- Email: [email protected]
Interleukin-6 and cardiac myxoma
pericardial efision, right ventricular collapse, akinesia of the inferior wall, and a granular mass in the pericardial space consistent with intrapericardial clot (Figure 3C). Presence of clot was confirmed at surgery. One patient was hypotensive after coronary artery bypass surgery, and TTE showed only a pericardial effusion. TEE showed an ej%sion and pericardial clot lateral to the right atrium and anterior to the right ventricle. Surgical exploration revealed fresh blood and clot, and the patient improved after evacuation of the clot. Thirteen patients with documented systemic malignancies and pericardial metastases were studied. TTE detected pericardial masses in 5 patients. TEE documented pericardial masses consistent with metastatic disease in all patients; 12 patients had discrete masses within the pericardial space {Figure 4) and one had diffuse thickening of the pericardium. Pathologic conjirmation of malignancy was seen in 4 patients, and pericardial fluid cytology was positive in 2 others. Ten patients had pericardial efision, without masses or clot on TEE. TTE detected 7 of 10 e@sions. Intrapericardial strands were detected by TEE in 2 patients, and in none by TTE. TTE and TEE were equally sensitive in detecting moderate and large pericardial effusion. Three patients had technically inadequate TTE examinations: 2 had pericardial effusion on TEE and 1 had a large mass surrounding the superior vena cava. Surgical exploration confirmed the mass. One patient had an unusual radiographic cardiac silhouette. The TTE was normal. TEE revealed a cystic structure anterior to the left ventricle (Figure 5).
Although ‘ITE is the procedure of choice to evaluate a pericardial effusion,1,2 and may be used to evaluate pericardial masses such as metastases,1-5 TIE has shortcomings in the evaluation of other forms of pericardial disease.6,7 TTE is ~35% sensitive for diverse pericardial abnormalities, such as thickening.6 Also, TTE is less sensitive than TEE for detecting posterior pericardial hematoma and tamponade in patients after cardiac surgery8 Documentation of pericardial thickening in the presence of elevated and “equalized” diastolic filling pressures is clinically important, because it lends credence
Interleukin-6
to the diagnosis of constrictive pericarditis. In this study, horizontal plane TEE imaged pericardial thickening well enough to obtain measurements of all 13 patients, over approximately one half the circumference of the heart (Figure 2B). Interestingly, on similar apical 4-chamber ‘ITE, pericardial thickening was not apparent, possibly because of image degradation from near-field chest wall interference. Improved detection of intrapericardial clot by TEE versus TTE may be of considerable clinical importance because needle aspiration of intrapericardial clot in cardiac tamponade is usually not feasible, thus necessitating surgical evacuation. The inability to diagnose intrapericardial clot by TIE may be due to the echogenic nature of thrombus and the absence of characteristic echolucent space. Alternatively, inadequate gain may depict an echolucent space in the pericardial sac, and clot may not be detected. Among these 42 patients, TEE was superior to TTE in detecting pericardial thickening (11 of 13 vs 5 of 13), intrapericardial metastases (13 of 13 vs 3 of 13), intrapericardial clot (5 of 5 vs 0 of 5), and pericardial cysts (1 of 1 vs 0 of l), respectively. TEE added little to TTE in detecting pericardial effusions. The unavoidable bias in the interpretation due to the awareness of the clinical history before the echocardiograms is a limitation of the study. 1. Hoit BD. Imaging the pericardium. In: Shabetai R, ed. Diseases of the Peticardium: Cardiology Clinics. Philadelphia: WB Saunders, 1990~587~00. 2. Horowitz MS. Schultz CS. St&on EB. Sensitivitv. stxcificitv of echocardiographic diagnosis of pericard&l effusion. Circulation “l$j4;50:23$-247. 3. Gill PS, Chandrarama PAN, Meyer PR, Levine AM. Malignant lymphoma: cardiac involvement at initial presentation. J C/in Oncol 1987:5:216-224. 4. Chandraratna PAN, Aronow WAS. Detection of peticardial metastases by crosssectional echocardiography. Circuktion 1981;62;197-199. 5. Chandraratna PAN. Echocardiography and Doppler ultrasound in the evaluation of pericardial disease. Circularion 1991;84(suppl 1):1-303-I-3 10. 6. Hinds SW, Reisner SA, Amica AF, Meltzer RS. Diagnosis of pericardial abnormalities by 2D echo: a pathology-echocardiography correlation in 85 patients. Am HearrJ 1992;123:143-150. 7. Pandian NG, Skorton DJ, Kieso RA, Kerber RE. Diagnosis of constriction by two dimensional echocardiography: studies in a new, experimental animal model and in patients. J Am Coil Cardiol 1984;4:1164-I 173. 8. Kochar G, Jacobs LE, Kotler MNI. Right ahial compression in post-operative cardiac patients: detection by transesophageal echocardiography. J Am Co/l Cardrol 1990:16:511-516.
and Cardiac Myxoma
Tsugiyasu Kanda, MD, Shigeru Umeyama, MD, Atsushi Sasaki, MD, Yoichi Nakazato, MD, Yasuo Morishita, MD, Susumu Imai, MD, Tadashi Suzuki, MD, and Kazuhiko Murata, MD ardiac myxomas, the most common neoplasm of the C heart, are considered histologically benign. In patients with cardiac myxomas, various types of autoanti-
investigated the immunologic features and the immunohistochemistry of cardiac myxoma compared with other markers of myxoma.
bodies are produced and patients develop autoimmune symptoms. Cardiac myxoma cells produce interleukin-6 @L-6), messenger ribonucleic acid, and proteins.’ We
Between 1978 and 1993 at the Gunma Prefectural Cardiovascular Center and the Gunma University Hospital, we surgically treated 15 patients with cardiac myxoma (8 men and 7 women, mean age 58 years, range 39 to 76) (Table I). We reviewed their medical records, results of diagnostic tests, and studied their tumor specimens histologically. Patients were classijed as having an immunologic abnormality if they exhibited the following findings: fever >37”C at least once a day, weight
From the Second Department of Internal Medicine, First Department of Pathology, Second Department of Surgery, Gunma University School of Medicine, College of Medical Care and Technology, Gunma University, 3-39-15 Showa-machi, Maebashi 371, Japan. Manuscript received April 21, 1994; revised manuscript received May 27, 1994, and accepted May 31, 1994.
BRIEF REPORTS 965
TABLE
I Clinical
Features
Case No.
Age (yr) & Sex
1
2 3 4 5 6 7 8 9 10 11 12 13
52 M 68 F 47 M 55 F 76 F 43M 59 F 66 M 66 M 54 M 45 F 70 M 65 F
25 13 50 70 25 35 65 21 45 14 7 70
14
69 M
15
39 F
ESR (mm/hour)
CRP = C-reactive tricle; 0 = negative;
TABLE
II
and Immunologic Gamma Globulin (%)
CRP +
+: 0 0 +
16.5 17.1 16.1 22.4 14.3 15.2 19.9 20.5 20.2 20.4 17.9 21.8
57
++
21 .o
23
+
-
+: + 0 ++ +:
Abnormalities
lmmunoglobulin 0-W-V
413 (lg A) 1,918 (lg G) 636 (lg M) 416 (lg A) 2,251 (lg G) 457 (Ig A) -
of lmmunohistochemical
60 x 55 36 x 25 30 x 25 78 x 49 60 x 60 110x50x40 65 x 50 70 x 50 52 x 32 60 x 50 42 x 34 7x6x6 55 x 40
LA
50 x 40 x 39
LA
29 x 24 x 24
rate; lg = immunoglobin;
x x x x x
30 23 20 40 40
x x x x x
35 30 20 40 33
x 35
Surface Round, smooth Papillary Papillary Round, smooth Round, smooth Papillary Round, smooth Papillary Papillary Round, smooth Papillary Round, smooth Papillary
Papillary Papillary
LA = left atrium:
LV = left ven-
Staining
Case No. 1
0 1 0 000001 0 000001 0 0 2 2 2 2 1 2 1
0 0 0
1 0 0
0 0 0
:o
ND
0
1
0
0
0
0
1
0 0 0 0 0 0 0 0 0
2 0 0
0 0 0
0 0 0
0 1 ND
1
0
0
1
00000010
0 0 0 1 0
0 0 0 0 0
0 2 2 0 0
1 1 0 0 0
00000010 20000010 20100020 00000010 00000010
8
0
3
0
2
8
5
(53)
(0)
(20)
(0)
(13)
(62)
(33)
Number positive P4
Myxoma Size (mm x mm x mm)
LA LA LA LA LA LA LA LA LA LA LA LV LA
- Desmin TETETE
2 3 4 5 6 7 8 9 10 11 12 13 14 15
Vimentin -
Lesion Site
-
protein; ESR = erythrocyte sedimentation + = weak positive; ++ = strong positive.
Results
in 15 Patients
- F VIII
- s-100 TETETETE
- NSE
0 0 00000000 00000000 00000010 20000010 0 0 10000020 00000011 2 0
0
E = endothelium; F VIII = factor VIII-related antigen; IL-6 = interleukin-6; enolase; S-100 = S-100 protein; T = tumor cells: 0 = negative: 1 = weak
Cytokeratin
0
01
0
IL-6
0
2
0
1020
0
0
0
1
0
1
0
1
1
1
1
12
2
(0)
(7)
(7)
(7)
(7)
(80)
(13)
ND = not detected; NSE = neuron-specific positive; 2 = strong positive.
loss >3 kg in 3 months, an abnormally prolonged sedimentation rate >25 mmlhour, an increased serum level of C-reactive protein, a serum level of gamma globulin >20%, the presence of an abnormal immunoglobulin, a hemoglobin level ~12 gldl, rheumatoidfactors, and antinuclear antibodies.2 Tumor specimens were fixed in 4% buffered formaldehyde (pH 7.2) and embedded in para&. Sections 5 pm thick were used for conventional light microscopy and immunohistochemistry. For light microscopy, the slides were stained with hematoqlin and eosin and Mallory stains. The ABC method was used for immunohistochemical investigation.3 The mouse monoclonal antibody against human IL-6, a gift of Dr. Tadashi Matsuda of Osaka University Medical Research Center, was
applied. Other monoclonal antibodies used to detect antigens were: desmin, vimentin, and factor VIII-related antigen (all from Dako, Copenhagen, Denmark) as mesenchymal markers; cytokeratin (Becton Dickinson & Co., Lombard, Illinois) as an epithelial marker; and S100 protein4 and neuron specific enolase (Immunon Co., Ltd., Urica, Michigan) as neuroendocrine markers. The staining reactions of the antibodies were scored 0, I, or 2 for negative, low, and high intensity, respectively. Statistical analysis was per$ormed with the chisquare test with Yate’s correction. A p value co.05 was considered statistically significant. Myxoma was present in the left atrium in 14 patients and in the left ventricle in 1 patient (Table I). Tumor size ranged from 7 X 6 X 6 mm to II0 X 50 X 40 mm.
966
NOVEMBER 1, 1994
THE
AMERICAN JOURNAL OF CARDIOLOGY@ VOLUME 74
Macroscopically, the lesions were pedunculate and papillary in 9 patients, and smooth and round in 6 patients. Light microscopic examination showed the typical features of cardiac myxoma in all 15 patients. There was a myxomatous stroma with vascular channels and scattered immune cells such as macrophages, neutrophils, and lymphocytes. Tumor cells were embedded in the stroma and were mostly polygonal, hut some were spindleshaped. Twelve of the 15 tumors (80%) reacted with anti-ll6 antibody (Table II). The intensity was low in 8 and high in 4 tumors. The endothelial cells in 2 (13%) were also positive for that antibody. The tumor cells that positively stained with anti-IL-6 antibody were scattered in the stroma, particularly in the outer layer of the so-called “double-wall appearance” (Figure 1). Desmin, 1 of the mesenchymal markers, stained in 8 of 15 tumors (53%). Other mesenchymal markers, such as vimentin and factor VIII-related antigen were present in 3 (20%) or 2 (13%) of 1.5 tumors, respectively. Neuroendocrine markers, such as S-100 protein and neuron-specific enolase, stained in only 5 tumors (33%) and 1 tumor (7%), respectively. Staining for cytokeratin as a marker of epithelium was positive in only 1 of 15 tumors (7%). The endothelial cells in tumors were stained by factor VIIIrelated antigen, as previously described.5 Ten of the 13 myxoma patients (77%) with immunologic symptoms had tumors positive for IL-6. Three patients with myxoma that stained negatively by anti-ll6 antibody had immunologic findings, and another 2 without immunologic features had myxomas positive for IL-6. The immunoreactivity of the myxomas against IL6 was not significantly associated with the immunologic findings.
Of 15 patients with cardiac myxomas, 13 (87%) had immunologic symptoms. IL-6 expression was present in 12 of 15 tumors (80%). The incidence of positivity for IL-6 expression exceeded that of other markers, such as mesenchymal, neuroendocrine, and epithelial antigens, previously regarded as markers of myxoma.6 In our study, 13 of 15 patients (87%) had such immunologic abnormalities. Ten of 12 patients (83%) with IL-6-positive myxoma had immunologic abnormalities. The identity and histogenesis of cardiac myxoma is controversial. In an immunocytochemical study, myxoma cells reacted positively with mesenchymal markers, such as vimentin and desmin.7 In ultrastructural studies, myxoma cells showed an abundance of fine cytoplasmic fibrils similar to those in vascular smooth muscle cells, with many similarities to embryonic endothelial cells.7s These studies support the concept of “vasoformative reserve cells,” which may differentiate into endothelial cells, smooth muscle cells, and fibroblasts.9 Tissue culture of cardiac myxomas also yields cells of this nature.‘O IL-6 is synthesized by endothelial cells and fibroblasts.““* Although other mesenchymal markers, such as desmin, vimentin, and factor VIII-related antigen had lower rates of positivity in tumor cells compared with IL-6, this finding is consistent with the concept of vasoformative reserve cells.
AGURE 1. Positive reaction of cardiac myxoma cells with anti-interleukiti antibody. The outer layer (wide arrow) having a double-wall appearance is prominent, but the inner layer (narrow arrow) is negative. (Original magnification X 400, reduced by 490/o.)
We conclude that IL-6 should be considered a marker of myxoma. The frequent immunologic abnormalities in patients with cardiac myxoma may be related to the IL-6 secreted from the myxoma itself. Admowletlgments: We are grateful to Tetsuo Iijima, MD, Shigeru Ohshima, MD, Kazuo Yuasa, MD, Toshio Konishi, MD, and Koichi Taniguchi, MD, for their cooperation in this study, and Yoshiko Nor&a for her excellent technical assistance. 1. Hirano T, Taga T, Yasukawa K, Nakajima K, N&no N, Takatsuki F, Shimtzu M, Murashima A. Tsunasawa S, Sakiyama F, Kishimoto T. Human B-cell differentiation factor defined by an anti-peptide antibody and its possible role in autozutibody production. Proc Nor/ Acud Sci USA 19X7$4:228-231. 2. Seguin JR, Beigbeder J-Y, Hvass U, Langlois I, Grolleau R, Jourdan M, Klein B, Bataille R, Chaptal P-A. Interleukin-6 production by cardiac myxomas may explain constitutional symptoms. J Thorac Cardiovasc Surg 1992; 103:599-600. 3. Hsu S. Raine L, Fanger H. Use of avidin-biotin-peroxidase complex (ABC) in immunoperoxidase techniques: a comparison between ABC and unlabeled antibody (PAP) procedures. J Histochem Cytochcm 198 1:29:577-580. 4. Yamaguchi H. Studies on the immunohistochemical localization of S-100 and glial fibrillary acidic proteins in the rat nervous system and in human brain tumors. Bruin Nerve 1980;32:10.55-1064. 5. Tanimura A, Kitazono M, Nagayama K, Tanaka S, Kosuga K. Cardiac myxoma: morphologic, histochemical, and tissue culture studies. Num Par/m/ 1988: 19:31&322. 5. Kishimoto T, Akira S, Taga T. Interleukin-6 and its receptor: a paradigm for cytokines. S&nrr 1992:258:593-597. 7. Curschellas E, Toia D, Bomer M, Mihatsch MJ. Gudat F. Cardiac myxotnas: immunohistochemical study of benign and malignant variants. VIW~OM~S Arch A 1991:418:485-491. 8. Markwald RR, Fitzhams TP, Manasek FJ. Structural development of endocardial cushions. Am J Anut 1977;148:85-120. 9. Stein AA, Mauro J, Thibodeau L, Alley R. The histogenesis of cardiac myxoma: relation to other proliferative diseases of sub-endothelial vasoformative reserve cells. Parho/ Annu 1969;4:293-312. 10. McAllister HA Jr, Feroglio JJ Jr. Tumors of the Cardiovascular System. Atlas of Tumor Pathology. Fast 15. 2nd wies. Washington, DC: Armed Forces Institute of Pathology, 1978. 11. Notioka K, Ham M, Htigai M, Kitami A, Hirose T, Suzuki K. Kawakami M. Tabata H, Kawagoe M, Nakamura H. Production of B cell stimulatory factw2/inter&kin-6 activity by human endothelial cells. Biochem Biop,phys Res Commun 198X; 153:104-1051. 12. Suematsu S, Matsuda T, Aozawa K, Akira S, Nakano N, Ohno S, Miyazaki .I, Yamamura K, Hirano T, Kishimoto T. lgG1 plastnacytosis in interleukin-6 transgenie mice. Pr~x Nat/ Acud Sci USA 1989;86:7547-7552.
BRIEF REPORTS
967
Although ‘ITE is the procedure of choice to evaluate a pericardial effusion,1,2 and may be used to evaluate pericardial masses such as metastases,1-5 TIE has shortcomings in the evaluation of other forms of pericardial disease.6,7 TTE is ~35% sensitive for diverse pericardial abnormalities, such as thickening.6 Also, TTE is less sensitive than TEE for detecting posterior pericardial hematoma and tamponade in patients after cardiac surgery8 Documentation of pericardial thickening in the presence of elevated and “equalized” diastolic filling pressures is clinically important, because it lends credence
Interleukin-6
to the diagnosis of constrictive pericarditis. In this study, horizontal plane TEE imaged pericardial thickening well enough to obtain measurements of all 13 patients, over approximately one half the circumference of the heart (Figure 2B). Interestingly, on similar apical 4-chamber ‘ITE, pericardial thickening was not apparent, possibly because of image degradation from near-field chest wall interference. Improved detection of intrapericardial clot by TEE versus TTE may be of considerable clinical importance because needle aspiration of intrapericardial clot in cardiac tamponade is usually not feasible, thus necessitating surgical evacuation. The inability to diagnose intrapericardial clot by TIE may be due to the echogenic nature of thrombus and the absence of characteristic echolucent space. Alternatively, inadequate gain may depict an echolucent space in the pericardial sac, and clot may not be detected. Among these 42 patients, TEE was superior to TTE in detecting pericardial thickening (11 of 13 vs 5 of 13), intrapericardial metastases (13 of 13 vs 3 of 13), intrapericardial clot (5 of 5 vs 0 of 5), and pericardial cysts (1 of 1 vs 0 of l), respectively. TEE added little to TTE in detecting pericardial effusions. The unavoidable bias in the interpretation due to the awareness of the clinical history before the echocardiograms is a limitation of the study. 1. Hoit BD. Imaging the pericardium. In: Shabetai R, ed. Diseases of the Peticardium: Cardiology Clinics. Philadelphia: WB Saunders, 1990~587~00. 2. Horowitz MS. Schultz CS. St&on EB. Sensitivitv. stxcificitv of echocardiographic diagnosis of pericard&l effusion. Circulation “l$j4;50:23$-247. 3. Gill PS, Chandrarama PAN, Meyer PR, Levine AM. Malignant lymphoma: cardiac involvement at initial presentation. J C/in Oncol 1987:5:216-224. 4. Chandraratna PAN, Aronow WAS. Detection of peticardial metastases by crosssectional echocardiography. Circuktion 1981;62;197-199. 5. Chandraratna PAN. Echocardiography and Doppler ultrasound in the evaluation of pericardial disease. Circularion 1991;84(suppl 1):1-303-I-3 10. 6. Hinds SW, Reisner SA, Amica AF, Meltzer RS. Diagnosis of pericardial abnormalities by 2D echo: a pathology-echocardiography correlation in 85 patients. Am HearrJ 1992;123:143-150. 7. Pandian NG, Skorton DJ, Kieso RA, Kerber RE. Diagnosis of constriction by two dimensional echocardiography: studies in a new, experimental animal model and in patients. J Am Coil Cardiol 1984;4:1164-I 173. 8. Kochar G, Jacobs LE, Kotler MNI. Right ahial compression in post-operative cardiac patients: detection by transesophageal echocardiography. J Am Co/l Cardrol 1990:16:511-516.
and Cardiac Myxoma
Tsugiyasu Kanda, MD, Shigeru Umeyama, MD, Atsushi Sasaki, MD, Yoichi Nakazato, MD, Yasuo Morishita, MD, Susumu Imai, MD, Tadashi Suzuki, MD, and Kazuhiko Murata, MD ardiac myxomas, the most common neoplasm of the C heart, are considered histologically benign. In patients with cardiac myxomas, various types of autoanti-
investigated the immunologic features and the immunohistochemistry of cardiac myxoma compared with other markers of myxoma.
bodies are produced and patients develop autoimmune symptoms. Cardiac myxoma cells produce interleukin-6 @L-6), messenger ribonucleic acid, and proteins.’ We
Between 1978 and 1993 at the Gunma Prefectural Cardiovascular Center and the Gunma University Hospital, we surgically treated 15 patients with cardiac myxoma (8 men and 7 women, mean age 58 years, range 39 to 76) (Table I). We reviewed their medical records, results of diagnostic tests, and studied their tumor specimens histologically. Patients were classijed as having an immunologic abnormality if they exhibited the following findings: fever >37”C at least once a day, weight
From the Second Department of Internal Medicine, First Department of Pathology, Second Department of Surgery, Gunma University School of Medicine, College of Medical Care and Technology, Gunma University, 3-39-15 Showa-machi, Maebashi 371, Japan. Manuscript received April 21, 1994; revised manuscript received May 27, 1994, and accepted May 31, 1994.
BRIEF REPORTS 965
TABLE
I Clinical
Features
Case No.
Age (yr) & Sex
1
2 3 4 5 6 7 8 9 10 11 12 13
52 M 68 F 47 M 55 F 76 F 43M 59 F 66 M 66 M 54 M 45 F 70 M 65 F
25 13 50 70 25 35 65 21 45 14 7 70
14
69 M
15
39 F
ESR (mm/hour)
CRP = C-reactive tricle; 0 = negative;
TABLE
II
and Immunologic Gamma Globulin (%)
CRP +
+: 0 0 +
16.5 17.1 16.1 22.4 14.3 15.2 19.9 20.5 20.2 20.4 17.9 21.8
57
++
21 .o
23
+
-
+: + 0 ++ +:
Abnormalities
lmmunoglobulin 0-W-V
413 (lg A) 1,918 (lg G) 636 (lg M) 416 (lg A) 2,251 (lg G) 457 (Ig A) -
of lmmunohistochemical
60 x 55 36 x 25 30 x 25 78 x 49 60 x 60 110x50x40 65 x 50 70 x 50 52 x 32 60 x 50 42 x 34 7x6x6 55 x 40
LA
50 x 40 x 39
LA
29 x 24 x 24
rate; lg = immunoglobin;
x x x x x
30 23 20 40 40
x x x x x
35 30 20 40 33
x 35
Surface Round, smooth Papillary Papillary Round, smooth Round, smooth Papillary Round, smooth Papillary Papillary Round, smooth Papillary Round, smooth Papillary
Papillary Papillary
LA = left atrium:
LV = left ven-
Staining
Case No. 1
0 1 0 000001 0 000001 0 0 2 2 2 2 1 2 1
0 0 0
1 0 0
0 0 0
:o
ND
0
1
0
0
0
0
1
0 0 0 0 0 0 0 0 0
2 0 0
0 0 0
0 0 0
0 1 ND
1
0
0
1
00000010
0 0 0 1 0
0 0 0 0 0
0 2 2 0 0
1 1 0 0 0
00000010 20000010 20100020 00000010 00000010
8
0
3
0
2
8
5
(53)
(0)
(20)
(0)
(13)
(62)
(33)
Number positive P4
Myxoma Size (mm x mm x mm)
LA LA LA LA LA LA LA LA LA LA LA LV LA
- Desmin TETETE
2 3 4 5 6 7 8 9 10 11 12 13 14 15
Vimentin -
Lesion Site
-
protein; ESR = erythrocyte sedimentation + = weak positive; ++ = strong positive.
Results
in 15 Patients
- F VIII
- s-100 TETETETE
- NSE
0 0 00000000 00000000 00000010 20000010 0 0 10000020 00000011 2 0
0
E = endothelium; F VIII = factor VIII-related antigen; IL-6 = interleukin-6; enolase; S-100 = S-100 protein; T = tumor cells: 0 = negative: 1 = weak
Cytokeratin
0
01
0
IL-6
0
2
0
1020
0
0
0
1
0
1
0
1
1
1
1
12
2
(0)
(7)
(7)
(7)
(7)
(80)
(13)
ND = not detected; NSE = neuron-specific positive; 2 = strong positive.
loss >3 kg in 3 months, an abnormally prolonged sedimentation rate >25 mmlhour, an increased serum level of C-reactive protein, a serum level of gamma globulin >20%, the presence of an abnormal immunoglobulin, a hemoglobin level ~12 gldl, rheumatoidfactors, and antinuclear antibodies.2 Tumor specimens were fixed in 4% buffered formaldehyde (pH 7.2) and embedded in para&. Sections 5 pm thick were used for conventional light microscopy and immunohistochemistry. For light microscopy, the slides were stained with hematoqlin and eosin and Mallory stains. The ABC method was used for immunohistochemical investigation.3 The mouse monoclonal antibody against human IL-6, a gift of Dr. Tadashi Matsuda of Osaka University Medical Research Center, was
applied. Other monoclonal antibodies used to detect antigens were: desmin, vimentin, and factor VIII-related antigen (all from Dako, Copenhagen, Denmark) as mesenchymal markers; cytokeratin (Becton Dickinson & Co., Lombard, Illinois) as an epithelial marker; and S100 protein4 and neuron specific enolase (Immunon Co., Ltd., Urica, Michigan) as neuroendocrine markers. The staining reactions of the antibodies were scored 0, I, or 2 for negative, low, and high intensity, respectively. Statistical analysis was per$ormed with the chisquare test with Yate’s correction. A p value co.05 was considered statistically significant. Myxoma was present in the left atrium in 14 patients and in the left ventricle in 1 patient (Table I). Tumor size ranged from 7 X 6 X 6 mm to II0 X 50 X 40 mm.
966
NOVEMBER 1, 1994
THE
AMERICAN JOURNAL OF CARDIOLOGY@ VOLUME 74
Macroscopically, the lesions were pedunculate and papillary in 9 patients, and smooth and round in 6 patients. Light microscopic examination showed the typical features of cardiac myxoma in all 15 patients. There was a myxomatous stroma with vascular channels and scattered immune cells such as macrophages, neutrophils, and lymphocytes. Tumor cells were embedded in the stroma and were mostly polygonal, hut some were spindleshaped. Twelve of the 15 tumors (80%) reacted with anti-ll6 antibody (Table II). The intensity was low in 8 and high in 4 tumors. The endothelial cells in 2 (13%) were also positive for that antibody. The tumor cells that positively stained with anti-IL-6 antibody were scattered in the stroma, particularly in the outer layer of the so-called “double-wall appearance” (Figure 1). Desmin, 1 of the mesenchymal markers, stained in 8 of 15 tumors (53%). Other mesenchymal markers, such as vimentin and factor VIII-related antigen were present in 3 (20%) or 2 (13%) of 1.5 tumors, respectively. Neuroendocrine markers, such as S-100 protein and neuron-specific enolase, stained in only 5 tumors (33%) and 1 tumor (7%), respectively. Staining for cytokeratin as a marker of epithelium was positive in only 1 of 15 tumors (7%). The endothelial cells in tumors were stained by factor VIIIrelated antigen, as previously described.5 Ten of the 13 myxoma patients (77%) with immunologic symptoms had tumors positive for IL-6. Three patients with myxoma that stained negatively by anti-ll6 antibody had immunologic findings, and another 2 without immunologic features had myxomas positive for IL-6. The immunoreactivity of the myxomas against IL6 was not significantly associated with the immunologic findings.
Of 15 patients with cardiac myxomas, 13 (87%) had immunologic symptoms. IL-6 expression was present in 12 of 15 tumors (80%). The incidence of positivity for IL-6 expression exceeded that of other markers, such as mesenchymal, neuroendocrine, and epithelial antigens, previously regarded as markers of myxoma.6 In our study, 13 of 15 patients (87%) had such immunologic abnormalities. Ten of 12 patients (83%) with IL-6-positive myxoma had immunologic abnormalities. The identity and histogenesis of cardiac myxoma is controversial. In an immunocytochemical study, myxoma cells reacted positively with mesenchymal markers, such as vimentin and desmin.7 In ultrastructural studies, myxoma cells showed an abundance of fine cytoplasmic fibrils similar to those in vascular smooth muscle cells, with many similarities to embryonic endothelial cells.7s These studies support the concept of “vasoformative reserve cells,” which may differentiate into endothelial cells, smooth muscle cells, and fibroblasts.9 Tissue culture of cardiac myxomas also yields cells of this nature.‘O IL-6 is synthesized by endothelial cells and fibroblasts.““* Although other mesenchymal markers, such as desmin, vimentin, and factor VIII-related antigen had lower rates of positivity in tumor cells compared with IL-6, this finding is consistent with the concept of vasoformative reserve cells.
AGURE 1. Positive reaction of cardiac myxoma cells with anti-interleukiti antibody. The outer layer (wide arrow) having a double-wall appearance is prominent, but the inner layer (narrow arrow) is negative. (Original magnification X 400, reduced by 490/o.)
We conclude that IL-6 should be considered a marker of myxoma. The frequent immunologic abnormalities in patients with cardiac myxoma may be related to the IL-6 secreted from the myxoma itself. Admowletlgments: We are grateful to Tetsuo Iijima, MD, Shigeru Ohshima, MD, Kazuo Yuasa, MD, Toshio Konishi, MD, and Koichi Taniguchi, MD, for their cooperation in this study, and Yoshiko Nor&a for her excellent technical assistance. 1. Hirano T, Taga T, Yasukawa K, Nakajima K, N&no N, Takatsuki F, Shimtzu M, Murashima A. Tsunasawa S, Sakiyama F, Kishimoto T. Human B-cell differentiation factor defined by an anti-peptide antibody and its possible role in autozutibody production. Proc Nor/ Acud Sci USA 19X7$4:228-231. 2. Seguin JR, Beigbeder J-Y, Hvass U, Langlois I, Grolleau R, Jourdan M, Klein B, Bataille R, Chaptal P-A. Interleukin-6 production by cardiac myxomas may explain constitutional symptoms. J Thorac Cardiovasc Surg 1992; 103:599-600. 3. Hsu S. Raine L, Fanger H. Use of avidin-biotin-peroxidase complex (ABC) in immunoperoxidase techniques: a comparison between ABC and unlabeled antibody (PAP) procedures. J Histochem Cytochcm 198 1:29:577-580. 4. Yamaguchi H. Studies on the immunohistochemical localization of S-100 and glial fibrillary acidic proteins in the rat nervous system and in human brain tumors. Bruin Nerve 1980;32:10.55-1064. 5. Tanimura A, Kitazono M, Nagayama K, Tanaka S, Kosuga K. Cardiac myxoma: morphologic, histochemical, and tissue culture studies. Num Par/m/ 1988: 19:31&322. 5. Kishimoto T, Akira S, Taga T. Interleukin-6 and its receptor: a paradigm for cytokines. S&nrr 1992:258:593-597. 7. Curschellas E, Toia D, Bomer M, Mihatsch MJ. Gudat F. Cardiac myxotnas: immunohistochemical study of benign and malignant variants. VIW~OM~S Arch A 1991:418:485-491. 8. Markwald RR, Fitzhams TP, Manasek FJ. Structural development of endocardial cushions. Am J Anut 1977;148:85-120. 9. Stein AA, Mauro J, Thibodeau L, Alley R. The histogenesis of cardiac myxoma: relation to other proliferative diseases of sub-endothelial vasoformative reserve cells. Parho/ Annu 1969;4:293-312. 10. McAllister HA Jr, Feroglio JJ Jr. Tumors of the Cardiovascular System. Atlas of Tumor Pathology. Fast 15. 2nd wies. Washington, DC: Armed Forces Institute of Pathology, 1978. 11. Notioka K, Ham M, Htigai M, Kitami A, Hirose T, Suzuki K. Kawakami M. Tabata H, Kawagoe M, Nakamura H. Production of B cell stimulatory factw2/inter&kin-6 activity by human endothelial cells. Biochem Biop,phys Res Commun 198X; 153:104-1051. 12. Suematsu S, Matsuda T, Aozawa K, Akira S, Nakano N, Ohno S, Miyazaki .I, Yamamura K, Hirano T, Kishimoto T. lgG1 plastnacytosis in interleukin-6 transgenie mice. Pr~x Nat/ Acud Sci USA 1989;86:7547-7552.
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