Number 10-26: Metastatic Malignant Melanoma Presenting as Incidental Cardiac Mass: CMR Diagnosis

Case from: Ketheswaram Caruppannan, Robert W.W. Biederman, Gregory Smith, Vikas K. Rathi.

Institute: Center for Cardiovascular MRI, Division of Cardiology, Allegheny General, Hospital, 320 E North Avenue, Pittsburgh, PA-15212, USA.

Clinical history: A 74-year old white male with history of coronary artery disease with previous CABG and chronic renal failure on hemodialysis, presented to our institution after a spontaneous fall while lawn mowing. He did not sustain head injury. He also had a history of colonic melanoma diagnosed on screening colonoscopy and had undergone resection 2 years ago.

 

 

Figure 1                                                                                                   Figure 2

 

 

The admission non-contrast head CT showed a large right temporal mass with hemorrhagic changes and severe vasogenic edema (Figure 1). His screening non-gated, contrast-enhanced CT of the chest and abdomen showed multiple peritoneal metastases, a small thoracic subcutaneous nodule and a right middle lobe mass (Figure 2).

 

 

Figure 3 

 

 

 

    

Movie 1                                                             Movie 2

 

A transthoracic echocardiogram (TTE) confirmed a large sessile mass (2.4 x 2.1cm) attached to the interatrial septum and posterior wall of the right atrium with independent mobility. These features appeared similar to that of an atrial myxoma (Movies 1 & 2).
Further tissue characterization of the mass was organized to rule out a second malignancy, before the patient could be considered for systemic chemotherapy and whole brain radiation, given the anatomical features of the multiple mass lesions. Bronchial washings were negative for malignant cells.
The patient underwent CMR to characterize the right atrial mass and to differentiate between myxoma, metastatic melanoma or thrombus, given the presence of an indwelling dialysis catheter in the superior vena cava.

 

 

Figure 4 

 

CMR Findings: Breath-hold T1 weighted images (Figure 4 - four-chamber view) show a well defined, hyperintense (similar signal characteristics to fat) right atrial mass, suggestive of short T1 relaxation, due to the presence of melanin or hemorrhage.

 

 

Figure 5 

 

 

Figure 6 

 

T2-weighted, triple inversion recovery images with fat saturation (Figures 5 & 6) show a hyperintense lesion, due to increased proton density, suggestive of a tumor.

 

      

Movie 3                                                                    Movie 4

 

Steady state free precession cine images (SSFP) show the isointense mobile mass lesion in the right atrium (Movies 3 & 4). No contrast was given due to renal failure and low GFR.

Based on the T1 and T2 weighted characteristics of this lesion (see Table 1), the mass is most likely a metastatic melanoma [1,2].

 

  

Table 1

 

 

Movie 5

 

Conclusion: The patient underwent and Intra Cardiac Echo (ICE) - guided biopsy of the lesion (Movie 5).

 

Figure 7 

 

The immuno-histochemical staining of the mass revealed diffuse positive staining for S-100 (Figure 7B), strong focal to diffuse staining for melan-A (Figure 7A), focal staining for HMB-45 (Figure 7C) and positive staining for MiTF (Figure 7D), all supportive of metastatic malignant melanoma.

Perspective: Metastatic melanoma has an unpredictable biological behavior and is the most common metastatic malignancy to the heart [3]. Due to hematogenous spread, the cardiac metastasis is most commonly intramyocardial and multifocal but there are reports of pericardial, valvular and endocardial involvement.
The degree of melanin in the tumor determines the T1 signal characteristics [4,5]. Most metastatic melanoma will be hyperintense on T1- weighted images due to high melanin content, which shortens the T1 relaxation time due to paramagnetic metal scavenging [6]. The T2-weighted images are hyperintense due to increased proton density or water content of the tumor.
CMR is complimentary to echocardiography and is an important and appropriate test to localize, characterize and distinguish the cardiac and paracardiac masses [7,8,9].

References:
1. Rathi VK, Williams RB, Yamrozik J, Grill H, Biederman RW. Cardiovascular magnetic resonance of the charcoal heart. J Cardiovasc Magn Reson. 2008 Jul 9;10:37.
2. Patrick J. Sparrow, John B. Kurian, Tim R. Jones, Mohan U.Sivananthan. MR Imaging of Cardiac Tumors. RadioGraphics 2005; 25:1255-1276.
3. Savoia P, Fierro MT, Zaccagna A, et al. Metastatic melanoma of the heart. J Surg Oncol 2000; 75: 203-207.
4. Premkumar A, Marincola F, Taubenberger J, Chow C, Venzon D, Schwartzentruber D: Metastatic melanoma: correlation of MRI characteristics and histopathology. J Magn Reson Imaging 1996, 6(1):190-4.
5. Rathi VK (2006). Cardiac and paracardiac masses. Textbook of Cardiovascular Magnetic Resonance. Pages 299-326. Informa healthcare. ISBN: 0-8247-5841-2.
6. Enochs WS, Petherick P, Bogdanova A, Mohr U, Weissleder R. Paramagnetic metal scavenging by melanin: MR imaging. Radiology 1997 Aug; 204(2):417- 23.
7. Maria I. Altbach, Scott W. Squire, Vijayasree Kudithipudi, Lisa Castellano, Vincent L. Sorrell. Cardiac MRI is Complementary to Echocardiography in the Assessmentof Cardiac Masses. Echocardiography, Vol. 24, No. 3, 2007.
8.Hendel RC et al. ACCF/ACR/SCCT/SCMR/ASNC/NASCI/SCAI/SIR 2006 appropriateness criteria for cardiac computed tomography and cardiac magnetic resonance imaging: J Am Coll Cardiol. 2006 Oct 3; 48(7):1475-97.
9. Pennell DJ, Sechtem UP, Higgins CB, et al. Clinical indications for cardiovascular magnetic resonance (CMR): Consensus Panel report. Eur Heart J 2004;25:1940-65.

COTW handling editor: Monica Deac 

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Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
[quote="drflett"]I have to say from the CMR pictures alone, melanoma would not have immediately sprung to mind so this is a good learning point for me ......quote]ChiaraThat was why I qualified it with the above - from...
On: 02/06/2011 By: drflett Read more?

Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
well done, nicely presented at the SCMR best case of the week sesion.interseting about melanin being a T1 shortening agentlink here to your charcoal heart http://www.jcmr-online.com/content/10/1/37 ...
On: 02/04/2011 By: moon Read more?

Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
Did not know that this case generated so much discussion. Ok...here are few thoughts of my own. 1. Although it was known from CT that there a right atrial mass most likely an melanoma metastasis but other etiologies...
On: 02/02/2011 By: vikasrathi Read more?

Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
Totally agree with you Andy. However, bear in mind that from the hx we knew he had a colonic melanoma for which he underwent resection. So I guess this is a big hint. ...
On: 01/27/2011 By: chiarabd Read more?

Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
I have to say from the CMR pictures alone, melanoma would not have immediately sprung to mind so this is a good learning point for me (having not seen melanoma in the heart before). I think my report would have...
On: 01/26/2011 By: drflett Read more?

Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
Would be interesting to get Vikas's opinion on this. He is the senior author for this case. Vikas- any thoughts? ...
On: 01/25/2011 By: chiarabd Read more?

Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
Great case, but as is often the case, one wonders whether CMR really changed the overall management or prognosis in this patient with metastatic disease... ...
On: 01/25/2011 By: gvorobiof Read more?

Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
The right atrial mass was initially an incidental finding on the non-gated contrast enhanced chest CT that the patient underwent for screening. Wasnt CT enough to tissue characterise this mass and differentiate between myxoma, metastatic melanoma or thrombus? Why...
On: 01/24/2011 By: chiarabd Read more?

Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
This is a very nice case on the role of CMR for non invasive tissue characterisation of a right atrial cardiac mass. This case was indeed one of the best 5 cases published this year. ...
On: 01/24/2011 By: chiarabd Read more?

Re: Number 10-26: Metastatic Malignant Melanoma Presenting a
This was our 100th case published! ...
On: 01/24/2011 By: chiarabd Read more?