J Cancer Res Clin Oncol (1992) 118:147-151
C /icer esearch Clinical9 @ Springer-Verlag1992
Cellular variant of extraskeletal myxoid chondrosarcoma of abdominal w a l l - a case report with comparative immunohistochemical study on cartilaginous collagenous proteins in various myxoid mesenchymal tumors * Yoshimichi Ueda, Yasnnori Okada, and Isao Nakanishi Department of Pathology, School of Medicine, Kanazawa University 13-1 Takara-machi, Kanazawa City, Ishikawa 920, Japan Received 12 August 1991/Accepted 17 September 1991
Summary. A rare cellular variant o f recurrent extraskeletal myxoid chondrosarcoma occurring in the right lower abdominal wall of a 70-year-old man, is presented with emphasis on a characteristic distribution pattern of cartilaginous collagen proteins in the stroma. While the primary and the first recurrent tumors showed the typical histology o f extraskeletal myxoid chondrosarcoma, the later tumor, which recurred 14 years after the first resection, comprised mostly compact nodules of proliferating anaplastic cells with little mucoid stroma. Some areas presented a hemangiopericytomatous pattern. A few nodules possessed abundant myxoid stroma. Immunohistochemically, type II collagen was demonstrated in the stroma o f some cellular areas, and type VI collagen was intensely stained around individual tumor cells both in cellular and myxoid areas. In a comparative immunohistochemical study, the same distribution pattern of cartilaginous collagen proteins was observed only in skeletal myxoid chondrosarcomas, but not in other mesenchymal tumors with abundant myxoid stroma. These findings seem to support the cartilaginous nature of extraskeletal myxoid chondrosarcoma, and will facilitate the differential diagnosis of soft-tissue tumors with myxoid stroma.
Key words: Extraskeletal myxoid chondrosarcoma - Col-
extraskeletal myxoid chondrosarcoma have been well studied histochemically, and the cartilaginous nature of the tumor demonstrated (Kindblom and Angervall 1975; Fletcher et al. 1986). However, little attention has been paid, as yet, to coltagenous proteins, which are another major matrix component of the tumor stroma. Nowadays, at least 13 genetically distinct types of collagenous proteins have been recognized (Gordon et al. 1987; Miller and Gay 1987; Sandberg et al. 1989). Of these collagens, types II, IX, X, and XI, which are peculiar to the cartilaginous matrix (except for intervertebral disc and vitreous substance) (Miller and Gay 1987), and type VI, which is not specific to cartilage but shows a characteristic territorial distribution in cartilaginous tissue (Ayad et at. 1984; Ueda and Nakanishi 1989; Ueda et al. 1990), seem to be markers of cartilaginous differentiation. Recently we observed a case of extraskeletal myoxid chondrosarcoma that eventually developed into a rare highly cellular variant when recurring after 14 years. This peculiar case is presented with emphasis on a characteristic distribution pattern of types II and VI collagen in the stroma, unlike the patterns seen in various myxoid bone and soft-tissue tumors, which must be differentiated from extraskeletal myxoid chondrosarcoma.
l a g e n - Immunohistochemistry
Introduction Extraskeletal myxoid chondrosarcoma is a rare soft-tissue sarcoma, which produces abundant myxoid stroma (Enzinger and Weiss 1989). The proteoglycans in * Dedicated to Professor Dr. E. Grundmann on the occasion of his 70th birthday Offprint requests to: Yoshimichi Ueda, Mfinster Universi~t, Gerhard-Domagk Institut fiir Pathologie, Domagkstr. 17, W-4400 Mtinster, FRG
A 70-year-old man complained of a recurrent tumor in the right lower abdominal wall on January 19, 1987. His first admission had been in September 1973, when a large egg-sizedtumor, localizedjust beneath the fascia of the right external oblique muscle, was excised. Nine years later, two small nodules, which occurred at both ends of the operation scar, were resected. In May 1986, he noticed again a firm nodule in the right lower abdominal wall, which gradually increased in size and caused pain. A physical examination on admission revealed a potato-shaped firm mass attached to the spermatic cord at the right side of the pubic bone. The inguinal lymphnode was not swollen, and no distant metastasis was found radiologically. Wide excision of the tumor with the right spermatic cord and scrotal content was performed on January 22, 1987. He is well, without disease 4 years later.
Materials and methods Formalin-fixed and paraffin-embedded tumor tissues were subjected to hematoxylin and eosin staining, periodic acid/Schiff reaction with and without diastase digestion, alcian blue staining with and without testicular hyaluronidase digestion, silver impregnation, and immunostainings. The avidin-biotin method (Hsu et al. 1981) was used for immunostaining by antibodies against S-100 protein (Funakoshi, Japan, 1:3000), PKK1 cytokeratin (Labsystems, Finland, 1 : 50), and types II and VI collagen (our laboratory, 1 : 20 and 1:100). Monospecificities of antibodies to types II and VI collagen were assured by inhibition enzyme-linked immunosorbent assay tests in the previous studies (Oda et al. 1988; Ueda and Nakanishi 1989). For types II and VI collagen, deparaffinized sections were pretreated with 0.01% protease type XXIV (Sigma Chemical Company, St. Louis, Mo.) and 0.05% bovine testicttlar hyaluronidase (Sigma Chemical Company) as previously described (Ueda and Nakanishi 1989; Ueda et al. 1990). For a comparative study, three myxoid liposarcomas, three myxoid-type malignant fibrous histiocytomas, three chordomas, two skeletal myxoid chondrosarcomas, two ossifying fibromyxoid tumors of soft tissue, two myxoid malignant schwannomas, and one intramuscular myxoma were immunostained using the same antibodies as described above. Clinical and pathological information on those cases is summarized in Table 1.
surrounded by a b u n d a n t weakly basophilic m u c o i d m a trix (Fig. 1). The t u m o r recurring later s h o w e d multiple lobules separated by thin fibrous septa. M o s t lobules contained a highly cellular proliferation o f appreciably larger r o u n d or o v o i d - s h a p e d cells with vesicular nuclei, p r o m i n e n t nucleoli and eosinophilic cytoplasm (Fig. 2).
Fig. 1. Photomicrograph of the primary tumor showing small polygonal and short-spindle cells arranged in cords and small nests within an abundant mucoid stroma (hematoxylin/eosin, x 150)
Macroscopicfindings The p r i m a r y t u m o r was an irregular-shaped mass, sized 7.0 x 4.0 x 4.0 cm. A cut surface appeared gelatinous and lobulated with some foci o f hemorrhage. The first recurrent t u m o r consisted o f two nodules, up to 1.8 c m in the m a x i m u m diameter, along the previous operation scar. The newly recurrent tumor, measuring 7.0 x 5.0 x 5.0 cm, showed a multinodular and s o m e w h a t m y x o m a t o u s appearance with irregular margins. It contained areas o f h e m o r r h a g e and necrosis.
Microscopicfindings The p r i m a r y and the first recurrent t u m o r s consisted o f small polygonal or short-spindle cells with eosinophilic cytoplasm arranged in cords, small nests, or whorls, and
Fig. 2. Photomicrograph of the newly recurrent tumor showing diffuse proliferation of larger tumor cells with vesicular nuclei. Extracellular matrix is scarce. Arrows indicate mitoses (hematoxylin/ eosin, • 150)
Table 1. Various myxoid mesenchymal tumors examined ~
a M, male; F, femal; G, grade; L, left; R, right
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
60 F 46 F 51 M 48 'M 70 'M 76 'F 72 'F 37 'F 39 'F 77 'M 69 'F 42 'M 73 'M 19 'F 78 'F 17 'F
R distal femur L ischium Sacrum Sacrum Sacrum Buttock Buttock Retroperitoneum Retroperitoneum R knee Abdominal wall Retroperitoneum Chest wall L elbow Retroperitoneum R upper arm
Skeletal myxoid chondrosarcoma G2 Skeletal myxoid chondrosarcoma G1 Chordoma Chordoma Chordoma Ossifying fibromyxoid tumor Ossifying fibromyxoid tumor Myxoid liposarcoma Myxoid liposarcoma Myxoid liposarcoma Myxoid malignant fibrous histiocytoma Myxoid malignant fibrous histiocytoma Myxoid malignant fibrous histiocytoma Myxoid malignant schwannoma Myxoid malignant schwannoma Intramuscular myxoma
149 Some areas comprised compact proliferating round cells interspersed by irregular-shaped blood vessels, mimicking hemangiopericytoma. Stroma was scarce in m o s t nodules except for a few nodules showing a histology similar to that of the primary tumor. Mitoses were frequently observed (3-4/10 high-power fields) and vascular invasion was noticed in some areas. N o definite cartilaginous element was detected in the primary or recurrent tumors. T u m o r cells presented a diastase-labile, periodic acid/Schiff-positive reaction. The myxoid matrix was positive for alcian blue staining, which was only partially digested with testicular hyaluronidase. Reticulin fibers were recognized between t u m o r cells in the cellular portions, whereas only little reticular fiber was seen in areas rich in mucoid substance.
Immunohistochemieal findings Immunohistochemical findings are summarized in Table 2. In extraskeletal myxoid chondrosarcoma, a positive immunoreaction to type II collagen was present between t u m o r cells in some cellular areas (Fig. 3a). It was absent in areas rich in myxoid substance. Type VI collagen was localized predominantly around individual t u m o r cells in cellular as well as in myxoid areas (Fig. 3 b, c). In other myxoid mesenchymal tumors, type II collagen was demonstrated only in the stroma of skeletal myxoid c h o n d r o s a r c o m a and chordoma. Although type VI collagen was demonstrated in most myxoid tumors examined, a peculiar pericellular localization was found only in skeletal myxoid chondrosarcomas. In other myxoid tumors, type VI collagen appeared in fibrous distribution in the stroma, except for the c h o r d o m a where it was found along t u m o r cell cords. S-100 protein was
Table 2. Different immunostaining patterns between the current case and various myxoid mesenchymal tumors Myxoid mesenchymal tumors
Type II Type VI
Extraskeletal myxoid chondrosarcoma (current case) Skeletal myxoid chondrosarcoma (2 cases) Chordoma (3 cases) Ossifying fibromyxoid tumor (2 cases) Myxoid liposarcoma (3 cases) Myxoid malignant fibrous histiocytoma (3 cases) Myxoid malignant schwannoma (2 cases) Myxoma (1 case)
" S-100 protein; CK, cytokeratin b Positive in predominantly pericellular regions positive in t u m o r cells of extraskeletal and skeletal myxoid chondrosarcomas, chordomas, ossifying fibromyxoid tumors of soft tissue, and malignant schwannomas. In extraskeletal myxoid chondrosarcoma, the positive reaction was mainly intranuclear. A weak and inconstant positive reaction for S-100 protein was recognized in myxoid liposarcomas. Cytokeratin was positive only in the t u m o r cells o f chordomas.
Discussion Extraskeletal myxoid chondrosarcoma, which was first described by Stout and Verner (1953), and identified as
Fig. 3. Immunostaining with antibodies to type II collagen (a), type VI in myxoid area (b), and type VI in cellular areas (e). a Positive immunoreaction is recognized between tumor cells in cellular area ( • 300); b, e intense immunoreaction is localized mainly around individual tumor cells ( x 300)
a clinicopathological entity by Enzinger and Shiraki (1972), is characterized by a multinodular gelatinous mass composed of small tumor cells arranged in cords and strands separated by abundant mucoid stroma. In the present case, the primary and the first recurrent tumors had shown the typical morphology of extraskeletal myxoid chondrosarcoma as mentioned above, whereas the newly recurrent tumor mainly comprised compact, proliferating, large anaplastic tumor cells with little mucoid stroma. Thus, the current tumor can be subclassified as a cellular variant of extraskeletal myxoid chondrosarcoma, which is known to result in a poorer prognosis than the conventional tumor (Dardick et al. 1983; Enzinger and Shiraki 1972). In the current tumor, moreover, some areas show a hemangiopericytomatous pattern. Although no definite cartilage component like that in mesenchymal chondrosarcoma was detected in the current case, the histological expression of a hemangiopericytomatous pattern (which is frequently seen in mesenchymal chondrosarcoma) may imply some histogenetic relationship of extraskeletal myxoid chondrosarcoma to mesenchymal chondrosarcoma, as proposed by Dardick et al. (1983). Among the various mesenchymal tumors with abundant myxoid stroma, extraskeletal myxoid chondrosarcoma has a striking histological resemblance to chordoma, and to skeletal myxoid chondrosarcoma as well. The present comparative immunohistochemical study demonstrated the localization of type II collagen in the stroma not only of extraskeletal and skeletal myxoid chondrosarcomas, but also of chordomas. All of them were also positive for S-100 protein. Chordoma, however, shows a positive reaction to cytokeratin. Expression of other epithelial markers, such as epithelial membranous antigen, carcinoembryonic antigen, secretory component, and e-fetoprotein, was also reported in the previous immunohistochemical studies of chordoma (Abenza and Sibley 1986; Bouropoulou et al. 1989). Such epithelial and mesenchymal "bimodal" differentiation suggests that chordoma originates from persistent remnants of the notochord. On the other hand, cytokeratin was negative in extraskeletal and skeletal myxoid chondrosarcomas. Thus, the immunohistochemical demonstration of type II collagen in the stroma of the present case may be taken as further evidence for a chondrogenic differentiation of extraskeletal myxoid chondrosarcoma, in addition to previous indications by histochemical (Kindblom and Angervall 1975; Fletcher et al. 1986) and electron-microscopic investigations (Weiss 1976; Tsuneyoshi et al. 1981). With regard to type VI collagen, the peculiar pericellular localization in extraskeletal myxoid chondrosarcoma is somewhat intriguing, because type VI collagen was previously shown to exist characteristically in pericellular regions in normal and neoplastic cartilaginous tissues (Ayad et al. 1984; Ueda and Nakanishi 1989; Ueda et al. 1990). Furthermore, in the present comparative immunohistochemical study, the peculiar pericellular distribution pattern of type VI collagen was observed only in skeletal myxoid chondrosarcoma. In other myxoid tumors, type VI collagen was found in diffuse fibrous distribution in
the stroma, except in chordoma, where type VI collagen was demonstrated predominantly along tumor cell cords. Therefore, the peculiar pericellular localization of type VI collagen in the present case of extraskeletal myxoid chondrosarcoma also supports its chondrogenic nature, suggesting that an immunohistochemical approach using antibodies to collagen types VI and II would be helpful in the differential diagnosis of myxoid mesenchymal tumors. The functional repertoire of type VI collagen is insufficiently known so far: it is suggested that the collagen VI filament network, acting as a link between large macromolecules and the filaments, could aggregate to form fibrous long-spacing (FLS) structures (Bruns et al. 1986; Keene et al. 1988; Okada et al. 1990). In skeletal and extraskeletal myxoid chondrosarcomas, electron microscopy reveals FLS in the immediate vicinity of tumor cells (Weiss 1976). Some areas of strong immunoreactivity to type VI collagen in the pericellular space of both skeletal and extraskeletal myxoid chondrosarcomas may correspond to FLS, although that remains to be evaluated by immunoelectron microscopy. It is noteworthy that type II collagen was localized not in ordinary areas with abundant mucoid stroma, but in predominantly cellular areas. The negative results in ordinary myxoid areas might be due to the masking of epitopes by extensive proteoglycan. In the present study, however, a careful pretreatment with hyaluronidase as well as protease was performed in order to expose epitopes for collagenous proteins. It is speculated that the tumor cells of extraskeletal myxoid chondrosarcoma in the ordinary myxoid areas switched off the production of type II collagen in response to the overproduction ofproteoglycan, while being usually well coordinated for the normal development of cartilaginous tissue. Acknowledgement. We are grateful to Prof. Albert Roessner, of Gerhard-Domagk Institut ffir Pathologie, Mfinster Universit~it, for his critical reading of this manuscript.
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