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Histiocytoid endothelial cells in a malignant schwannoma
Case Studies
HISTIOCYTOID ENDOTHELIAL CELLS IN A M A L I G N A N T S C H W A N N O M A K. DEScIIRYVER-KEcSKEMETI,MD, D.J. SANTA CRUZ, MD, AND ~|. KYRIAKOS, MD
Unusual vascular lining cells within a malignant schwannoma prompted a comparative study of these cells and the endothelial cells in cases of histiocytoid hemangiomas. The endothelial cells in all cases showed similar morphologic and immunohistochemical features. Such endothelial cells were not found in the capillaries of a pyogenic granuloma or in those of developing rat skin. It is postulated that these distinctive endothelial cells may be more widely distributed than was previously thought and that morphologic changes associated with these cells may be induced by vasoactive substances. Hum Pathol 13:173-177, 1982. D u r i n g the electron microscopic e x a m i n a t i o n o f a malignant schwannonla, distinctive cells were found lining the vascular channels o f the tumor. T h e most striking feature o f these cells, which projected into the vascfilar lnmens in a hobnail fashion, was tile presence o f an a b u n d a n t cytoplasm filled with arrays o f cytoplasmic filaments often located in an apical position. T h e morphology o f these cells was thought to be similar to that o f cells which Rosai et a l ) recently described in a g r o u p o f vascular lesions a n d for which they use the term "histiocytoid e n d o t h e l i a l cells." F o u r e x a m p l e s o f histiocytoid h e m a n g i o m a - - t h r e e from the skin and o n e from b o n e - - w e r e then examined by light and electron microscopy, antl a pyogenic g r a n u l o m a a n d d e r m a l vessels in neonatal rats were also e x a m i n e d to determine w h e t h e r "histiocytoid endothelial cells" were present in all conditions characterized by proliferating blood vessels. T h e n a t u r e o f these cells was also studied by means o f an immunohistochemical staining method for endothelial cells. T o o u r knowledge, these distinctive ceils have not bcen studied in conditions other than the histiocytoid hemangiomas. M A T E R I A L S AND M E T H O I ) S Tissue for light microscopy was fixed in neutral buffe r e d formalin and processed t h r o u g h paraffin in the usual m a n n e r . In addition to hematoxylin and eosin stains, deparaffinized sections were treated with antibodies to factor V I I I - a s s o c i a t e d antigen,* a m a r k e r for endothelial ceils, using the unlaheled antibody-enzyme (peroxidaseantiperoxidase; PAP) p r o c e d u r e o f Sternberger et al. z Tissue for electron microscopy was fixed in 2.5 per cent glutaraldehyde and processed routinely. Uranyl acetateand lead citrate-stained sections were viewed by means o f a Philips 300 microscope. Newborn Wistar rats were rapidly anesthetized with ether, and a strip o f skin was excised from Received from the Division of Surgical Pathology, Department of Pathology, Washington University School of Medicine, St. Louis, Mo. Address correspondence and reprint requests to Dr. DeSchryver-Kecskemeti, Division of Surgical Pathology, Barnes llospital, St. l~mis. MO 63110. * Behring Diagnostics, Somerville, NJ.
the back o f each between the scapulae and processed for light and electron microscopy in the same way. RESULTS
Light
Microscopy
T h e appearance o f tile vascular component in tile various lesions studied by conventional light microscopy was similar and c o r r e s p o n d e d to Rosai's description' o f the histiocytoid e n d o t h e l i a l cell. Essentially, the p r o l i f e r a t i n g blood vessels were lined by large cuboid-appearing endothelial cells, which p r o t r u d e d into the vascular lumens. These features are illustrated in figure 1, A and B. Sections o f ttle malignant schwannoma (fig. IA) showed a fibrosarcomatous stroma in which dilated blood vessels were scattered. T h e extreme endothelial proliferation scen in histiocytoid hemangiomas was not noted on light microscopic examination. However, sections 1-nficron thick a n d stained with toluidine blue showed vessels with plum~ lining cells that bulged into the vascular lumens (fig. IC). A b u n d a n t cytoplasm with nuclei showing great variability in size and shape were seen. T h e nuclear membrane was often irregular, with indentations and folds. I'rominent nucleoli were present, and cytoplasmic vacuolization was often noted. T h e endothelial cells in the histiocytoid h e m a n g i o m a s showed similar features. In sections o f developing rat skin and in the pyogenic g r a n u l o m a , endothelial cells projecting into the vascular lumens were observed and could not be distinguished from some o f the endothelial cells noted in the histiocytoid hemangiomas. Imnlunocytochemical stains, using antibodies to factor VIII-associated antigen, yielded a positive reaction in the cytoplasm o f the endothelial cells o f the malignant schwannoma (fig. 1D) and the histiocytoid hemangiomas. Endothelial cells o f n o r m a l - a p p e a r i n g blood vessels located in the periphery o f all the lesions also stained, as did the endothelial cells o f the pyogenic granuloma, but the developing blood vessels o f the rat skin did not stain. T h e various features found in these tissues are sumnmrized in table 1.
Electron
Microscopy
By electron microscopy, endothelial cells from tile various lesions could be divided into two distinct groups. In one group, the fine structural features o f the cells seen in tile atypical blood vessels o f the malignant schwannoina were identical to those in the histiocytoid helnangiomas (figs. IE, 2). T h e endothelial ceils had ample cytoplasm, which p r o t r u d e d deeply into tile lumen o f the vessels, with p r o m i n e n t surface projections. T h e nuclei showed muhiple infoldings, occasional p r o m i n e n t nuclcoli, and regularly distributed chromatin. T h e Uslml cytoplasmic organelles such as m i t o c h o n d r i a , e n d o p l a s m i c reticuhnn, WeibelPalade bodies, and pinocytotic vesiclcs were p r e s e n t in m o d e r a t e n u m b e r s , as was a well-developed Golgi ap-
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173
HUMAN
PATHOLOGyIVOLUME
13, N U M B E R 2
February 1 9 8 2
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Figure 1. A, dilated vascular channels in a malignant schwannoma. Endothelial cells (il~set) are some~vllat atypical and protrude into the vascular lumen. (tlematoxylin-eosin stain. • b~et • B, histiocytoid Ilemangioma of l• P,lood vessels are lined with large endothelial cells protruding into the vascular lumen (Hematoxylin-eosin stain, x 150; inset x350.) C, one-micron section of the malignant schwanuoma, which shows endothelial cells projecting into vascular lumens in a hobnail pattern. (Toluidine blue. x600.) D, staining o f these endothelial cells in the malignant schwannoma, which yields a positive reaction for factor VIII-associated antigen. This consists of a granular dark reaction product in the cytoplasm of the vascular lining cells. (PAP stain, x600.) E, on electron microscopy, filaments, abtmdant cytoplasmic organelles, and ce,ltrioles fill the apical supranuclear portion of the endothelial cells. (Uranyl acetate-lead citrate stain. x 16,000.)
174
CASE STUI)IES TABLE 1. SUMMARY OF FEATURES OBSERVED BY LIGHT A N D ELECTRON MICROSCOPY IN TIIE E N D O T H E L I U M OF M A L I G N A N T S C H W A N N O M A , HISTIOCYTOID H E M A N G I O M A , PYOGENIC G R A N U L O M A , A N D N E O N A T A L R A T SKIN Endothelium in:
Malignant Schwannoma
Histioeytoid Hemangioma
Pyogenic Granuloma
Neonatal Rat Shin
+ + +
+ + +
+ + +
+ + +
+
+
+
++ +++ + + _
++ +++ + .4-
++ 4+++
Light Microscopy lntraluminal cytoplasmic projection Abundant eosinophilic cytoplasm Nuclear variability Factor VllI-associated antigen react ivity
Electro~, Microscopy Intraluminal projection with active surface contour Cytoplasmic filaments Centrioles Lysosomes Ribosomes. + + + Major cytoplasmic component. + Present but rare. - Absent.
+ + Significant component.
paratus a n d n u m e r o u s lysosolnes. Prominent intercellular j u n c t i o n s were present (fig. 2B). In addition, bundles and whorls of filaments of intermediate size (7 to 11 nm), which made u p the bulk of the cytoplasm, were often observed in apical positions. In areas where the intraluminal cytoplasmic protrusion was not in the plane of section of the n u cleus, tim entire cytoplasm consisted of these filaments. Centrioles were regularly seen in these cells. Thcse cells were always invested by a basemeut m e m b r a n e that was often multilayered. Pericytes were present and u n r e m a r k able. T h e maligmant schwannoma showed, in addition to the distinctive endothelial cells, n u m e r o u s widely scattered cells in the t u m o r stronm, close to vessels, which were packed wittt m e m b r a n e - a n d n o n m e m b r a n e - l ) o u n d cytoplasmic granules. These were variously electron dense and of various shapes and sizes and some had typical featnres of mast cells, while others were similar to nenrosecretory-type cells. Constituting a distinctly different group (table 1), the endothelial cells in the vessels of the developing rat skin, as well as those lining the capillaries o f the pyogenic granuloma, had cytoplasmic intraluminal projections that were ahvays in the plane of section of the nuclens, appearing triangular. T h e cytoplasm was scanty, with an almost total absence of cytoplasmic filaments, and it contained an abundance o f ribosomes and endoplasmic reticulum. Lysosomes were rarely seen. DISCUSSION By light microscopy, u n u s u a l vascular changes have been noted in malignant s c h w a n n o m a s ) These consist of blood vessels lined with atypical-appearing cells that were believed to represent t u m o r cells. T h e r e Ires been no systematic electron microscopic description of these cells, q'he single electron micrograph illustrated in Waggener's l)aper on nerve sheath tumors 4 shows p l u m p endothelial cells c o n t a i n i n g a b u n d a n t cytoplasmic organelles a n d tolded nuclei. As in o n r case, cytoplasmic filaments were also prominent. That tim atypical ceils lining the blood vessels o f these nerve sheath tumors do not always represent t u m o r cells, as was originally believed,~ is supported by the fact timt tim cells lining the vascular spaces in o u r case stained with antibodies to factor VIII-associated antigen. This m a r k e r for endothelial cells, which normally elaborates some of the components to factor VIII, even in i n ' v i t r o
++ -'+++
+ Present.
c o n d i t i o n s , has b e e n s u c c e s s f u l l y used to i d e n t i f y endotheliunt-derived cells in tissue sectiolts3 T i m light and electron nticroscopic features in o u r cases o f histiocytoid h e m a n g i o m a were similar to those previottsly described and reviewed by Rosai et al.t; they include an increase in the n u m b e r of cytoplasmic organelles. Tim unique electron microscopic feature of these endothelial cells, however, is the abtmdance of cytoplasmic filaments. 6"r In respect to this feature, as well as to all the otlter morphologic features found, including a positive reaction for factor VII I-associated antigen, the endothelitnn in the vessels of the malignant schwannoma was identical to tlm vascular lining cells of the histiocytoid henmngiomas. T i m positive reaction of tlte lfistiocytoid endothelial cells for factor V I I I - a s s o c i a t e d a n t i g e n has not been previously reported. T h e significance of the a b t m d a n t cytoplasmic filaments in these cases is not known. Tim filaments appear instrumental in modifying cellular shape in that the endothelial cells "stand up" and orient their long axes perpendicular to the wall of tim vessel instead o f parallel to the direction of the blood flow. 7 Tim usual presence of cytoplasmic filaments in endothelial cells has been regarded by some authors, including Ma.ino et al.,s as evidence of botlt cellular smooth muscle differentiation and contractile capability. The small bundles of filaments are typically located in a perinuclear position when tim cell is at rest. When tim "contractile" endothelial cell described by Majno is seen in what is interpreted as the contracted state, it differs from tim histiocytoid endothelial cell. It protrudes into the vascular hlmen only in the plane o f section o f the n u c l e u s , the cytosol is p u s h e d into pseudopodia at the a b h u n i n a l surface, and organelles, including the few bundles of filaments, are gathered in the subuuclear space. T h e histiocytoid endothelial cell differs also from endothelial cells described in newly formed vessels of such angiomatous lesions as pyogenic g r a n u l o m a mainly by the near-absence o f filaments in the latter. 6 T i m significance of the centrioles that we regularly observed reinains unknown. T h e y have been described in endothelial cells of lymphatic channels but were not considered "markers" for that cell. s Ztte histogenesis of tbe histiocytoid lmmangiomas is not currently known. Similar endothelial cells are known to
175
HUMAN
PATItOLOGY--VOLUME
13, N U M B E R 2
Febntary 1982
Figure 2. A, endothelial cells from the malignant schwannoma. The cells "stand up," projecting into tile ~ascular lumina. Whorls of cytoplasmic filaments are a d o m i n a n t feature. (Uranyl acetate-lead citrate stain, x20,000.) B, endothelial cells of tile malignant schwannoma show intrahnninal c)toplasmic projectious filled with coarse filaments, some o f which show lveriodic condensations (arrows). Intercellular junctions and a well-developed basement m e m b r a n e are seen. (Uranyl acetate-lead citrate stain, x32,000.)
176
CASE STUDIES exist in lymph.nodes t~ and liver, H and they have been found in a nmlignant schwannoma, in urticaria pigmentosa, v~ and in e x p e r i m e n t a l Iiyl~ertensionta----conditionsall known to produce vasoactive substances. These distinctive endothelial ceils occur, therefore, in very diverse clinical conditions. Whether the histiocytoid endothelial cells represent a proliferation of a subset of special endothelial cells tlmt are nornmlly present or the metabolic activation of "normal" endothelial cells by some vasoactive substances remains to be settled. T h e physiologic relevance of the morphologic observations and their relation to the genesis of the lesion may not become clear until an in vitro test system becomes available to study morphologic clmnges inducible in endothelial cells by vasoactive substances. In the meantime, the positive identification o f this special endothelial Cell may require electron microscopy in some lesions, because look-alike llorid endothelial cells scen by light microscopy may correspond to a different and, by electron microscopy, distinct constellation oforganelles. We agree with Rosai et al? tlmt the distinctive "histiocytoid endothelial cell" ma t, occur more commonly than was previously suspected.
REFERENCES I. Rosai J, Gohl J, Landy R: The histioc)toid hemangiomas, llum i'athol 10:107, 1979. 2. Sternberger LA, llardy PII Jr, Cuculis JJ, et ah The nnlaheled antibody.enzyme method of immunohistochemistry: preparation and properties of soluble antigen-antibody complex (horseradish peroxidase-antihorseradish peroxidase) and its use in identification of spirochetes. J llistochem 18:315, 1970. 3. Guccion JG, Enzinger FM: Malignant schwannoma associated with Von Rechlinghausen's neurofibromatosis. Virchows Arcb (l'athol Anat) 383:43, 1979. 4. WaggenerJD: Uhrastructure ofbenign peripheral nerve sheath tumors. Cancer 19:699, 1966. 5. Mukai K, Rosai J, Burgdorf WIIC: Localization of factor Vlll-related antigen in vascular endothelial cells using an immunnperoxidase method. Am J Surg Pathol 4:273, 1980. 6. Majno G, Jorls I: Endotbelium 1977: a review. Adv Exp Med Biol 104:169, 1978. 7. Thorgeirsson G, Robertson At.: The vascular endothelium: pathobiolo#c significance. Am J Pathol 93:803, 1978. 8. Majno G, Shea SM, Leventhal M: Endothelial contraction induced by histamine-type mediators. J Cell Biol 42:6-17, 1969. 9. Lauwcryns JM, Boussae WL: Striated filamentous bundles associated with centrioles in pulmonary lymphatic endothelial cells. J Uhrastruct Res 42:25, 1973. 10. Anderson ND, Anderson AO, Wyllie RG: Microvascular changes in lymph nodes draining skin allografts. Am J Pathol 81:i31, 1975. l 1. Johannessen JV: The Liver. In Johannessen JV (ed): Electron Microscopy in Iluman Medicine. McGraw-tlill Book Co., 1979, p 17. 12. Ludatscber RM: Ultrastructure of human dernml blood scssels with a special reference to the endothelial filaments. Virchows Arch (Cell Pathol) 27:347, 1978. 13. Still WJS, Dennisnn S: Tim arterial endothelium of the hypcrtensive rats. Arch Pathol Lab Med 97:337, 1974.
ACKNOWLEI)GMENTS We wish to thank Dr. Waher C. Bauer and Dr. Joseph R. Williamson for advice in the preparation of this m a n n script.
PELIOSlS OF THE SPLEEN WITH RUPTURE ROGI.:R L. GARCIA, MD,* MATIIFI:'N K. KIIAN, MD,t AND RICIIARD B. BFRLIN, MD:[:
A case ofpeliosis of the spleen without apparent involvement of the liver or other organs is presented. The peliosis was discovered following rupture of the spleen after minimal trauma and was successfully treated by surgery. None of the common associations of peliosis was present (i.e., tuberculosis or intake of steroM compounds). Drug add#tion and chronic alcoholism were the only coexisting debilitating conditions exhibited by this patient, llum Pathol 13:177-179, 1982. Peliosis of the spleen is an extremely rare entity that is virtually always associated with peliosis of the liver. Peliotic changes of these organs have been described in association witlt anabolic steroids, oral contraceptives, anti pulmotmry tuberculosis. We report here a patient with peliosis of the spleen who was totally asymptomatic and without any known associated factors other than drug addiction and chronic alcoholism. She presented with a r u p t u r e d spleen and intraperitoneal hemorrhage following minimal trauma and was treated successfully. CASE REPORT A 48-year-ohl wonmn was admitted through the emergency rootn with left-upper-quadrant abdominal pain. She had fallen while intoxicated three days earlier a n d had * Assistant Attending Pathologist 1 Resident in Pathology ~t Chief Resident in Surgery Received from the Department of Pathology and Surgery, Beth Israel Medical Center, New York, NY, and Mount Sinai School of Medicine of the City University of New York. Address correspondence and reprint requests to Dr. Garcia, Deparmaent of l'athology, Beth Israel Medical Center, 10 Nathan D. Perhnan Place, New York, NY 10003.
struck her left lower ribs. Radiographs sttowed no fractures. She denied nausea or vomiting. Her medical history revealed chronic alcoholism as well as drug addiction. She had used heroin in tile past and had later received m e t h a d o n e as part o f a detoxification plan. Both of her parents died of tuberculosis, ahhot,glt she had never been treated for it and had no stigmata of the disease. T h e patient did not take any medications and had not taken steroids. She was, at this time, four years postmenopavsal and had never taken oral contraceptives. She had one normal child. Physical e x a m i n a t i o n revealed a n o r m a l - a p p e a r i n g heahhy woman. Her blood pressure was 100 m m Hg systolic and her pulse rate 100 beats/min. Her a b d o m e n was soft and not tender; there was no guarding, and bowel sounds were present. Serum amylase was normal, alkaline phosphatase 69 U/l, bilirubin 0.2 mg/dl, and SGPT 22 U/I. l'araceutesis was p e r f o r m e d , and gross blood r e t u r n e d . q'he patient's hematocrit was 29 per cent. An emergency laparotomy revealed a r u p t u r e d spleen with some fibrous adhesions between its capsule and the abdominal wall. T h e spleen was removed without diffictflty; during surgery the liver and pelvic organs were carefully examined for signs of trauma or hemorrhage a n d were fotmd to be completely u n r e m a r k a b l e on their external surfaces. T h e patient's postoperative course was without complication. When the pathologic examination of the removed spleen revealed the existence of peliosis, an extensive evahmtion of 9the patient was carricd out. It included a hepatic arteriogratn, C A T scan, tipper gastrointestinal series and barium enema studies, and intravenous pyelogratn; serum cortisol and testosterone as well as 17-hydroxy-corticosteroids and 17-ketosteroids in 24-hour urines were also evaluated. All these studies failed to reveal any other significant pathol-
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177
HISTIOCYTOID ENDOTHELIAL CELLS IN A M A L I G N A N T S C H W A N N O M A K. DEScIIRYVER-KEcSKEMETI,MD, D.J. SANTA CRUZ, MD, AND ~|. KYRIAKOS, MD
Unusual vascular lining cells within a malignant schwannoma prompted a comparative study of these cells and the endothelial cells in cases of histiocytoid hemangiomas. The endothelial cells in all cases showed similar morphologic and immunohistochemical features. Such endothelial cells were not found in the capillaries of a pyogenic granuloma or in those of developing rat skin. It is postulated that these distinctive endothelial cells may be more widely distributed than was previously thought and that morphologic changes associated with these cells may be induced by vasoactive substances. Hum Pathol 13:173-177, 1982. D u r i n g the electron microscopic e x a m i n a t i o n o f a malignant schwannonla, distinctive cells were found lining the vascular channels o f the tumor. T h e most striking feature o f these cells, which projected into the vascfilar lnmens in a hobnail fashion, was tile presence o f an a b u n d a n t cytoplasm filled with arrays o f cytoplasmic filaments often located in an apical position. T h e morphology o f these cells was thought to be similar to that o f cells which Rosai et a l ) recently described in a g r o u p o f vascular lesions a n d for which they use the term "histiocytoid e n d o t h e l i a l cells." F o u r e x a m p l e s o f histiocytoid h e m a n g i o m a - - t h r e e from the skin and o n e from b o n e - - w e r e then examined by light and electron microscopy, antl a pyogenic g r a n u l o m a a n d d e r m a l vessels in neonatal rats were also e x a m i n e d to determine w h e t h e r "histiocytoid endothelial cells" were present in all conditions characterized by proliferating blood vessels. T h e n a t u r e o f these cells was also studied by means o f an immunohistochemical staining method for endothelial cells. T o o u r knowledge, these distinctive ceils have not bcen studied in conditions other than the histiocytoid hemangiomas. M A T E R I A L S AND M E T H O I ) S Tissue for light microscopy was fixed in neutral buffe r e d formalin and processed t h r o u g h paraffin in the usual m a n n e r . In addition to hematoxylin and eosin stains, deparaffinized sections were treated with antibodies to factor V I I I - a s s o c i a t e d antigen,* a m a r k e r for endothelial ceils, using the unlaheled antibody-enzyme (peroxidaseantiperoxidase; PAP) p r o c e d u r e o f Sternberger et al. z Tissue for electron microscopy was fixed in 2.5 per cent glutaraldehyde and processed routinely. Uranyl acetateand lead citrate-stained sections were viewed by means o f a Philips 300 microscope. Newborn Wistar rats were rapidly anesthetized with ether, and a strip o f skin was excised from Received from the Division of Surgical Pathology, Department of Pathology, Washington University School of Medicine, St. Louis, Mo. Address correspondence and reprint requests to Dr. DeSchryver-Kecskemeti, Division of Surgical Pathology, Barnes llospital, St. l~mis. MO 63110. * Behring Diagnostics, Somerville, NJ.
the back o f each between the scapulae and processed for light and electron microscopy in the same way. RESULTS
Light
Microscopy
T h e appearance o f tile vascular component in tile various lesions studied by conventional light microscopy was similar and c o r r e s p o n d e d to Rosai's description' o f the histiocytoid e n d o t h e l i a l cell. Essentially, the p r o l i f e r a t i n g blood vessels were lined by large cuboid-appearing endothelial cells, which p r o t r u d e d into the vascular lumens. These features are illustrated in figure 1, A and B. Sections o f ttle malignant schwannoma (fig. IA) showed a fibrosarcomatous stroma in which dilated blood vessels were scattered. T h e extreme endothelial proliferation scen in histiocytoid hemangiomas was not noted on light microscopic examination. However, sections 1-nficron thick a n d stained with toluidine blue showed vessels with plum~ lining cells that bulged into the vascular lumens (fig. IC). A b u n d a n t cytoplasm with nuclei showing great variability in size and shape were seen. T h e nuclear membrane was often irregular, with indentations and folds. I'rominent nucleoli were present, and cytoplasmic vacuolization was often noted. T h e endothelial cells in the histiocytoid h e m a n g i o m a s showed similar features. In sections o f developing rat skin and in the pyogenic g r a n u l o m a , endothelial cells projecting into the vascular lumens were observed and could not be distinguished from some o f the endothelial cells noted in the histiocytoid hemangiomas. Imnlunocytochemical stains, using antibodies to factor VIII-associated antigen, yielded a positive reaction in the cytoplasm o f the endothelial cells o f the malignant schwannoma (fig. 1D) and the histiocytoid hemangiomas. Endothelial cells o f n o r m a l - a p p e a r i n g blood vessels located in the periphery o f all the lesions also stained, as did the endothelial cells o f the pyogenic granuloma, but the developing blood vessels o f the rat skin did not stain. T h e various features found in these tissues are sumnmrized in table 1.
Electron
Microscopy
By electron microscopy, endothelial cells from tile various lesions could be divided into two distinct groups. In one group, the fine structural features o f the cells seen in tile atypical blood vessels o f the malignant schwannoina were identical to those in the histiocytoid helnangiomas (figs. IE, 2). T h e endothelial ceils had ample cytoplasm, which p r o t r u d e d deeply into tile lumen o f the vessels, with p r o m i n e n t surface projections. T h e nuclei showed muhiple infoldings, occasional p r o m i n e n t nuclcoli, and regularly distributed chromatin. T h e Uslml cytoplasmic organelles such as m i t o c h o n d r i a , e n d o p l a s m i c reticuhnn, WeibelPalade bodies, and pinocytotic vesiclcs were p r e s e n t in m o d e r a t e n u m b e r s , as was a well-developed Golgi ap-
0046-81771821020010173 $ 1.00 9 w.
Sa ,der O,.
173
HUMAN
PATHOLOGyIVOLUME
13, N U M B E R 2
February 1 9 8 2
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Figure 1. A, dilated vascular channels in a malignant schwannoma. Endothelial cells (il~set) are some~vllat atypical and protrude into the vascular lumen. (tlematoxylin-eosin stain. • b~et • B, histiocytoid Ilemangioma of l• P,lood vessels are lined with large endothelial cells protruding into the vascular lumen (Hematoxylin-eosin stain, x 150; inset x350.) C, one-micron section of the malignant schwanuoma, which shows endothelial cells projecting into vascular lumens in a hobnail pattern. (Toluidine blue. x600.) D, staining o f these endothelial cells in the malignant schwannoma, which yields a positive reaction for factor VIII-associated antigen. This consists of a granular dark reaction product in the cytoplasm of the vascular lining cells. (PAP stain, x600.) E, on electron microscopy, filaments, abtmdant cytoplasmic organelles, and ce,ltrioles fill the apical supranuclear portion of the endothelial cells. (Uranyl acetate-lead citrate stain. x 16,000.)
174
CASE STUI)IES TABLE 1. SUMMARY OF FEATURES OBSERVED BY LIGHT A N D ELECTRON MICROSCOPY IN TIIE E N D O T H E L I U M OF M A L I G N A N T S C H W A N N O M A , HISTIOCYTOID H E M A N G I O M A , PYOGENIC G R A N U L O M A , A N D N E O N A T A L R A T SKIN Endothelium in:
Malignant Schwannoma
Histioeytoid Hemangioma
Pyogenic Granuloma
Neonatal Rat Shin
+ + +
+ + +
+ + +
+ + +
+
+
+
++ +++ + + _
++ +++ + .4-
++ 4+++
Light Microscopy lntraluminal cytoplasmic projection Abundant eosinophilic cytoplasm Nuclear variability Factor VllI-associated antigen react ivity
Electro~, Microscopy Intraluminal projection with active surface contour Cytoplasmic filaments Centrioles Lysosomes Ribosomes. + + + Major cytoplasmic component. + Present but rare. - Absent.
+ + Significant component.
paratus a n d n u m e r o u s lysosolnes. Prominent intercellular j u n c t i o n s were present (fig. 2B). In addition, bundles and whorls of filaments of intermediate size (7 to 11 nm), which made u p the bulk of the cytoplasm, were often observed in apical positions. In areas where the intraluminal cytoplasmic protrusion was not in the plane of section of the n u cleus, tim entire cytoplasm consisted of these filaments. Centrioles were regularly seen in these cells. Thcse cells were always invested by a basemeut m e m b r a n e that was often multilayered. Pericytes were present and u n r e m a r k able. T h e maligmant schwannoma showed, in addition to the distinctive endothelial cells, n u m e r o u s widely scattered cells in the t u m o r stronm, close to vessels, which were packed wittt m e m b r a n e - a n d n o n m e m b r a n e - l ) o u n d cytoplasmic granules. These were variously electron dense and of various shapes and sizes and some had typical featnres of mast cells, while others were similar to nenrosecretory-type cells. Constituting a distinctly different group (table 1), the endothelial cells in the vessels of the developing rat skin, as well as those lining the capillaries o f the pyogenic granuloma, had cytoplasmic intraluminal projections that were ahvays in the plane of section of the nuclens, appearing triangular. T h e cytoplasm was scanty, with an almost total absence of cytoplasmic filaments, and it contained an abundance o f ribosomes and endoplasmic reticulum. Lysosomes were rarely seen. DISCUSSION By light microscopy, u n u s u a l vascular changes have been noted in malignant s c h w a n n o m a s ) These consist of blood vessels lined with atypical-appearing cells that were believed to represent t u m o r cells. T h e r e Ires been no systematic electron microscopic description of these cells, q'he single electron micrograph illustrated in Waggener's l)aper on nerve sheath tumors 4 shows p l u m p endothelial cells c o n t a i n i n g a b u n d a n t cytoplasmic organelles a n d tolded nuclei. As in o n r case, cytoplasmic filaments were also prominent. That tim atypical ceils lining the blood vessels o f these nerve sheath tumors do not always represent t u m o r cells, as was originally believed,~ is supported by the fact timt tim cells lining the vascular spaces in o u r case stained with antibodies to factor VIII-associated antigen. This m a r k e r for endothelial cells, which normally elaborates some of the components to factor VIII, even in i n ' v i t r o
++ -'+++
+ Present.
c o n d i t i o n s , has b e e n s u c c e s s f u l l y used to i d e n t i f y endotheliunt-derived cells in tissue sectiolts3 T i m light and electron nticroscopic features in o u r cases o f histiocytoid h e m a n g i o m a were similar to those previottsly described and reviewed by Rosai et al.t; they include an increase in the n u m b e r of cytoplasmic organelles. Tim unique electron microscopic feature of these endothelial cells, however, is the abtmdance of cytoplasmic filaments. 6"r In respect to this feature, as well as to all the otlter morphologic features found, including a positive reaction for factor VII I-associated antigen, the endothelitnn in the vessels of the malignant schwannoma was identical to tlm vascular lining cells of the histiocytoid henmngiomas. T i m positive reaction of tlte lfistiocytoid endothelial cells for factor V I I I - a s s o c i a t e d a n t i g e n has not been previously reported. T h e significance of the a b t m d a n t cytoplasmic filaments in these cases is not known. Tim filaments appear instrumental in modifying cellular shape in that the endothelial cells "stand up" and orient their long axes perpendicular to the wall of tim vessel instead o f parallel to the direction of the blood flow. 7 Tim usual presence of cytoplasmic filaments in endothelial cells has been regarded by some authors, including Ma.ino et al.,s as evidence of botlt cellular smooth muscle differentiation and contractile capability. The small bundles of filaments are typically located in a perinuclear position when tim cell is at rest. When tim "contractile" endothelial cell described by Majno is seen in what is interpreted as the contracted state, it differs from tim histiocytoid endothelial cell. It protrudes into the vascular hlmen only in the plane o f section o f the n u c l e u s , the cytosol is p u s h e d into pseudopodia at the a b h u n i n a l surface, and organelles, including the few bundles of filaments, are gathered in the subuuclear space. T h e histiocytoid endothelial cell differs also from endothelial cells described in newly formed vessels of such angiomatous lesions as pyogenic g r a n u l o m a mainly by the near-absence o f filaments in the latter. 6 T i m significance of the centrioles that we regularly observed reinains unknown. T h e y have been described in endothelial cells of lymphatic channels but were not considered "markers" for that cell. s Ztte histogenesis of tbe histiocytoid lmmangiomas is not currently known. Similar endothelial cells are known to
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PATItOLOGY--VOLUME
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Febntary 1982
Figure 2. A, endothelial cells from the malignant schwannoma. The cells "stand up," projecting into tile ~ascular lumina. Whorls of cytoplasmic filaments are a d o m i n a n t feature. (Uranyl acetate-lead citrate stain, x20,000.) B, endothelial cells of tile malignant schwannoma show intrahnninal c)toplasmic projectious filled with coarse filaments, some o f which show lveriodic condensations (arrows). Intercellular junctions and a well-developed basement m e m b r a n e are seen. (Uranyl acetate-lead citrate stain, x32,000.)
176
CASE STUDIES exist in lymph.nodes t~ and liver, H and they have been found in a nmlignant schwannoma, in urticaria pigmentosa, v~ and in e x p e r i m e n t a l Iiyl~ertensionta----conditionsall known to produce vasoactive substances. These distinctive endothelial ceils occur, therefore, in very diverse clinical conditions. Whether the histiocytoid endothelial cells represent a proliferation of a subset of special endothelial cells tlmt are nornmlly present or the metabolic activation of "normal" endothelial cells by some vasoactive substances remains to be settled. T h e physiologic relevance of the morphologic observations and their relation to the genesis of the lesion may not become clear until an in vitro test system becomes available to study morphologic clmnges inducible in endothelial cells by vasoactive substances. In the meantime, the positive identification o f this special endothelial Cell may require electron microscopy in some lesions, because look-alike llorid endothelial cells scen by light microscopy may correspond to a different and, by electron microscopy, distinct constellation oforganelles. We agree with Rosai et al? tlmt the distinctive "histiocytoid endothelial cell" ma t, occur more commonly than was previously suspected.
REFERENCES I. Rosai J, Gohl J, Landy R: The histioc)toid hemangiomas, llum i'athol 10:107, 1979. 2. Sternberger LA, llardy PII Jr, Cuculis JJ, et ah The nnlaheled antibody.enzyme method of immunohistochemistry: preparation and properties of soluble antigen-antibody complex (horseradish peroxidase-antihorseradish peroxidase) and its use in identification of spirochetes. J llistochem 18:315, 1970. 3. Guccion JG, Enzinger FM: Malignant schwannoma associated with Von Rechlinghausen's neurofibromatosis. Virchows Arcb (l'athol Anat) 383:43, 1979. 4. WaggenerJD: Uhrastructure ofbenign peripheral nerve sheath tumors. Cancer 19:699, 1966. 5. Mukai K, Rosai J, Burgdorf WIIC: Localization of factor Vlll-related antigen in vascular endothelial cells using an immunnperoxidase method. Am J Surg Pathol 4:273, 1980. 6. Majno G, Jorls I: Endotbelium 1977: a review. Adv Exp Med Biol 104:169, 1978. 7. Thorgeirsson G, Robertson At.: The vascular endothelium: pathobiolo#c significance. Am J Pathol 93:803, 1978. 8. Majno G, Shea SM, Leventhal M: Endothelial contraction induced by histamine-type mediators. J Cell Biol 42:6-17, 1969. 9. Lauwcryns JM, Boussae WL: Striated filamentous bundles associated with centrioles in pulmonary lymphatic endothelial cells. J Uhrastruct Res 42:25, 1973. 10. Anderson ND, Anderson AO, Wyllie RG: Microvascular changes in lymph nodes draining skin allografts. Am J Pathol 81:i31, 1975. l 1. Johannessen JV: The Liver. In Johannessen JV (ed): Electron Microscopy in Iluman Medicine. McGraw-tlill Book Co., 1979, p 17. 12. Ludatscber RM: Ultrastructure of human dernml blood scssels with a special reference to the endothelial filaments. Virchows Arch (Cell Pathol) 27:347, 1978. 13. Still WJS, Dennisnn S: Tim arterial endothelium of the hypcrtensive rats. Arch Pathol Lab Med 97:337, 1974.
ACKNOWLEI)GMENTS We wish to thank Dr. Waher C. Bauer and Dr. Joseph R. Williamson for advice in the preparation of this m a n n script.
PELIOSlS OF THE SPLEEN WITH RUPTURE ROGI.:R L. GARCIA, MD,* MATIIFI:'N K. KIIAN, MD,t AND RICIIARD B. BFRLIN, MD:[:
A case ofpeliosis of the spleen without apparent involvement of the liver or other organs is presented. The peliosis was discovered following rupture of the spleen after minimal trauma and was successfully treated by surgery. None of the common associations of peliosis was present (i.e., tuberculosis or intake of steroM compounds). Drug add#tion and chronic alcoholism were the only coexisting debilitating conditions exhibited by this patient, llum Pathol 13:177-179, 1982. Peliosis of the spleen is an extremely rare entity that is virtually always associated with peliosis of the liver. Peliotic changes of these organs have been described in association witlt anabolic steroids, oral contraceptives, anti pulmotmry tuberculosis. We report here a patient with peliosis of the spleen who was totally asymptomatic and without any known associated factors other than drug addiction and chronic alcoholism. She presented with a r u p t u r e d spleen and intraperitoneal hemorrhage following minimal trauma and was treated successfully. CASE REPORT A 48-year-ohl wonmn was admitted through the emergency rootn with left-upper-quadrant abdominal pain. She had fallen while intoxicated three days earlier a n d had * Assistant Attending Pathologist 1 Resident in Pathology ~t Chief Resident in Surgery Received from the Department of Pathology and Surgery, Beth Israel Medical Center, New York, NY, and Mount Sinai School of Medicine of the City University of New York. Address correspondence and reprint requests to Dr. Garcia, Deparmaent of l'athology, Beth Israel Medical Center, 10 Nathan D. Perhnan Place, New York, NY 10003.
struck her left lower ribs. Radiographs sttowed no fractures. She denied nausea or vomiting. Her medical history revealed chronic alcoholism as well as drug addiction. She had used heroin in tile past and had later received m e t h a d o n e as part o f a detoxification plan. Both of her parents died of tuberculosis, ahhot,glt she had never been treated for it and had no stigmata of the disease. T h e patient did not take any medications and had not taken steroids. She was, at this time, four years postmenopavsal and had never taken oral contraceptives. She had one normal child. Physical e x a m i n a t i o n revealed a n o r m a l - a p p e a r i n g heahhy woman. Her blood pressure was 100 m m Hg systolic and her pulse rate 100 beats/min. Her a b d o m e n was soft and not tender; there was no guarding, and bowel sounds were present. Serum amylase was normal, alkaline phosphatase 69 U/l, bilirubin 0.2 mg/dl, and SGPT 22 U/I. l'araceutesis was p e r f o r m e d , and gross blood r e t u r n e d . q'he patient's hematocrit was 29 per cent. An emergency laparotomy revealed a r u p t u r e d spleen with some fibrous adhesions between its capsule and the abdominal wall. T h e spleen was removed without diffictflty; during surgery the liver and pelvic organs were carefully examined for signs of trauma or hemorrhage a n d were fotmd to be completely u n r e m a r k a b l e on their external surfaces. T h e patient's postoperative course was without complication. When the pathologic examination of the removed spleen revealed the existence of peliosis, an extensive evahmtion of 9the patient was carricd out. It included a hepatic arteriogratn, C A T scan, tipper gastrointestinal series and barium enema studies, and intravenous pyelogratn; serum cortisol and testosterone as well as 17-hydroxy-corticosteroids and 17-ketosteroids in 24-hour urines were also evaluated. All these studies failed to reveal any other significant pathol-
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