in confirming the diagnosis, and often unforgiving nature of spinal cord damage have always represented a challenge. Moreover, certain slowly progressive myelopathies may present acutely or show abrupt worsening in specific settings and thus further complicate the diagnostic workup. Awareness of the clinical and magnetic resonance imaging characteristics of different myelopathies and the specific settings where they occur is fundamental for a correct diagnosis. Neuroimaging helps distinguish compressive etiologies that may require urgent surgery from intrinsic etiologies that generally require medical treatment. Differentiation between various myelopathies is essential to establish timely and appropriate treatment and avoid harm from unnecessary procedures. This article reviews the contemporary spectrum of acute myelopathy etiologies and provides guidance for diagnosis and management.

Charcoal Heart: Metastatic Melanoma Mimicking Right Atrial Myxoma

A 59-year-old woman with history of skin melanoma and complete excision presented with palpitations. Transthoracic echocardiogram revealed right atrial mass attached to interatrial septum. Cardiac magnetic resonance was suggestive of metastatic melanoma. Laboratory tests revealed elevated liver enzymes. Liver ultrasonography showed a large mass positive for metastatic melanoma by biopsy. (Level of Difficulty: Intermediate.).

Single shot echo planar imaging (ssEPI) vs single shot turbo spin echo (ssTSE) DWI of the orbit in patients with ocular melanoma

OBJECTIVES

Diffusion weighted imaging (DWI) has become important for orbital imaging. However, the echoplanar imaging (EPI) DWI has inherent obstacles due to susceptibility to magnetic field inhomogeneities. We conducted a comparative study assessing the image quality of orbits in a patient cohort with uveal melanoma (UM). We hypothesized that single shot turbo spin echo (ssTSE) DWI would have better image quality in terms of less distortion and artifacts and yield better tissue evaluation compared to ssEPI-DWI.

METHODS

ssEPI-DWI and ssTSE-DWI of orbits were obtained from 50 patients with uveal melanoma who were prospectively enrolled in the study. Distortion ratio (DR), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), diffusion signal properties, and apparent diffusion coefficient (ADC) values were collected and compared between ssEPI-DWI and ssTSE-DWI. Two reviewers evaluated and compared the geometric distortion, susceptibility and ghosting artifacts, resolution, demarcation of ocular mass, and overall quality.

RESULTS

A higher DR was found in ssEPI-DWI compared to ssTSE-DWI (p < 0.001). SNR and CNR were lower for the temporal lobe cortex (p ≤ 0.004), but higher for melanoma in ssEPI-DWI than ssTSE-DWI (p ≤ 0.037). Geometric distortion and artifacts were more common in ssEPI-DWI (p < 0.001). Resolution (p ≤ 0.013) and overall quality (p < 0.001) were better in ssTSE-DWI. Ocular masses were demarcated better on ssEPI-DWI (p ≤ 0.002). Significant negative correlations between T1 and T2 signal intensities (r = -0.369, p ≤ 0.008) and positive correlations between T2 and both DWI signal intensities (r = 0.686 and p < 0.001 for ssEPI-DWI, r = 0.747 and p < 0.001 for ssTSE-DWI) were revealed.

CONCLUSION

With less geometric distortion and susceptibility artifacts, better resolution, and overall quality, ssTSE-DWI can serve as an alternative to ssEPI-DWI for orbital DWI.

ADVANCES IN KNOWLEDGE

ssTSE-DWI can be a better alternative of diffusion imaging of orbits with less susceptibility artifact and geometric distortion compared to ssEPI-DWI.

Disorders of neural crest derivates in oncoradiological practice

Hundreds of articles discuss the imaging characteristics and molecular background of prominent gastrointestinal (GI) motility disorders and tumors of the peripheral nervous system, but according to our knowledge an article focusing on the classification and developmental background of these heterogeneous diseases is not to be found. Our aim is to give insight on the common features of several diseases and tumors, starting with their common source of origin, the neural crest (NC). The NC is a transient cell population of the embryo, which differentiates into several organs/structures of our body (sympathetic trunk, adrenal medulla). Although the incidence of the individual tumors of NC cells is not high by themselves, the summation of these incidences may be relevant in the daily routine. In the introduction we mention the most prominent developmental routes and molecular pathways of NC cells, which is crucial to understand the pathogenesis and the wide range of involved cell types from the colon to the adrenal gland. We summarized the most important, useful pathological findings and imaging techniques from the X-ray to the positron emission tomography—computed tomography (CT) in order to help the identification of these diseases. This article may help to better understand NC lineage and its unique, diverse role during ontogeny, which may influence the radiologists to change several convictions, or understand better the background and/or connections of a wide range of tumors and syndromes.

Differentiating melanoma and healthy tissues based on elasticity-specific Brillouin microspectroscopy

The main objective of the present study is to evaluate the use of Brillouin microspectroscopy for differentiation of melanoma and normal tissues based on elasticity measurements. Previous studies of malignant melanoma show that the lesion is stiffer than the surrounding healthy tissue. We hypothesize that elasticity-specific Brillouin spectroscopy can be used to distinguish between healthy and cancerous regions of an excised melanoma from a Sinclair miniature swine. Brillouin measurements of non-regressing and regressing melanomas and the surrounding healthy tissues were performed. Based on the Brillouin measurements, the melanomas and healthy tissues can be successfully differentiated. The stiffness of both tumors is found to be significantly greater than the healthy tissues. Notably, we found that the elasticity of regressing melanoma is closer to that of the normal tissue. The results indicate that Brillouin spectroscopy can be utilized as a tool for elasticity-based differentiation between malignant melanoma and surrounding healthy tissue, with potential use for melanoma boundary identification, monitoring tumor progression, or response to treatment.

JOURNAL CLUB: Primary Anorectal Melanoma: MRI Findings and Clinicopathologic Correlations

OBJECTIVE

The purpose of this study is to evaluate the MRI features of primary anorectal malignant melanoma and to correlate these features with its clinical and pathologic characteristics.

MATERIALS AND METHODS

The medical records of 12 patients (five men and seven women; mean age [± SD], 60.8 ± 10.0 years) with pathologically proven primary anorectal melanoma were retrospectively reviewed. MRI findings were analyzed to determine the shape, size, distance from the anal verge, presence of perirectal or anal infiltration, signal intensity on T1- and T2-weighted images, presence of diffusion restriction, contrast enhancement pattern of the lesion, presence of lymphadenopathy, and occurrence of bowel obstruction. Subsequent follow-up data for the patients were recorded.

RESULTS

The most common presentation was hematochezia (41.7% of patients). Common findings on MRI included a large intraluminal polypoid mass (75.0% of lesions) with little perirectal or anal infiltration (100.0%), T1 hyperintensity (66.7%), high T2 signal intensity (54.5%) or mixed T2 signal intensity (45.5%), restricted diffusion (100.0%), and hyper-enhancement (100.0%). The mean length, width, and depth of these masses were 3.5, 2.9, and 2.3 cm, respectively. The mean distance from the anal verge was 1.8 cm. Lymphadenopathy was frequently identified (75.0% of cases), with lymph nodes larger than 2 cm noted in 28.5% of cases and most commonly involving the perirectal area (77.8% of cases). No colonic obstructions were observed. The mean patient follow-up was 32.7 months. A total of 25.0% of patients died as a result of disease progression.

CONCLUSION

The possibility of the presence of anorectal melanoma should be considered for patients with a bulky intraluminal polypoid mass in the anorectum without colonic obstruction, with the mass showing T1 hyperintensity, high or mixed signal T2 intensity, hyperenhancement, minimal perirectal or anal infiltration, and lymphadenopathy.

Dynamic contrast-enhanced MRI coupled with a subtraction technique is useful for treatment response evaluation of malignant melanoma hepatic metastasis

PURPOSE

To determine whether contrast-enhanced MRI including subtraction sequences can predict the treatment response of melanoma liver metastasis.

RESULTS

High precontrast T1 signal intensity (SI) of melanoma lesions obscured detection of enhancement after contrast injection. It was impossible to determine whether or not enhancement occurred in the majority of lesions (85.4%, n = 35/41) without including the subtraction technique. Positive enhancement was identified in 14.6% (n = 6/41) of patients without subtraction images, but increased to 68.3% (n = 28/41) by including subtraction images. Follow-up studies determined lesion progression in 34.1% (n = 14/41) of patients. Positive enhancement on the subtraction image (odds ratio = 12.1, P = 0.048) and intermediate high T2 SI (odds ratio = 8.16, P = 0.040) were significantly associated with higher risk of lesion progression.

MATERIALS AND METHODS

Patients who underwent MRI for melanoma liver metastases between January 2007 and February 2015 were enrolled. The study analyzed 41 liver metastases in 15 patients [11 male and four female; median age 56 years (range 21-81)] for size, lesion enhancement with and without subtraction images, and T2 SI. Follow-up imaging studies were used to determine treatment response. Data were analyzed with generalized estimating equations.

CONCLUSIONS

MRI including the subtraction technique is useful for determining the treatment response of melanoma liver metastases. Lesion contrast enhancement and intermediate high T2 SI increased the risk of lesion progression.

Splenic Involvement in Disseminated Mycobacterium avium-intracellulare Infection: Magnetic Resonance Imaging Findings

We report the imaging findings of a patient with disseminated Mycobacterium avium-intracellulare complex presenting with multiple splenic lesions incompletely characterized on computed tomography in whom magnetic resonance imaging helped narrow the differential diagnosis. We discuss the magnetic resonance imaging findings suggesting the diagnosis, including the presence of focal susceptibility artifact within the lesions (ie, signal drop on T1 in-phase imaging), marked hypointensity on diffusion-weighted imaging, and faint progressive peripheral enhancement after contrast administration. We provide pathologic correlation to explain these imaging characteristics and a review of the literature of imaging characteristics in splenic involvement of M. avium-intracellulare complex infection.

Ex vivo tissue imaging for radiology-pathology correlation: a pilot study with a small bore 7-T MRI in a rare pigmented ganglioglioma exhibiting complex MR signal characteristics associated with melanin and hemosiderin

To advance magnetic resonance imaging (MRI) technologies further for in vivo tissue characterization with histopathologic validation, we investigated the feasibility of ex vivo tissue imaging of a surgically removed human brain tumor as a comprehensive approach for radiology–pathology correlation in histoanatomically identical fashion in a rare case of pigmented ganglioglioma with complex paramagnetic properties. Pieces of surgically removed ganglioglioma, containing melanin and hemosiderin pigments, were imaged with a small bore 7-T MRI scanner to obtain T1-, T2-, and T2*-weighted image and diffusion tensor imaging (DTI). Corresponding histopathological slides were prepared for routine hematoxylin and eosin stain and special stains for melanin and iron/hemosiderin to correlate with MRI signal characteristics. Furthermore, mean diffusivity (MD) maps were generated from DTI data and correlated with cellularity using image analysis. While the presence of melanin was difficult to interpret in in vivo MRI with certainty due to concomitant hemosiderin pigments and calcium depositions, ex vivo tissue imaging clearly demonstrated pieces of tissue exhibiting the characteristic MR signal pattern for melanin with pathologic confirmation in a histoanatomically identical location. There was also concordant correlation between MD and cellularity. Although it is still in an initial phase of development, ex vivo tissue imaging is a promising approach, which offers radiology–pathology correlation in a straightforward and comprehensive manner.

Molecular imaging probes for multi-spectral optoacoustic tomography

In this review, we discuss recent progress in emerging optoacoustic probes, their mechanisms, applications and challenges for biological imaging using MSOT.

Identification of an Immunogenic Subset of Metastatic Uveal Melanoma

PURPOSE

Uveal melanoma is a rare melanoma variant with no effective therapies once metastases develop. Although durable cancer regression can be achieved in metastatic cutaneous melanoma with immunotherapies that augment naturally existing antitumor T-cell responses, the role of these treatments for metastatic uveal melanoma remains unclear. We sought to define the relative immunogenicity of these two melanoma variants and determine whether endogenous antitumor immune responses exist against uveal melanoma.

EXPERIMENTAL DESIGN

We surgically procured liver metastases from uveal melanoma (n = 16) and cutaneous melanoma (n = 35) patients and compared the attributes of their respective tumor cell populations and their infiltrating T cells (TIL) using clinical radiology, histopathology, immune assays, and whole-exomic sequencing.

RESULTS

Despite having common melanocytic lineage, uveal melanoma and cutaneous melanoma metastases differed in their melanin content, tumor differentiation antigen expression, and somatic mutational profile. Immunologic analysis of TIL cultures expanded from these divergent forms of melanoma revealed cutaneous melanoma TIL were predominantly composed of CD8(+) T cells, whereas uveal melanoma TIL were CD4(+) dominant. Reactivity against autologous tumor was significantly greater in cutaneous melanoma TIL compared with uveal melanoma TIL. However, we identified TIL from a subset of uveal melanoma patients which had robust antitumor reactivity comparable in magnitude with cutaneous melanoma TIL. Interestingly, the absence of melanin pigmentation in the parental tumor strongly correlated with the generation of highly reactive uveal melanoma TIL.

CONCLUSIONS

The discovery of this immunogenic group of uveal melanoma metastases should prompt clinical efforts to determine whether patients who harbor these unique tumors can benefit from immunotherapies that exploit endogenous antitumor T-cell populations. Clin Cancer Res; 22(9); 2237-49. ©2015 AACR.

Melanoma-targeted delivery system (part 1): design, synthesis and evaluation of releasable disulfide drug by glutathione

Here we describe the design and synthesis of a prodrug developed for pigmented melanoma therapy, consisting of a Melanin-Targeting Probe (MTP) conjugated to 5-iodo-2'-deoxyuridine (IUdR) with a reduction-sensitive pre-determined breaking point. Compared with the non-cleavable conjugate (17b), prodrug (17a) bearing a self-immolative disulfide linker achieved complete release of IUdR within 20 min in the presence of reducing agents such as DTT or glutathione. Analytical results also showed that prodrug (17a) was more sensitive than parent non-cleavable conjugate (17b) for a concentration range of glutathione similar to that found in the intracellular compartment of tumours.

Cardiac metastatic melanoma: Imaging diagnostic clues

A 47-year-old male was admitted to hospital for severe pericardial effusion; he had undergone surgical removal of cutaneous melanoma 10 years before. Echocardiography-guided pericardiocentesis revealed the presence of intramyocardial masses, which were better defined and characterized, together with pericardial involvement, by cardiac magnetic resonance. Pericardial fluid drained was negative for malignant cells, so video-assisted thoracoscopy was performed and pathologic tissue was biopsied, leading to the diagnosis of metastatic melanoma. Multidisciplinary approach and multimodality imaging played a key role in allowing the diagnostic workup in this complex case. <Learning objective: The diagnosis of cardiac metastases is challenging and histologic characterization is necessary to guide therapy. Multimodality imaging and minimally invasive thoracoscopy are key tools to achieve these goals.>.

Histologic validation of locus coeruleus MRI contrast in post-mortem tissue

The locus coeruleus (LC) noradrenergic system regulates arousal and modulates attention through its extensive projections across the brain. LC dysfunction has been implicated in a broad range of neurodevelopmental, neurodegenerative and psychiatric disorders, as well as in the cognitive changes observed during normal aging. Magnetic resonance imaging (MRI) has been used to characterize the human LC (elevated contrast relative to surrounding structures), but there is limited understanding of the factors underlying putative LC contrast that are critical to successful biomarker development and confidence in localizing nucleus LC. We used ultra-high-field 7 T magnetic resonance imaging (MRI) to acquire T1-weighted microscopy resolution images (78 μm in-plane resolution) of the LC from post-mortem tissue samples. Histological analyses were performed to characterize the distribution of tyrosine hydroxylase (TH) and neuromelanin in the scanned tissue, which allowed for direct comparison with MR microscopy images. Our results indicate that LC-MRI contrast corresponds to the location of neuromelanin cells in LC; these also correspond to norepinephrine neurons. Thus, neuromelanin appears to serve as a natural contrast agent for nucleus LC that can be used to localize nucleus LC and may have the potential to characterize neurodegenerative disease.

Ipilimumab and whole brain radiation therapy for melanoma brain metastases

Brain metastases (BM) frequently develop in patients with melanoma and are associated with a poor prognosis. Whole brain radiation therapy (WBRT) is a standard intervention for intracranial disease, particularly in patients with multiple BM. Ipilimumab improves survival in patients with advanced melanoma. The purpose of this study is to investigate the safety and efficacy of concurrent WBRT and ipilimumab. A retrospective analysis was conducted of 13 consecutive patients treated with WBRT within 30 days of ipilimumab administration. Radiographic response, as measured by serial magnetic resonance imaging scans post-treatment, was graded by modified World Health Organization (mWHO) and immune-related response criteria (irRC) in the 9 patients with follow-up imaging. Treatment-related toxicity was prospectively assessed during treatment. Four of nine patients (44 %) experienced partial response or stable central nervous system (CNS) disease as measured by mWHO criteria. This number increased to 5 patients (56 %) when irRC criteria were used. Rates of treatment-related neurologic toxicity were low with only one patient experiencing grade 3-4 neurologic toxicity. There was a high rate of intratumoral hemorrhage in this patient population, with 10 of 10 patients with post-treatment imaging demonstrating new or increased intratumoral bleeding after WBRT. This retrospective study demonstrates that the primary pattern of CNS response to WBRT and ipilimumab is stable disease and not regression of BM. Furthermore, while the combination of WBRT and ipilimumab may offer promising efficacy, prospective studies are needed to further assess efficacy and toxicity.

Electron paramagnetic resonance: a powerful tool to support magnetic resonance imaging research

The purpose of this paper is to describe some of the areas where electron paramagnetic resonance (EPR) has provided unique information to MRI developments. The field of application mainly encompasses the EPR characterization of MRI paramagnetic contrast agents (gadolinium and manganese chelates, nitroxides) and superparamagnetic agents (iron oxide particles). The combined use of MRI and EPR has also been used to qualify or disqualify sources of contrast in MRI. Illustrative examples are presented with attempts to qualify oxygen sensitive contrast (i.e. T1 - and T2 *-based methods), redox status or melanin content in tissues. Other areas are likely to benefit from the combined EPR/MRI approach, namely cell tracking studies. Finally, the combination of EPR and MRI studies on the same models provides invaluable data regarding tissue oxygenation, hemodynamics and energetics. Our description will be illustrative rather than exhaustive to give to the readers a flavour of 'what EPR can do for MRI'.

Development of gadolinium based nanoparticles having an affinity towards melanin

Small Rigid Platforms (SRPs) are sub-5 nanometre gadolinium based nanoparticles that have been developed for multimodal imaging and theranostic applications. They are composed of a polysiloxane network surrounded by gadolinium chelates. A covalent coupling with quinoxaline derivatives has been performed. Such derivatives have proven their affinity for melanin frequently expressed in primary melanoma cases. Three different quinoxaline derivatives have been synthesised and coupled to the nanoparticles. The affinity of the grafted nanoparticles for melanin has then been shown in vitro by surface plasmon resonance on a homemade melanin grafted gold chip.

Vaccinia virus-mediated melanin production allows MR and optoacoustic deep tissue imaging and laser-induced thermotherapy of cancer

We reported earlier the delivery of antiangiogenic single chain antibodies by using oncolytic vaccinia virus strains to enhance their therapeutic efficacy. Here, we provide evidence that gene-evoked production of melanin can be used as a therapeutic and diagnostic mediator, as exemplified by insertion of only one or two genes into the genome of an oncolytic vaccinia virus strain. We found that produced melanin is an excellent reporter for optical imaging without addition of substrate. Melanin production also facilitated deep tissue optoacoustic imaging as well as MRI. In addition, melanin was shown to be a suitable target for laser-induced thermotherapy and enhanced oncolytic viral therapy. In conclusion, melanin as a mediator for thermotherapy and reporter for different imaging modalities may soon become a versatile alternative to replace fluorescent proteins also in other biological systems. After ongoing extensive preclinical studies, melanin overproducing oncolytic virus strains might be used in clinical trials in patients with cancer.

Metastatic melanoma to the heart

Melanoma is a common neoplasm with a propensity to metastasize to the heart. Although cardiac metastasis is rarely diagnosed ante mortem, using a multimodality approach, several imaging findings may be seen. Echocardiography is often the initial imaging method used to detect cardiac metastases and their complications. On computed tomography, intraluminal filling defects and myocardial/pericardial nodules may be seen. On magnetic resonance imaging, metastatic melanoma is classically hyperintense on T1 images and hypointense on T2 images, a result of the T1 shortening of melanin; however, this is seen in a minority of cases. As melanoma metastases are fluorine-18-fluorodeoxyglucose avid, fluorine-18-fluorodeoxyglucose positron emission tomography may also be used to detect cardiac metastases.

Skeletal Metastasis

The most commonly diagnosed tumor in the skeleton represents metastatic disease. Metastatic carcinoma should be the first consideration in older patients with atypical radiologic findings or clinical features suggestive of a bone lesion. The primary goal in the setting of skeletal metastasis is usually palliation.

Bevacizumab-induced tumor calcifications as a surrogate marker of outcome in patients with glioblastoma

Therapy-induced calcifications in glioblastoma are rarely recognized. They may represent regressive changes in the tumor tissue, but their occurrence and possible predictive or prognostic value have not been systematically assessed. The observation of hyperintense lesions on precontrast T1-weighted magnetic resonance images (MRIs) in 2 index patients with glioblastoma after therapy with bevacizumab, subsequently identified as calcifications on computed tomographs (CTs), prompted us to prospectively screen for these radiographic changes. Therefore, 36 patients with recurrent glioblastoma prospectively treated with bevacizumab in an observational trial were examined every 8 weeks by MRI and, if clinically necessary, by CT. In 22 patients (61.1%), T1 hyperintense lesions became apparent after bevacizumab treatment. The median time to detection of these lesions was 55 days. In 14 (63.6%) of 22 patients, CTs were available and confirmed the existence of tumor calcifications. No substantial changes in T1 hyperintense lesions or calcifications were recognized on additional MRI or CT scans. Interestingly, the patients with therapy-induced T1 hyperintense lesions had better durations of progression-free survival than patients without these changes (median, 5.8 vs 3.5 months; P< .001), and the duration of overall survival was also superior (median, 9.7 vs 5.0 months; P= .006). There was a striking correlation between the appearance of therapy-induced T1 hyperintense lesions and overall response to bevacizumab. Therefore, this phenomenon is a rather early and time-limited event during the first weeks of treatment and appears to be response related. In summary, T1 hyperintense lesions are common in patients with glioblastoma who have been exposed to bevacizumab, may represent a novel biomarker of response and outcome, and seem to correspond to tumor calcifications.

In vivo magnetic resonance imaging to detect malignant melanoma in adult zebrafish

Zebrafish cancer models are fast gaining ground in cancer research. Most tumors in zebrafish develop late in life, when fish are no longer transparent, limiting in vivo optical imaging methods. Thus, noninvasive imaging to track tumor in adult zebrafish remains challenging. In this study, we applied magnetic resonance microimaging (microMRI) to track spontaneous melanomas in stable transgenic zebrafish models expressing an RAS oncoprotein and lacking P53 (mitf:Ras::mitf:GFP X p53(-/-)). Tumors in live adult zebrafish were observed at various locations using a T(2)-weighted fast spin echo sequence at 9.4 T. Further, live imaging of tumors at ultrahigh field (17.6 T) revealed significant tumor heterogeneity. This heterogeneity was also confirmed by the significant differences in transverse relaxation time, T(2) measured in various regions of tumor. To our knowledge, this is the first report demonstrating the application of microMRI to detect the locations, invasion status, and characteristics of internal melanomas in zebrafish and suggesting that noninvasive microMRI can be applied for longitudinal studies to track tumor development and real-time assessment of therapeutic effects in zebrafish tumor models.

Preoperative staging of liver metastases from uveal melanoma by magnetic resonance imaging (MRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET)

BACKGROUND

Microscopically complete (R0) resection of metastases from uveal melanoma prolongs median overall survival compared to incomplete surgery. The aim of this study was to compare the sensitivity of dynamic-enhanced magnetic resonance imaging (MRI) with fluorodeoxyglucose-positron emission tomography (FDG-PET) in the preoperative diagnosis of liver metastases from uveal melanoma.

PATIENTS AND METHODS

Fifteen consecutive patients (mean age: 56 years) underwent FDG-PET and liver MRI. Extrahepatic metastatic disease was excluded by whole body computed tomography and bone scintigraphy. MRI and FDG-PET were performed with a mean of 19 days (range: 1-30) before surgery. Imaging findings were compared with surgical (including intraoperative ultrasonography) and histological findings on a lesion by lesion analysis.

RESULTS

R0 resection was performed in 12 patients. A total of 28 lesions were resected with 27 histologically proven metastases. Nine lesions were smaller than 5mm, 7 measured 5-10mm and 11 were larger than 10mm. Sensitivity and positive predictive value were 67% and 95% for MRI compared to 41% and 100% for FDG-PET. The difference between the two modalities was statistically significant (p=0.01; McNemar test). In remaining 3 patients, diffuse miliary disease (>10 capsular lesions) was discovered intraoperatively, and was suspected on preoperative MRI in 2 cases. Only one extrahepatic lesion identified by FDG-PET was falsely positive.

CONCLUSIONS

In this preliminary study, MRI was superior to FDG-PET for staging of liver metastases from uveal melanoma. Although miliary disease was suggested by MRI in some cases, preoperative confirmation remains imperfect.

Cardiovascular magnetic resonance of the charcoal heart

We report a case of malignant melanoma metastasis to the heart presenting as complete heart block. The highlight of the case is to demonstrate that silent cardiac metastasis is not uncommon and CMR has the potential to characterize these cardiac metastases and should be used routinely as a screening tool for those cancers with a high chance of cardiac involvement.

Magnetic resonance screening trial for hepatic metastasis in patients with locally controlled choroidal melanoma

OBJECTIVE

The aim of the present study was to evaluate the value of magnetic resonance (MR) screening for detection of hepatic metastasis in patients with locally controlled choroidal melanoma.

METHODS

MR examinations were performed after an initial diagnosis of choroidal melanoma in 159 patients (mean age 56 years: range, 10-86 years). The MR follow-up interval was 5.2 +/- 1.7 years (range, 1.2-6.6 years). A total of 363 MR studies were reviewed by two radiologists for predominant signal intensity characteristics. Hepatic metastasis was verified by histological examination: tumor resection and CT-guided needle biopsy specimens and/or on the basis of an obvious progression in number and/or size of the lesions on the follow-up MR examination.

RESULTS

The majority of patients underwent MR examinations from one to three times (n = 126, 79%). During a mean follow-up period of 5.7 years, a focal abnormality in the liver was found in 20 patients (13%). Of these, 15 patients (9%) were diagnosed as having hepatic metastasis. The number of the metastatic lesions with a short T1 and short T2 pattern were one (n = 1, 9%), two (n = 2, 18%), three (n = 1, 9%) and multiple (n = 7, 63%). The focal abnormalities of MR examinations in five other patients consisted of vascular artifacts (n = 3, 15%) and cysts with hemorrhage (n = 2, 10%).

CONCLUSIONS

The screening of MR examinations detected hepatic metastasis in 15 of 159 patients (9%) with locally controlled choroidal melanoma.

Recent malignant dyspnea

A 61-year-old man, consulted the clinic for dyspnea and cough worsening for 15 days. His past medical history was limited to a cutaneous melanoma 15 years previously, treated by surgery. He was thought to be cured, and was relapse free for the subsequent five years. Echocardiography revealed a large intracardiac mass occupying at least three quarters of the right ventricle, extending to the outflow tract. Echocardiography, MRI findings and anatomopathological examination are presented. Melanoma metastasis is discussed, with particular attention to cardiac localizations.

T1 hyperintense vertebral column melanoma metastases

We report a case of T1 hyperintense vertebral column metastatic disease in a 24-year-old man with metastatic melanoma. Radiologic work-up revealed multiple lytic vertebral metastases on CT with corresponding T1 hyperintensity on MR imaging. Whereas T1 hyperintensity associated with melanoma has been well documented, to our knowledge, this is the first described case of widespread T1 hyperintense metastatic bone disease. T1 hyperintense bone lesions are virtually always benign. However, correlation with the lesion appearances on other MR imaging sequences and imaging modalities as well as with the clinical history may occasionally suggest otherwise.

Multiple Sclerosis: Hyperintense Lesions in the Brain on Nonenhanced T1-weighted MR Images Evidenced as Areas of T1 Shortening

PURPOSE

To retrospectively document hyperintense lesions on nonenhanced T1-weighted magnetic resonance (MR) images in patients with multiple sclerosis (MS) and study their relationship to physical disability, disease course, and other MR markers of tissue damage (brain atrophy).

MATERIALS AND METHODS

Institutional review board approval was obtained; informed consent was waived for this HIPAA-compliant study, with 145 patients with MS (mean age, 43 years). Patients had relapsing-remitting (RR) (n=92) or secondary-progressive (SP) (n=49) MS; clinical course was unknown in four. Mean Expanded Disability Status Scale (EDSS) score was 3.5. T1 lesions were compared with normal white matter on nonenhanced images and judged hyperintense. Spearman rank correlation, Wilcoxon rank sum, and Fisher exact probability tests and analysis of variance and analysis of covariance (ANCOVA) were employed.

RESULTS

At least one T1 hyperintense lesion was found in 113 patients (total, 340 lesions). Two-thirds of lesions had hyperintense rim; others were uniformly hyperintense. Lesions were more common in patients with SP MS (P=.003, Wilcoxon test) and correlated with EDSS score (Spearman rho=0.19, P=.04) and brain atrophy measures (total cortical atrophy, Spearman rho=0.42, P<.001; third ventricular width, Spearman rho=0.40, P<.001) but not disease duration (Spearman rho=0.038, P=.69). Lesions were more likely multiple in the SP versus RR group (P<.001, Fisher test). After adjustment for disease course, T1 hyperintense lesions remained associated with brain atrophy (P<or=.001, ANCOVA). No independent effect of imager type (ANCOVA F value=1.4, P=.24) or spin-echo method (P=.67, Wilcoxon test) on number of lesions was detected. An effect of other MR protocol adjustments (analysis of variance F value=5.6, P=.001) was unconfirmed after clinical characteristic adjustment (ANCOVA F value=1.1, P=.35).

CONCLUSION

Hyperintense MS plaques on T1-weighted MR images are common and associated with brain atrophy, disability, and advancing disease; a hyperintense lesion may be a clinically relevant biomarker.

Superficial soft-tissue masses of the extremities

Superficial soft-tissue masses are among the most common indications for imaging of the extremities. A broad array of benign and malignant processes may be manifested in palpable cutaneous or subcutaneous masses or nodules. Most such lesions are treated with surgical excision, but some may be conservatively managed. The lesions can be differentiated according to their location in one or more skin layers (epidermis, dermis, and subcutis), their histologic composition, and the associated anatomic abnormality or disease process. Because the imaging characteristics of many benign soft-tissue lesions overlap with those of malignant ones, knowledge of the patient's clinical history (including any laboratory test results) and direct visual examination of the lesion often are important for differentiation. Histologic analysis may be necessary to achieve a definitive diagnosis.

Cardiac Magnetic Resonance Appearance of Myocarditis Caused by High Dose IL-2: Similarities to Community-Acquired Myocarditis

The purpose of this study was to describe and compare the cardiac magnetic resonance (CMR) characteristics of myocarditis caused by high dose interleukin-2 (7 patients) with community-acquired myocarditis (14 patients). A total of 21 patients with suspected myocarditis and elevated cardiac enzymes underwent cine CMR followed by delayed enhancement. The mean ejection fraction was mildly decreased in both groups. The location, pattern, and extent of DE were similar in both groups of patients. The CMR similarities between these two populations suggest that cytokine-mediated cytotoxicity may play an important role in community-acquired myocarditis.

Choroidal amelanotic melanoma in a patient with oculocutaneous albinism

CASE REPORT

We describe the clinical presentation of a choroidal amelanotic melanoma in a 46-year-old woman with oculocutaneous albinism. Clinical aspects, investigations, and management are presented, and findings from computed tomography and magnetic resonance imaging are described. Microscopic findings and histopathological features, demonstrating a spindle B-cell melanoma of the choroid, are also reviewed.

COMMENTS

Magnetic resonance imaging may be helpful in diagnosing amelanotic melanoma in patients with oculocutaneous albinism.

Imaging studies in patients with malignant melanoma in the female genital tract

The purpose of this study was to review magnetic resonance imaging (MRI) and pathologic features of primary malignant melanoma (melanoma) in the female genital tract. We retrospectively evaluated MRI in six women with melanoma of the genital tract. The signal intensity of the tumor on T1-weighted images (WI) was compared with the amount of melanin granules in hematoxylin-eosin stained sections of resected specimen. On T1WI, four melanomas showed a high signal intensity, one intermediate, and one low. The four melanomas with a high signal intensity on T1W1 were rich in melanin granules, while the one intermediate tumor had few granules. The other one was amelanotic. We believe that a high signal on T1WI is characteristic of primary melanotic melanoma of the female genital tract. Our findings suggest that it is strongly influenced by the presence of melanin granules.

MRI and malignant melanoma of the parotid gland

A case is presented highlighting the unusual features and the value of MRI in the assessment of metastatic malignant melanoma of the parotid gland.

Pancreatic head melanoma producing obstructive jaundice: magnetic resonance characteristics aiding differentiation from adenocarcinoma

A case is reported of malignant melanoma presenting as a mass in the head of the pancreas producing obstructive jaundice. On MR imaging the mass displayed signal characteristics not typical of adenocarcinoma but instead exhibited a low signal on T2-weighted images and early phase dynamic enhancement, the combination of which should suggest the possibility of melanoma.

Uveal melanoma: correlation of histopathologic and radiologic findings by using thin-section MR imaging with a surface coil

PURPOSE

To evaluate whether the different signal intensities at magnetic resonance (MR) imaging of melanoma are associated with a higher content of melanin.

MATERIALS AND METHODS

In a prospective study, MR imaging and ophthalmoscopic examination findings in 42 patients (19 women, 23 men; age range, 30-87 years) with uveal melanoma were compared with histopathologic examination findings obtained after enucleation. MR imaging was performed with 2-mm sections by using a 5-cm surface coil. T1- and T2-weighted images were obtained before and after contrast material administration.

RESULTS

In 33 (79%) of the patients, there was homogeneous tumor pigmentation, whereas in nine (21%) patients, there was inhomogeneous bipartite tumor pigmentation. Compared with the histopathologic data, the results of qualitative evaluation were accurate in 29 (58%) of 50 and in 26 (53%) of 49 tumorous areas on T1- and T2-weighted images, respectively. Quantitative evaluation yielded better results, especially at T1-weighted imaging; an 86% correlation was found. Because of methodological reasons, only the superficial pigmentation of inhomogeneous tumors could be evaluated with ophthalmoscopy.

CONCLUSION

Thin-section MR imaging of the eye enables an accurate prediction of melanomatous pigmentation with quantitative evaluation of plain T1-weighted images and is superior to ophthalmoscopy in cases of inhomogeneous pigmentation.