UNDIFFERENTIATED ROUND-CELL OF THE ILIUM (EWING TUMOR) CONTAINING HEMOPOIETIC ELEMENTS

N. W. ROOME, M.D., AND P. A. DELANEY, Pu.D., M.D. (Prom the Departments of Surgerg and Pathology of the Universily oJ Chicago) The undifferentiated round-cell sarcomata of grouped together by Ewing (I) in 1922 as "diffuse endothelioma" are con- sidered an oncological entity by most authors. Considerable doubt exists, however, as to the origin of the Ewing sarcoma. Ewing and his supporters believe that it is derived from an endothelial cell of the bone marrow, possibly the perivascular lymphatic endothe- lium, and now apply the name "endothelial myeloma'' with that significance. Kolodny (2), Oberling (3), and others think that these tumors may arise from the reticulum cells or the reticulo- endothelium. Certain facts suggest a relation to the myelomata: multiple tumors frequently appear early in the disease, there is usually regression under radiotherapy, and the structure may "verge on myelomau( Ewing, I). Connor (4) and Kolodny (2) mention that in a small percentage of cases some myeloid and plasma cells are to be found in the tumor tissue, though neither author describes the method of identification of these cells, nor their relation to the neoplastic cells. In the case to be reported, there was a large primary tumor of the ilium, with skeletal metastases almost completely replacing the bone marrow, and little visceral involvement. These are unusual features for a Ewing sarcoma, but other evidence leads to that diagnosis. Upon the application of special staining methods, there was found scattered among the tumor cells an admixture of differentiated cells, apparently members of the hemopoietic series; and a proportion of the "undifferentiated" tumor cells seemed to resemble the myeloid stem-cell, the hemocytoblast. The possible significance of these findings will be discussed later in this paper. CASE REPORT R. C., a white male, aged nineteen years, entered the University of Chicago Clinics Aug. 9, 1928, complaining of (1) pain in the lower ex- tremities, especially the left, (2) a swelling in the region of the left ilium,

1 This work was done under a grant from the Douglas Smith Foundation for Medical Research. 386 UNDIFFERENTIATED ROUND CELL SARCOMA 387

(3) loss of vision in the right eye, and (4) gradual loss of weight and strength. Two years before admission he began to have transient sharp pains in the left hip region and down the back and outer side of the left leg, which were worse at night and gradually increased in severity. For the past ten months he had had a dull ache in his back, and fleeting pains in the right leg, back, shoulders, and face. Four months before admission he had suddenly lost most of the vision in the right eye, following a severe headache; and a little later he had developed a partial anesthesia of the right side of the face, which slowly disappeared. During the past six months he had gradually become pale, and had lost weight and strength. Tonsillectomy was done six months before admission because of x-ray findings of some disease of the left ilium. Three months before admission a mass was first palpated in that region; two exploratory operations were performed, leading to the diagnosis of osteomyelitis, though the wounds healed per primam, and no relief was obtained. The left leg had been weak for several months, and because of pain and general weakness the pat,ient had been confined to bed since the operations. Physical examination on admission disclosed a pale, weak, emaciated young man, suffering considerable pain. The right eye protruded slightly, and was nearly blind; the left eye showed a contraction of the visual field. The left pupil was the larger; both pupils reacted to light. There was a marked primary optic atrophy of the right eye; the other cranial nerves were objectively normal. No nodules were palpable on the skull, and the cervical lymph nodes were not enlarged. The lung areas were normal, as was the heart except for a soft, non-transmitted, systolic murmur at the apex. The abdomen was normal, except for a fulness of the left lower quadrant, where there was a firm, non-tender mass about the left ilium, filling out the iliac fossa, and laterally resulting in a moderate swelling of the gluteal region. On rectal examination the lower portion of this mass was palpable, filling out the left side of the pelvis; the prostate and seminal vesicles were normal. There were healed scars of operative incisions along the crest of the ilium, and just above the inguinal ligament. The left inguinal lymph nodes were moderately enlarged, firm, and slightly tender; nowhere else in the body were en- larged nodes detected. The muscles of the left leg were paretic, and mo- tion of the hip joint was painful and limited, but there was no sensory disturbance. Palpation of the entire skeleton revealed no other enlarge- ments nor areas of tenderness. The reflexes were normal except for a diminution of the left abdominal and left cremasteric responses. The white blood count was 19,000; the red blood count was 3,000,000, and the hemoglobin 60 per cent (Tallquist). The urine was repeatedly normal; no Bence-Jones protein was discovered. Blood Wassermann and Kahn tests were negative. Roentgenograms disclosed an increased thickness and density of the greater part of the left ilium and adjacent parts of the ischium and pubis. There was evidence of new bone formation on both surfaces of the ilium, appearing laminated on the outer surface, and more irregular 388 N. W. ROOME AND P. A. DELANEY and fuzzy on the inner surface (Fig. 1). No other lesions could be found at the first x-ray examination of the remainder of the pelvis, lumbar spine and sacrum, both femurs, chest, and skull. A tentative diagnosis of Ewing tumor of the ilium, with metastases in the region of the optic chiasm, was made. A series of 31 injections of Coley's toxin was given from Aug. 13 to

Oct. 20, 1928, in doses increasing from 0.01 C.C.to 1.2 c.c., with febrile reactions after each, of 103" to 104.4' F. X-ray therapy was begun Aug. 30, 1928, a total of 600 Roentgen units being given, half anteriorly and half posteriorly, centered on the left ilium; a shorter course was also given over the right and left temporal regions, centered on the optic chiasm. Following this therapy the patient felt better. He had less pain and more function in the legs, and the mass in the pelvis decreased slightly in size. The x-ray findings remained almost unchanged. The eyes gradually UNDIFFERENTIATED ROUND CELL SARCOMA 389 became more prominent, and in October the patient complained of numb- ness of the left buccal mucous membrane. On Nov. 4, 1928, an oval tumor about 1.5 X 2.0 cm. was discovered on the right clavicle approximately 3 cm. from its sternal end; a roentgeno- gram showed at the corresponding point evidence of slight periosteal new bone formation with irregular reduction of the bone density beneath. A biopsy was done and a soft grayish tumor was found, which had eroded the bone and projected beyond its surface. Microscopic examination showed it to be made up of masses of closely packed round cells, with oval vesicular nuclei containing scattered finely granular chromatin, and non-staining cytoplasm; there were occasional mitotic figures (Fig. 2). The diagnosis of undifferentiated round-cell sarcoma (Ewing tumor) was thus confirmed.

FIG. 2. TISSUEOBTAINED BY BIOPSYOF THE RIGHTCLAVICLE, NOV. 1928. X 835 X-ray studies in November and December showed small scattered areas of reduced density in cortex and medulla of both humeri, femora, tibiae and fibulae, and some periosteal new bone formation in the upper thirds of the humeri; there were no changes in the of the forearm and hand. There was irregular reduction of density of the sacrum and right and left pubic and ischial bones. The appearance of the left ilium was little altered. The humeri, right clavicle, and right pelvis were given short courses of x-ray therapy. The red blood count, Nov. 7, was 2,800,000. After December the condition became progressively worse; t,he mass in the pelvis enlarged and there were at times increasingly severe pains throughout the body. In January 1929 the patient suffered minor accidental burns of the abdomen, chest, and hands, which healed slowly. A differential white blood count on Jan. 25 showed 74 per cent polymor- phonuclear leukocytes, 3 per cent large lymphocytes, and 23 per cent small lymphocytes; no abnormal cells were described in the smears. 390 N. W. ROOME AND P. A. DELANEY

Edema of the feet and ankles appeared in February and progressed to an extreme degree on the left side; in March the abdomen became distended, and free fluid and rhles were found in the chest. In April decline was even more rapid; on April 9 the white blood count was 8,600, the red blood count 1,260,000, and the hemoglobin 30 per cent. Palpable metastatic nodules appeared on the skull. The patient became incontinent and comatose, and died April 22, 1929. Throughout the illness the mouth temperature had fluctuated irregularly between 98" and 101" F. Necropsy Findings: Necropsy was done about two hol~rsafter death, by Dr. H. G. Wells. The body was extremely emaciated; there was little subcutaneous or omental fat. The mucous membranes, skin, muscles, and viscera were very pale; the skeletal muscles were atrophic. There was moderate edema of the lower extremities. A small amount of clear watery fluid was found in the abdominal cavity and there were a few fibrinous adhesions. The liver, gallbladder, stom- ach, esophagus, and bowel were grossly normal. In about the middle of the pancreas was a firm nodule 1.2 X 1.2 X 1.5 cm., creamy white, and of brain-like texture on section. The spleen was somewhat enlarged, weighing 200 gm.; externally it was purplish brown, with a few small creamy white areas, the largest being 0.4 cm. in diameter and extending 0.3 cm. into the tissue. The cut surface of the spleen was reddish brown and displayed no visible nodules. The adrenal glands were alike, and their cortical lipoid substance appeared diminished. The left ilium, pubis, and most of the ischium were surrounded by a tumor mass (Fig. 3) which filled the pelvic cavity to the midline, was 1.0 to 4.0 cm. thick on the outer surface of the ilium, and extended from the 4th lumbar vertebra above to the ischial tuberosity below. It was moderately firm, coarsely nodular, and covered by a pseudocapsule of pelvic fascia on its mesial surface, and by the gluteal muscles laterally. The iliac lymph nodes were enlarged as much as 2 X 2 X 1.5 cm. and on section appeared markedly infiltrated by creamy-white, brain-like tissue; the iliac vein was filled with a core of similar tissue. The head of the femur was surrounded above by tumor and was only slightly movable; on the anterior surface of the femur at the level of the lesser trochanter there was a subperiosteal tumor nodule 3 X 2 X 1 cm. Upon incision of the mass sagittally, 6 cm, from the midline, the ilium was seen dense and thickened, varying from 1.5 to 3.0 cm. in thickness. The surrounding mass was coarsely trabeculated and varied in consistency in different areas from moderately soft to quite firm; it nowhere contained bone or . It, was of brain-like texture, and grayish to creamy-white in color, wit,h small irregular areas of yellow pigment, old hemorrhage, and necrosis. The cut surfaces of all the lower lumbar and sacral vertebrae showed a massive infiltration with tumor similar to that to be described in the other bones. The lungs were small and collapsed, the right and left pleural cavities containing 300 and 1900 C.C. respectively of clear fluid. Both pleural surfaces were studded with many small, firm, smooth gray nodules, the largest being 0.7 cm. in diameter and only slightly raised; these were locnt,ed especially along the course of the pleural lymphatics and along UNDIFFERENTIATED ROUND CELL SARCOMA 391 the lung margins, where they formed nearly continuous ridges. No nodules could be found in the substance of the lung. The tracheo- bronchial lymph nodes were enlarged, in part caseous and in part firm, and slightly calcified.

FIG. 3. ILIAC TUMOR,A8 REMOVEDAT NECROPBY Note the involvement of the sacrum, and the nodule (arrow) on the surface of the femur.

The pericardium contained 100 C.C. of clear fluid and was otherwise normal. The heart showed a patent foramen ovale 1.0 cm. in diameter, guarded by a fold of endocardium; and there was a moderate tricuspid dilatat,ion. The myocardium was pale brown in color. The aorta and great vessels were normal. The thyroid was pale but otherwise normal; the thymus was atrophic but recognizable and weighed 5.5 gms. 3 92 N. W. ROOME AND P. A. DELANEY

The kidneys were pale and their cortex swollen. The urinary bladder was thickened and contained small mucosal hemorrhages. The prostate and seminal vesicles were normal, the testicles undeveloped. Upon removing the calvarium, the tabula interna was found exten- sively infiltrated and eroded by soft, partly necrotic tumor; the tabula ex- terna exhibited several such areas. The erosion of the inner surface extended into the occipital bone, the right and left frontals, thence to the base of the skull and the sphenoid, of which the right wing was especially involved. The lateral walls of both orbits were invaded, the right more extensively than the left. The hypophysis and pineal gland were normal. The dura mater was invaded by an overgrowth of tumor from the skull; it was densely adherent to the calvarium and on removal was found covered in about one-half of its outer surface by irregular masses of tumor tissue, which penetrated through in places and appeared on the inner surface as smooth, flattened nodules as large as 2.0 cm. in diameter. These were not adherent to the pia arachnoid, and had produced small areas of super- ficial brain atrophy. The falx cerebri presented none of these nodules, and no special mass of tumor was found in the region of the optic chiasm except as already described on the floor of the anterior fossa. The following bones were removed from the body in addition to those adjacent to the pelvic tumor: two and one half lumbar vertebrae, two ribs, the right clavicle, the left femur, patella, tibia, and fibula. Of these, all showed the same type of involvement, varying somewhat in degree; and it may be assumed that the remainder of the skeleton would have shown similar changes. The femur was most involved (Fig. 4). The periosteum was rough- ened and thickened; under it were flat irregular nodules of soft creamy tissue, as large as 0.3 X 2.0 X 4.0 cm., which occurred especially towards the ends of the shaft, where they were confluent. On section, the can- cellous bone and the were entirely filled with tumor of soft and friable texture, extensively necrotic, and containing multiple small areas of hemorrhage and liquefaction. The epiphyses were exten- sively invaded. The cortex was thinned, and irregularly eroded by soft tissue from the medulla; the outermost layers were relatively compact, but extensively penetrated at the seats of the subperiosteal nodules. The changes in the other bones were similar to those in the femur ex- cept for certain particulars. In the tibia and fibula there was less cortical invasion and correspondingly less subperiosteal growth, though at the extreme ends of the bone nearly all the surface was eroded, and there was a large nodule at the upper end of the tibia. The clavicle, which had re- ceived considerable irradiation, was sclerotic throughout, and the sur- rounding tissues fibrosed; there was only moderate medullary involve- ment and a few small nodules on the surface. From the ribs the tumor had extended to the pleura, appearing on its inner surface as the small nodules already described. There was extensive infiltration of the cancel- lous spaces of the vertebrae with occasional penetration of the cortex, resulting in nodules as large as 3.0 X 2.5 X 1.5 cm. on the surface of the bodies of the vertebrae. There was also noted a rupture of the articular UNDIFFERENTIATED ROUND CELL SARCOMA 393 cartilage of the fourth lumbar vertebra, with expansion of the nucleus pulposus into the body of the vertebra ("Schmorl's (5) disease") with scanty surrounding sclerosis. Microscopic Findings: The large iliac tumor was fixed in Kaiserling's solution; blocks were cut from several different areas, washed, re-fixed in formol-Zenker solution, and stained with hematoxylin-eosin, and

with Maximow's (6) hematoxylin eosin-azur 11. The microscopic ap- pearance of the tumor varied considerably throughout its mass, most of it showing degeneration, necrosis, and occasional hemorrhage. The tissue contained a moderate number of blood vessels in the more viable regions and was made up of small round and polyhedral cells, lying free in masses and separated by non-tumorous connective-tissue septa. There was no 394 N. W. ROOME AND P. A. DELANEY tendency towards a perithelial arrangement, nor to the formation of walls of vascular spaces. Mitotic figures were infrequently seen. Most of the cells were similar to the type cell of the Ewing sarcoma; they had a mod- erate amount of non-granular basophilic cytoplasm, a rounded vesicular nucleus with irregularly scattered granular chromatin, and one to three acidophilic nucleoli. There was considerable variation in cytology, and certain cells (comprising about 10 per cent of the total number) seemed to resemble the free basophil stem-cell of the hemopoietic series, the hemo- cytoblast, though few could be said to be as typical as the examples seen in normal marrow (Fig. 5). A small proportion of cells, mostly towards the periphery of the tumor mass, were seen to contain in their cytoplasm neutrophilic (and in a few cells, eosinophilic) granules, identifying them

rather positively as myelocytes and premyelocytes; these were seen in various stages of maturation, and occurred in groups surrounded by and apparently intimately related to the less differentiated cells (Fig. 6). Most positively identified were several megakaryocytes, huge cells of irregular outline, with characteristic irregular lobulated nucleus; these also presented various stages of maturation (Fig. 5). Certain cells were seen with a relatively smaller and more compact nucleus, and non-granular acidophilic cytoplasm; these may possibly represent normoblastic types, but are difficult to differentiate from pyknotic degeneration of other cells (because of the fixative used). Sections of the bony portions showed dense trabeculae, with cancellous spaces filled with degenerated tumor cells; no normal bone marrow was found. The adjacent iliac lymph nodes were densely filled with tumor cells, nearly obliterating their norm81 structure. The occluded iliac vein was UNDIFFERENTIATED ROUND CELL SARCOMA 395 found filled with an organizing thrombus which contained a small island of tumor cells near its center. In the other bones the marrow was almost completely replaced by metastases composed of cells similar to those of the iliac tumor but with less pleomorphism. The Haversian systems were irregularly invaded and expanded, with slight erosion of the bone produced by the tumor cells without the aid of giant cells. Small scattered areas of fatty, normal, and fibrous marrow were seen at various points. There were occasional areas of reactive new bone formation, and in certain locations a consider- able sheet of subperiosteal new bone, but no evidence of actual tumor bone or cartilage. The tumor tissue in the pancreas was irregularly lobulated, separated

by strands of white fibrous . It was densely cellular and contained in certain areas small groups of pancreatic acini. Most of the tumor cells resembled the predominating cells of the iliac tumor; there were a few small islands of cells resembling erythroblasts and normo- blasts. The spleen contained a multitude of minute clumps of tumor cells in its sinuses, occurring mostly near the periphery of the organ, and with little tendency to invade the pulp. A few myelocytes and normo- blasts were identifiable in these tumor clumps; there was nothing to indicate whether these developed from the tumor cells or merely developed near them from non-neoplastic immature blood cells. The splenic pulp was increased, contained much brown pigment, and showed evidence of considerable myelopoiesis; there were several small peripheral anemic infarcts. The liver showed slight or no evidence of hemopoiesis, and there was no tumor seen in the organ. The kidneys contained a few very minute clumps of tumor cells in capillary blood vessels. Several sections of lung parenchyma showed no tumor growth, and no 396 N. W. ROOME AND P. A. DELANEY tumor cells in the blood channels; there was marked atelectasis, but no inflammatory changes, and much brown pigment in fixed and free "heart- failure" cells. The pleura was thickened and irregularly infiltrated by groups of tumor cells which occasionally extended very slightly into the lung tissue. Small clumps of tumor cells were found in the pleural fluid, which may explain the method of spread to the visceral pleura. The peribronchial lymph nodes were found moderately infiltrated with tumor. The dura mater showed a dense irregular infiltration by tumor, much of which was contained in blood vessels; there were a few myeloid cells seen scattered among the mass of undifferentiated cells. The other visceral tissues showed no tumor invasion. The gall-blad- der, stomach, esophagus, bowel, prostate, testicles, adrenals, and thyroid gland were essentially normal. The heart showed evidences of myo- cardial degeneration. The skeletal muscles were extremely atrophic, with hyalinization of the remaining fibers. The eyes, serially sectioned, showed no tumor invasion, but a toxic endothelial proliferation as de- scribed by Salzmann (7), springing from the arachnoid sheath of the right optic nerve. COMMENT The tumor reported is best considered an unusual type of Ewing sarcoma. The onset, the clinical course, and the x-ray appearance of the primary tumor are characteristic; the exception- ally large iliac tumor and the great extent and distribution of the metastases are very unusual features. Microscopically, by the routine staining methods, the findings are entirely compatible with this diagnosis. It is obviously impossible to think of the tumor as an undiffer- entiated osteogenic sarcoma; and it is unlike myeloma in several features, vix: (1) tendency to new bone formation in the original tumor (before radiotherapy); (2) the absence of sharply defined bone destruction in the metastases, giving an x-ray appearance in the extremity bones altogether unlike the punched-out areas of myeloma; (3) the absence of any tendency to skeletal collapse (pathological fracture); (4) the formation of a large isolated pri- mary tumor long before occurred; (5) the age of the patient, myelomata being quite rare under the age of thirty (Coley, 8) It is interesting to consider the character and significance of the differentiated cells found in the tumor.2 The granular cells are certainly myelocytes, and there seems no reasonable doubt con- cerning the megakaryocytes. The identification of the normo-

2 Our opinion as to the character of the differentiated cells in this tumor was con- firmed by Dr. Wm. Bloom of the Department of Anatomy, University of Chicago. UNDIFFERENTIATED ROUND CELL SARCOMA 397 blastic types is somewhat obscured by the fixation of the large mass of tissue in Kaiserling's solution and two hours post-mortem. It is difficult to say, therefore, whether the differentiated cells represent a reaction to the tumor, or are hemopoietic; and if the latter, whether they are differentiated from the tumor cells or from cells carried out from the original marrow. There is, however, considerable evidence in favor of the opinion that they represent hemopoiesis, and since it is unusual to find so far removed from bone as at the periphery of this large tumor, it is thought that the tumor may possibly be a myeloid stem-cell tumor, a hemocytoblastoma. Ewing (1) seems to believe that the "endothelial myeloma" is of endothelial origin, and has potentialities of development towards either angio-endothelium or hemopoietic tissue. The tumor re- ported in this paper may represent a borderline tumor, consider- ably differentiated towards the myelomata. We are not, however, convinced of the endothelial origin of the Ewing sarcoma, and be- lieve that further study of such tumors with Romanowsky-type stains may shed interesting light on the problem of their origin. We have applied Maximow's technic to a group of tumors diag- nosed Ewing's sarcoma by a majority of observers (obtained through the courtesy of the Registry of the Ameri- can College of Surgeons) ; none of these seemed exactly similar to the present case, there being a considerable variation in their cy- tology, and in none were any hemopoietic elements found. Case 385 most nearly approaches the picture of extreme skeletal in- volvement seen in the case reported here, and also presents a some- what similar histology, but no tissue was obtained for special staining. (Photographs of material from this case are included in Kolodny's report, 2 .) SUMMARY A case of round-cell sarcoma of the ilium, with extensive skeletal and few visceral metastases is described. It is classified as an atypical Ewing sarcoma. Special stains show the presence of hemopoietic elements in the tumor. The possibility that the tumor is a borderline Ewing sarcoma, merging into a myeloid stem-cell tumor (hemocytoblastoma), is discussed. 398 N. W. ROOME AND P. A. DELANEY

1. EWING,J.: Review and classification of bone , Arch. Surg. 4: 485-533, 1922. 2. KOLODNY,A.: Bone sarcomas, Surg. Gynec. & Obst., 1st suppl., 126- 154, 1927. 3. OBERLING,C. : Les rkticulosarcomes et les rkticuloendothkliosarcomes de la moelle osseuse (sarcomes d7Ewing), Bull. de 1'Assoc. frang. l'ktude du cancer 17: 259-296, 1928. 4. CONNOR,C. L.: Endothelial myeloma, Ewing, Arch. Surg. 12: 789-829, 1926. 5. SCHMORL,G., Die pathologische Anatomie der Wirbelsaule, Verhandl. d. deutsch. orthop. Gesellsch. 21: 3, 1927. 6. MAXIMOW,A,: Uber zweckmassige Methoden fiir cytologische und histogenetische Untersuchungen, Ztschr. f. wiss. Mikr. 26: 177-190, 1909. 7. SALZMANN,M. : Anatomy and Histology of the Human Eyeball, Eng- lish translation by E. V. L. Brown, Chicago, 1912, p. 101. 8. COLEY,W. B. : , Ann. Surg. 93: 77-89, 1931.