ELASTOFIBROMA. J. ROBIN BARR, M.B., CH.B. Department of Pathology, Ottawa Civic Hospital, Ottawa, Ontario, Canada REPORT OF CASES

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1 THE AMERICAN JOUHNAL oi' CLINICAL PATHOLOGY Copyright 1966 by The Williams & Wilkins Co. Vol. 45, No. 6 Printed in U.S.A. ELASTOFIBROMA J. ROBIN BARR, M.B., CH.B. Department of Pathology, Ottawa Civic Hospital, Ottawa, Ontario, Canada Jarvi and Saxon, 4 2 Finnish workers, in 1961 reported a previously undescribed benign connective tissue tumor in 4 elderly individuals. Because of its apparent constant situation and microscopic appearance, they called it elastohbroma dorsi. The lesion, which was situated in the lower subscapular region underneath the rhomboid and latissimus dorsi muscle, was often fixed to ribs or intercostal ligaments, and in all but the 1 case was unilateral. To date, no recurrences have been reported. Since then, only 3 additional cases have been reported 1 ' 8 although Dr. Arthur Purdy Stout 9 has personally seen 4 additional ones. These graywhite tumors ranging in size from 5 to 9 cm. in diameter and 2 to 3 cm. in thickness were nonencapsulated and ill-defined, cut with difficulty, and appeared grossly to be composed of small lobulated areas of fatty tissue separated by dense bands of fibrous stroma. Microscopy revealed them to be composed of broad bands of rather acellular fibrous connective tissues separated by lobules of mature fat. No bizarre cells or mitotic figures were observed. The striking feature was the presence of numerous, irregular, branching, slightly eosinophilic fibers, and scattered granules and globular structures with similar staining characteristics. The fibers were of several types. They ranged in thickness from 1 to 30 M- Many followed the plane of the collagenous fibers, whereas others were arranged transversely or haphazardly. Some were single, whereas others were arranged in clusters or tangles; many had a fairly uniform diameter whereas others varied considerably; others were extremely nodular. Both the fibers and the granules exhibited a striking affinity for elastic stain. The first of these 3 cases to be reported is the only 1 to date with bilateral asynchronous tumors. The third case is of interest because it did not occur immediately below the scapula but was situated over the greater trochanter of the femur. Received, December 10, REPORT OF CASES Case 1. This 45-year-old Caucasian Canadian female audit clerk of European extraction first presented in February 1960, complaining of discomfort and a sensation of fullness of 1 year's duration below the inferior margin of her right scapula. Physical examination revealed the presence of an illdefined firm tumor, 10 cm. in diameter, situated below the inferior angle of the right scapula. At operation, its margins could not be accurately defined and it was removed with some difficulty by sharp dissection. The specimen, which measured 5 by 7 by 1.5 cm., was gray-white and firm. Cross section revealed widely scattered yellow fatty areas separated by broad lines of white "fibrous tissue." The histologic diagnosis at that time (February 10, 1960) was lipoma (Figs. 1 and 2). The patient next presented in May 1964, complaining of a similar lesion of 1 year's duration situated below her left scapula. On this occasion, the specimen, weighing 65 Gm., measured 7.5 cm. in maximal transverse diameter and 2 cm. in thickness. It was yellow-white and firm, with an adherent portion of muscle. Cross-section revealed numerous small islands of fatty tissue separated by gray-white fibrous bands (Fig. 3). Microscopic examination revealed the presence of the irregular fibers and granules typical of elastofibroma dorsi as described by previous authors. In view of the patient's history, the sections of the lesion removed in 1960 were reviewed and this also was obviously an example of elastofibroma dorsi. When the patient was examined in September 1965, there were no signs of recurrence on either side. Case 2. Mrs. A. L., aged 62, presented in July 1964, with a lump of 3 months' duration under the wing of the right scapula. A somewhat discrete nonencapsulated tumor, 8 by 5.5 by 3 cm., was removed from below the right rhomboid. It was light brown to white, and rubbery. Microscopy revealed

2 680 BAHR Vol. 45 an appearance now recognized as typical of elastofibroma dorsi (Figs. 4 and 5). When the patient was re-examined in June 1965, there were no signs of recurrence. DISCUSSION In view of the suggested hypothesis that this tumor might result from friction of the scapula over the rib cage, it was decided to study the infrascapular area in older individuals. Material was removed from this site in 25 persons over the age of 65, together with a sample of skin and subcutaneous tissue from the anterior aspect of the thigh, and these were all stained for elastic tissue with A r erhoeff stain. This revealed 2 types of fibers (Figs. 6 and 7). One was slender and sometimes branching, whereas the other was thick, short, and often segmented. All of these fibers had sharp edges and none exhibited a globular degenerative change in any area. In the few sites where tangles or knots existed, it was easy to distinguish individual, sharply demarcated fibers. An additional microscopic feature which distinguished the elastic tissue in these biopsies from "elastic tissue" in the tumor was the fact that it had a different tinctorial characteristic, having a purple tint. In order to explore any possible link with the fibromatoses, 20 cases of plantar fibromatosis and 1 case of palmar fibromatosis from the files of the Ottawa Civic Hospital from 1963 to 1965 were reviewed. These lesions were stained with hematoxylin-phloxin-safranine and Verhoeff's elastic stain. The elastic fibers present were chiefly broad, with clear-cut edges, and no globular or granular forms were observed. Re-examination of material from tumors failed to reveal any normal-appearing elastic fibers, either of a thin or thick variety, with sharp edges. All had fuzzy or globular margins and there wei - e numerous globular masses. Reticulum stains revealed the presence of fine reticulum fibers in some of these masses. In a further endeavor to discover the pathogensis of this unusual tumor and its connection, if any, with other soft tissue fibrous lesions, it was also decided to examine all available lesions from the soft tissues of the trunk. It was during the course of this study that the third case was discovered. Case 3. Mr. L. E., a 75-year-old Caucasian Canadian man, presented with an ill-defined, rubbery to firm, partially mobile lump, of 1 year's duration, situated over the greater trochanter of his left femur. The mass had been gradually increasing in size. He could remember no definite trauma to the region. The preoperative diagnosis was possible fibrosarcoma of the thigh. The surgical specimen weighed 20 Gm. and measured 8 by 5 by 3 cm. Cross-section revealed it to be comprised of white fibrous tissue with a few small islands of fat. Microscopy revealed the presence of a slitlike space, lined by mesothelial cells, resembling a bursa (Figs. 8 to 10). This was surrounded by dense fibrocollagenous tissue, throughout which were scattered small nests of mature adult fat cells. A closer perusal of the collagenous tissue revealed that, in many areas, it was somewhat smudgy and slightly more eosinophilic in hue, with small globular and elongated, slightly nodular structures. In view of this, the material was stained with Verhoeff's stain for elastic tissue. This revealed the smudgy nodular areas and fibers to be identical to those previously reported in the elastofibroma dorsi lesions. Examination of bursas removed from both the lower and upper limbs, however, did not reveal any similar changes. It thus appears likely that the fibers, although they stain with some of the elastic tissue stains, should, as Dr. Stout and others believe, be called elastotic rather than elastic. The development of these fibers is still disputed. 2, 3 ' 6_8 ' 10 Some authors postulate an origin from pre-existing elastic tissue, whereas others believe that they may arise from collagen which has been traumatized, with subsequent reticulum fiber deposition and accumulation of elastotic material. The amount of positive-staining material is certainly far in excess of elastic tissue normally found in these areas. This study and the findings of the third case indicate that the lesion is not a normal aging process, and that it can not be classed as a fibromatosis, but that it results from elastotic degeneration of collagen following trauma and friction in individuals who possibly have some inherent enzymatic defect related to connective tissue metabolism.

3 '4 '... or '"' *. FIG. 1 (upper left). Case 1, February Typical appearance of tumor from right side, showing broad bands of dense collagen with smudgy globular masses and fibers. Hematoxvlin-phloxin-safranine. X 300. FIG. 2 (upper right). Similar to Figure 1, illustrating thick fibers and globular masses. Verhoeff. X 300 FIG. 3 (lower left). Case 1, May Lesion on left side, showing globular masses. Verhoeff. X 300 FIG. 4 (lower right). Tumor in Case 2, showing typical pattern. Hematoxylin-phloxin-safranine. X

4 F I G. 5 (upper left). Section from Case 2 stained to show elastic fibers. Verhoeff. X 300 F I G. 6 (upper right). Tissue from infrascapular region in a 76-year-old man, showing thin and thick fibers with sharp margins and tangles. Verhoeff. X 500..,,, F I G. 7 (lower left). Tissue from infrascapular region in 68-year-old woman, showing thin and thick fibers of shorter type, b u t all with sharp edges and no globular forms or nodular masses. VerhoelT. F I G. 8 (lower right). Sections from Case 3, showing bursa with mesothelial lining. Hematoxylinphloxin-safranine. X

5 June 1966 ELASTOFIBROMA C83 \ r, \!.v ' :* ;'.// ' M. > ". :. v." ' <v. V '.%. ; H- W;V:-".:». Fia. 9 (left). Section from Case 3 showing irregular fibers and globular masses embedded in broad bands of fibrooollagenous tissue separated by islands of fatty tissue. VerhoefT. X 50. FIG. 10 (right). Simihir area from Case 3, with high magnification to show globular masses. VerhoefT. X"100. SUMMARY Three cases of elastofibroma, 1 with asynchronous bilateral dorsal lesions, are reported. The occurrence of the third lesion over the greater trochanter, associated with a bursa, suggests that repeated trauma or friction may play a role in this condition. It is thought that this lesion is not truly neoplastic and that it should be known as "elastofibroma" rather than "elastofibroma dorsi," on account of the discovery of a similar lesion situated over the greater trochanter of the femur. Acknowledgments. Dr. M. 0. Klotz, Chief, Department of Pathology, Ottawa Civic Hospital, gave advice during preparation of this manuscript. Dr..1. C. Samis gave permission to publish Case 1; the Canadian Tumour 'Registry and Dr. E. L. Barton gave permission to publish Case 2; and Dr. P. Capello permitted us to publish Case 3. Mr. F. M. Smith, Department of Photography, Ottawa Civic Hospital, prepared the photomicrographs. REFERENCES Delvaux, T. C, and Lester, J. P.: Elastofibroma dorsi. Am. J. Clin. Path., 48: 72-74, 19G5. Findlay, G. H.: On elastase and the elastic dystrophies of the skin. Brit. J. Dermal., 66: 16-24, Gillman, T., Perm, J., Bronks, D., and Roux, M.: Abnormal elastic fibers. A. M. A. Arch. Path., 59: , Jarvi, O., and Saxen, E.: Elastofibroma dorsi. Acta path. & microbiol. scandinav., Si (Suppl. 144): 83-84, Keech, M. K., and Reed, R.: Enzymatic elucidation of the relationship between collagen and elastin. Ann. Rheumat. Dis., 16: 35-62, Moran, T. J., and Lansing, A. T.: Studies on the nature of the abnormal fibers of pseudoxanthoma elasticum. A. M. A. Arch. Path., 65: , Pearse, A. G. E.: Histochemistry. Boston: Little, Brown & Company, Stemmermann, G. N., and Stout, A. P.: Elastofibroma dorsi. Am. J. Clin. Path., 37: , Stout, A. P.: Personal communication, Walford, R. L., Mover, D. L., and Schneider, R. B.: The structure of elastin. Arch. Path., 72: , 1901.