CASE REPORT

Interleukin-6-producing Thymic Squamous CellCarcinoma Associated with Castleman's Disease

and Nephrotic SyndromeNorihiko Matsumura, Hideo Shiiki*, Naotoshi Saito, Hiroki Uramoto,

Masakazu Hanatani, Hideo Nonaka and Shinobu Nakamura**

Abstract

Whena 63-year-old man was hospitalized with nephrot-ic syndrome due to focal segmental glomerulosclerosis, amediastinal mass was discovered. A biopsy specimen ob-tained by mediastinoscopy showed findings compatible withthe plasma cell type of Castleman's disease. Fever, anemia,and anti-nuclear antibody were present. Serum concentra-tions of gammaglobulin, acute phase proteins, and, moststrikingly, interleukin-6 (IL-6) were elevated. Methylpred-nisolone pulse therapy resulted in no clinical improvement.Pathologic examination of the resected thymic tumorshowed a squamous cell carcinoma immunoreactive for IL-6. To our knowledge, this case represents the first reportedIL-6-producing thymic squamouscell carcinoma associatedwith Castleman's disease and nephrotic syndrome.(Internal Medicine 41: 871-874, 2002)

Key words: mediastinal tumor, focal segmental glomeruloscle-rosis

Introduction

Interleukin-6 (IL-6) is a multifunctional cytokine actingmainly in the initiation of acute inflammatory responses andinduction of B lymphocyte proliferation and differentiation ( 1 ).This cytokine is produced by a variety of cells such as T cells,B cells, monocytes, fibroblasts, keratinocytes, astrocytes, andmesangial cells (1, 2). Several human tumors or lymphopro-liferative lesions also secrete IL-6, including multiple myeloma(3), renal cell carcinoma (4), lung cancer (5), cervical cancer(6), esophageal cancer (7), and Castleman's disease (8). Fur-thermore, the serum IL-6 concentration is correlated with dis-ease status and prognosis in esophageal squamouscell carci-

noma (7).Thymic carcinoma is a rare mediastinal cancer. This tumordisplays notable cytologic atypia in the neoplastic epithelialcomponent of the thymus and is likely to invade adjoining tis-sue and metastasize (9). Amongthymic carcinomas, squamouscell carcinoma is the most commonand ordinarily is of rela-tively low grade histologically (10). Whether or not thymicsquamous cell carcinomas produce IL-6 has not been estab-lished. We treated a patient with both thymic carcinoma andthe plasma cell type of Castleman's disease whoexhibited highserum concentrations of IL-6, as well as focal segmental glo-merulosclerosis with nephrotic syndrome. To our knowledge,this case represents the first instance of such an association.

Case ReportA 63-year-old man was admitted to our hospital in January1999 because of edema and general malaise. Three monthsbefore admission, he noted edema in his legs and a gain inweight from 64 to 74 kg. He had no history of proteinuria.Physical examination revealed anasarca with massive ascites.No peripheral lymphadenopathy was present.On admission, laboratory results included: red blood cells,304xl04/pl; hemoglobin 9.3 g/dl; hematocrit, 28.3%; whiteblood cells, 14,800/jjI (neutrophils 77%, eosinophils 3%, ba-sophils 0%, lymphocytes 12%, monocytes 8%) ; platelets,27.2xlO4/|Lil; serum albumin, 0.9 g/dl; blood urea nitrogen, 20.6mg/dl; serum creatinine, 1.4 mg/dl; and C-reactive protein, 3. 1mg/dl. An antinuclear antibody test was positive (1:1,280,speckled pattern). The Wassermannreaction, complementstud-ies, rheumatoid factor, and assays for immunecomplexes andanti-neutrophil cytoplasmic antibody showed normal results.Tumormarkers including alpha-fetoprotein and carcinoem-bryonic antigen indicated no abnormalities except for the slightelevation of squamous cell carcinoma antigen (1.9 ng/ml, nor-mal <1.5). The serum concentration of IgG was elevated (2,070

From the Department of Internal Medicine, Nara Prefectural Mimuro Hospital, Kitakatsuragi-gun, *the First Department of Internal Medicine, Nara MedicalUniversity, Kashihara and **Department of General Medicine and Clinical Investigation, Nara Medical University, Kashihara

Received for publication December 3, 2001 ; Accepted for publication May 15, 2002Reprint requests should be addressed to Dr. Hideo Shiiki, the First Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara

634-8522

Internal Medicine Vol. 41, No. 10 (October 2002) 871

Matsumuraet al

mg/dl), but no monoclonalbandwas present either in serum orin urine. A 24-h urine collection contained 29.7 g of protein.The urinary sediment contained 10 tol9 red blood cells perhigh-power field and 2 to 3 granular casts per low-power field.The creatinine clearance was 35.7 ml/min. Serumand urinaryconcentrations of IL-6 were 44.3 pg/ml (normal, <4.0) and 14.8ng/day (normal, <5.0), respectively. A chest roentgenogramobtained upon admission showeda large, well-demarcated massoverlying the right hilum (Fig. 1). Computedtomography ofthe thorax revealed a large, low-density anterior mediastinalmass measuring 6 by 5 by 7 cm and projecting laterally (Fig.2). The mass showeda weak enhancementupon contrast me-dium administration.

Percutaneous renal biopsy was performed on the second

Figure 1. Frontal radiograph of the chest showing a largemass in the right upper mediastinum.

Figure 2. Computedtomographic scan showing weakly en-hanced tumor in the anterior mediastinum.

hospital day. Light microscopic findings indicated focal seg-mental glomerulosclerosis (Fig. 3). After radiologic screening

Figure 3. A glomerulus showing a segmental sclerosis andhypertrophic glomerular epithelial cells (periodic acid-Schiffstain, x250).

Figure 4. Biopsy specimen obtained from anterior mediasti-nal tumor showing proliferation of mature-appearing plasmacells in the interfollicular zones (HE stain, top xlOO, bottomx330).

872 Internal Medicine Vol. 41, No. 10 (October 2002)

Thymic Carcinoma with Castleman's Disease

Figure 5. The resected tumor is composed mainly of prolif-eration of atypical squamous cells. Scattered single cell kera-tinization is observed (HE stain, x400).

for potential sources of metastases, the tumor was biopsiedduring mediastinoscopy on the 38th hospital day. The biopsyspecimens were composed of lymphoid tissue exhibiting hy-perplasia of lymphoid follicles with prominent germinal cen-ters and marked capillary proliferation. Interfollicular zonescontained sheets of mature-appearing plasma cells (Fig. 4). Nolymphoepithelial lesion, hyalinized vessels or malignant cellswere noted. Plasma cell type of Castleman's disease was diag-nosed.

The patient initially withheld consent for operation, thusmethylprednisolone pulse therapy ( 1 g/day for 3 days) was giventhree times for nephrotic syndrome, followed by oral predniso-lone (40 mg/day). The treatment was partially effective, de-creasing proteinuria to 5 g/day. However, the mass increasedin size, serum concentrations of IL-6 rose to 78.9 pg/ml, andwhite blood cells increased to 26,800/p.l. A low-grade feverpersisted. The patient underwent tumor resection in July 1 999.Serum concentrations of IL-6 decreased to 16.6 pg/ml aftersurgery, but exceeded the normal value. Leukocytosis over20,000/(J.l persisted. One month later the patient developed righthemiplegia as a result of brain metastasis and died in October1999. No autopsy was performed.The tumor was located in the anterior mediastinum and com-pressed the superior vena cava and innominate veins, but didnot invade the lungs or pulmonary vessels. Grossly, the tumorwas well-circumscribed and measured 8 by 7 by 6.6 cm. Mi-croscopically, the tumor represented a proliferation of atypicalsquamous cells (Fig. 5). Single-cell keratinization and apoptoticcells were occasionally observed. Nointercellular bridges wereidentified. Necrotic foci were numerous. Clusters of plasmacells and lymphocytes were scattered within the tumor. Sheetsof plasma cells as seen in the biopsy specimen still were presentin mediastinal lymph nodes to which the squamouscell carci-noma had metastasized. Immunohistochemical staining wasperformed in formalin-fixed, paraffin-embedded sections. Avi-din-biotin complex method (DAKOLSAB+Kit, CA) was used

Figure 6. Immunoreactivity for IL-6 is scattered in squa-mous cell carcinoma (Immunostaining, x400).

with the following antibodies: goat polyclonal antibodies tohuman IL-6 (DAKO), 1 : 100; anti-immunoglobulin lambda lightchain monoclonal antibody (DAKO), 1 :3,000; anti-immuno-globulin kappa light chain monoclonal antibody (DAKO),1 :3,000. The sections for IL-6 staining were pretreated by mi-crowave exposure for 15 minutes. The color reaction was de-veloped with a 3,3'-diaminobenzidine-peroxide substrate.Meyer's hematoxylin was used for counterstaining. Immunore-activity for IL-6 was detected in the cytoplasm of cancer cells(Fig. 6). A number of plasma cells also were immunoreactivefor IL-6 and showed cytoplasmic expression of polyclonalimmunoglobulin light chains.

Dis cussion

The present case was the first to be described where an IL-6-producing thymic squamous cell carcinoma coexisted withthe plasma cell type of Castleman's disease. The patient alsohad focal segmental glomerulosclerosis with steroid-resistantnephrotic syndrome. He died of brain metastasis from the thy-mic squamous cell carcinoma.

Various human tumors produce IL-6 (4-7), including somesquamous cell carcinomas (6, 7). Previous studies demonstratedelevation of IL-6 in serum and tumor cell cytoplasmicimmunostaining for this cytokine in patients with squamouscell carcinomas arising in skin (2), uterine cervix (6), and

esophagus (7). In addition, Yoshizaki et al (8) reported a pa-tient with Castleman's disease whoshoweda decrease in se-rum IL-6 following surgical removal of the involved lymphnodes. The present patient continued to have high serum con-centrations of IL-6 after resection of the tumor and mediasti-nal lymph nodes, and ultimately developed brain metastasis.Although other hyperplastic lymph nodes involved byCastleman's disease might have been present as a source ofIL-6 in serum, we note a report from Ikeda et al (ll) of thymicsquamous cell carcinoma producing and secreting this cytokine,as have been described in other squamous cell carcinomas. In-

Internal Medicine Vol. 41, No. 10 (October 2002) 873

Matsumuraet al

deed, we demonstrated specific immunoreactivity in the squa-mous cancer cells and suspect that IL-6 may be a useful serummarker for metastasis or recurrence of thymic squamouscellcarcinoma.Nephrotic syndromewas the presenting symptomin thepresent patient. Renal complications of Castleman's diseaseare uncommon;approximately 40 cases have been reported ( 1 2-14). A variety of renal diseases have been represented includ-ing renal amyloidosis, interstitial nephritis, mesangial prolif-erative glomerulonephritis, and membranoproliferative glo-merulonephritis ( 1 2-14). However, focal segmental glomeru-losclerosis was found in only one previously reported patient(14). On the other hand, there is no reported case of coexistingthymic carcinomaand nephrotic syndrome. In our previousstudies concerning urinary IL-6 excretion in a variety of glom-erulonephritides, no significant association was observed withpatients with focal segmental glomerulosclerosis (15, 16). Al-though causal relationships and mechanisms remain unknown,our patient was interesting in terms of the potential associationof thymic carcinoma and/or Castleman's disease with focal

segmental glomerulosclerosis.The patient had shown persistent leukocytosis until death.Leukocytosis is not uncommonin the plasma cell type ofCastleman's disease (17, 18) and we administrated corticoste-roid to the patient. Nevertheless we can not exclude the possi-bility that the tumor might secrete granulocyte colony stimu-lating factor which is known to be produced by squamous cellcarcinomas of various organs (19, 20). Wetherefore suspectthat thymic squamouscell carcinoma and Castleman's diseasehad coexisted at presentation. Lack of squamous cell carci-noma in the biopsy specimen may be caused by sampling er-ror.

IL-6 is considered to play an important role in the patho-genesis of Castleman's disease and to be closely associatedwith lymphoid hyperplasia (8, 2 1 ). Hypergammaglobulinemia,increased concentrations of acute phase proteins, and variousclinical abnormalities are observed in that disease (8). In ourpatient, biopsy specimen findings and clinical features werecompatible with the plasma cell type of Castleman's disease,where capillaries do not necessarily showhyalinous thicken-ing (22). Thymic squamous cell carcinoma was diagnosed uponexamination of the resected tumor. While the combination ofCastleman's disease and squamous cell carcinoma have neverbeen reported previously, we suspect that IL-6 may have beenan important pathogenetic link in this patient.

Acknowledgements: The authors thank Prof. H. Nakamine of the Depart-ment of Laboratory Medicine at Wakayama Medical University, Wakayama,for valuable advice concerning pathologic diagnosis.

References

1) Kishimoto T. The biology of interleukin-6. Blood 74: 1-10, 1989.2) Kirnbauer R, Kock A, Schwarz T, et al. IFN-p2, B cell differentiationfactor 2 or hybridoma growth factor (IL-6) is expressed and released byhumanepidermal cells and epidermoid carcinoma cell lines. J Immunol

142: 1922-1928, 1989.

3) KawanoM, Hirano T, Matsuda T, et al. Autocrine generation and require-ment of BSF-2/IL-6 for human multiple myelomas. Nature 332: 83-85,

1988.

4) Miki S, Iwano M, Miki Y, et al. Interleukin-6 (IL-6) functions as an invitro autocrine growth factor in renal cell carcinomas. FEBS Lett 250:607-610, 1989.

5) Matsuguchi T, Okamura S, Kawasaki C, et al. Constitutive production ofgranulocyte colony-stimulating factor and interleukin-6 by a human lungcancer cell line, KSNY:Gene amplification and increased mRNAstabil-ity. Eur J Haematol 47: 128-133, 1991.

6) Takano H, Harigaya K, Ishii G, et al. Interleukin-6 (IL-6) production incarcinoma of the cervix. Arch Gynecol Obstet 258: 25-33, 1996.

7) Oka M, Yamamoto K, Takahashi M, et al. Relationship between serumlevels of interleukin 6, various disease parameters, and malnutrition inpatients with esophageal squamous cell carcinoma. Cancer Res 56: 2776-

2780, 1996.

8) Yoshizaki K, Matsuda T, Nishimoto N, et al. Pathogenic significance ofinterleukin-6 (IL-6/BSF-2) in Castleman's disease. Blood 74: 1360-1367,

1989.

9) Chung DA. Thymic carcinoma-analysis of nineteen clinicopathologicalstudies. Thorac Cardiov Surg 48: 114-119, 2000.

10) Morgenthaler TI, Brown LR, Colby TV, et al. Thymoma. Mayo Clin Proc68: 1110-1123, 1993.

1 1) Ikeda T, Kawakami K, Fujita J, et al. Thymic carcinoma associated witha high serum level of interleukin 6 diagnosed through the evaluation forasymptomatic elevation of acute-phase reactants. Intern Med37: 414-

416, 1998.

12) Akimoto H, Shirai M, Usutani S, et al. Membranoproliferative glomeru-lonephritis-like lesion with fibrillary deposition associated with multi-centric Castleman's disease. Jpn J Nephrol 40: 301-308, 1998.

13) Keven K, Nergizoglu G, Ates K, et al. Remission of nephrotic syndromeafter removal of localized Castleman's disease. AmJ Kidney Dis 35: 1207-

1211, 2000.

14) Kato Y, Kobayashi H, Mihara H, et al. Ticlopidine treatment in idiopathicplasmacytic lymphadenopathy with polyclonal hyperimmunoglobulinemiaaccompanied by nephrotic syndrome. Intern Med31: 504-507, 1992.

15) Horii Y, Muraguchi A, Iwano M, et al. Involvement of IL-6 in mesangialproliferative glomerulonephritis. J Immunol 143: 3949-3955, 1989.

16) Horii Y, Iwano M, Hirata E, et al. Role of interleukin-6 in the progressionof mesangial proliferative glomerulonephritis. Kidney Int Suppl 39: S7 1-

75,1993.

17) Keller AR, Hochholzer L, Castleman B. Hyaline-vascular and plasma-cell types of giant lymph node hyperplasia of the mediastinum and other

locations. Cancer 29: 670-683, 1972.18) McCarty MJ, Vukelja SJ, Banks PM, et al. Angiofollicular lymph nodehyperplasia (Castleman's disease). Cancer Treat Rev 21: 291-310, 1995.

19) Sato N, Asano S, Ueyama Y, et al. Granulocytosis and colony-stimulatingactivity (CSA) produced by a human squamous cell carcinoma. Cancer43: 605-610, 1979.

20) Sato K, Mimura H, Han DC, et al. Production of bone-resorbing activityand colony-stimulating activity in vivo and in vitro by a human squa-mous cell carcinoma associated with hypercalcemia and leukocytosis. JClin Invest 78: 145-154, 1986.

21) Palestro G, Turrini F, Pagano M, et al. Castleman's disease. Adv ClinPath 3: ll-22, 1999.

22) Frizzera G. Castleman's disease and related disorders. Semin Diagn Pathol5: 346-364,1988.

874 Internal Medicine Vol. 41, No. 10 (October 2002)