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Primary Leiomyosarcoma of Renal Capsule
0022-534 7/85/1335-0834$02.00/0 THE JOURNAL OF UROLOGY
Vol. 133, May
Copyright © 1985 by The Williams & Wilkins Co.
Printed in U.S.A.
Case Reports PRIMARY LEIOMYOSARCOMA OF RENAL CAPSULE W. D. NG, K. W. CHAN
AND
Y. T. CHAN
From the Surgical "B" Unit and Clinical Patlwlogy Institute, Princess Margaret Hospital, Kowloon, Hong Kong
ABSTRACT
The renal capsule long has been suggested to be the origin of leiomyosarcoma of the kidney but this speculation has never been proved. We describ~ a case of leiomyosarcoma lying within the renal capsule. The radiographic, as well as the macroscopic and microscopic appearances provide convincing evidence of capsular origin. Primary leiomyosarcoma of the kidney is a rare neoplasm. To date, approximately 90 cases have been described in the literature. Well documented cases of leiomyosarcoma of the renal capsule, if any, are much rarer. We report a case of leiomyosarcoma of the kidney capsule that presented distinctive morpholo°gical and radiographic features, making it the most well substantiated case. CASE REPORT
A 37-year-old man was hospitalized with a 1-month history of dull, aching right loin pain. He also became aware of an expanding lump in the right side of the abdomen. There was no history of hematuria or other urinary symptoms. Weight loss was 5 kg. during the same period. Physical examination was unremarkable except for a ballotable mass in the right flank, which was smooth and slightly tender. An abdominal x-ray revealed a soft tissue shadow in the right upper quadrant, which was confirmed later by ultrasonography to be an echogenic mass lying adjacent to the right kidney. Selective renal arteriography showed the lateral border of the right kidney to be compressed by a vascular tumor that was supplied by a leash of vessels radiating from the mid lateral border of the right kidney (fig. 1). At operation a well encapsulated tumor measuring approximately 12 cm. in diameter was found to be adherent to the right kidney. The kidney and tumor were removed. Gross examination of the specimen showed that the right kidney was separable easily from the capsule, which was split to enclose a tumor completely. The tumor had a homogeneous grayish-white cut surface (fig. 2). Microscopically, the tumor was composed of spindle cells arranged in interlacing and wavy bundles. The nuclei were ovoid to elongated. Moderate nuclear pleomorphism and hyperchromatism were present. Mitosis was infrequent. In focal areas the tumor cells exhibited fibrillary cytoplasm, and longitudinal myofibrils were demonstrated by phosphotungstic acidhematoxylin and trichrome stains. The outer third of the collagen bundles of the capsule continued on the surface of the tumor, while the rest of the capsule fibers remained between the tumor and kidney (fig. 3, A). Pathological diagnosis was leiomyosarcoma of the renal capsule.
FIG. 1. Selective renal arteriogram shows sun-ray appearance of neovasculature, arising from renal arterial branches.
COMMENT
The origin of leiomyosarcoma of the kidney remains speculative, including possibly 1) smooth muscle rests in the renal Accepted for publication January 17, 1985. 834
FIG. 2. Capsule ( C) could be stripped easily from kidney (K). Capsule split into 2 layers to invest whole tumor (T). Arrow indicates area shown microscopically in figure 3.
PRIIViAR'l LEIOMYOSARCOMA OF RENAL CAPSULE
B
835
parenchyma, 2) smooth muscle fiber in the renal pelvis, 3) renal capsule and 4) wall of the renal vessels. A detailed scrutiny of the literature revealed that in most cases the tumors arose from the renal pelvis, or were so big that they replaced part or all of the kidney, leaving no clue to the origin. In 1948 Cahill first speculated that leiomyosarcoma of the kidney might arise from the capsule. 1 Although often quoted, this hypothesis has never been proved. Of all 90 or so reported cases none presented convincing evidence to support the capsular origin of the tumor. Tetelman and Lisa described briefly a leiomyosarcoma in the form of a nodule attached to the cortical surface of the kidney. 2 No further information was available. Busuttil and More also reported what they believed to be a case of leiomyosarcoma of the renal capsule. 3 However, the same picture could well be given by any retroperitoneal tumor well circumscribed by a fibrous capsule, part of which happened to merge with the renal capsule. Recently, Bruneton and associates argued in favor of a renal capsule origin on the evidence that the tumor was supplied by what they called a renal capsular artery, which is, in fact, an early branch of the renal artery. 4 On the contrary, in our case the radiographic features, as well as the gross and microscopic appearances of complete enclosure of the tumor by split layers of the renal capsule left no doubt as to the capsular origin of the neoplasm. The renal capsule consists of whitish fibrous tissue with a few yellow elastic and smooth muscle fibers. 5 Smooth muscle cells also are present in the tunica media of small vessels, lying amid bundles of collagen fibers (fig. 3, B). It is reasonable to speculate that a leiomyosarcoma can develop from these 2 sources of smooth muscle elements. REFERENCES 1. Cahill, G. F., Jr.: Cancer of kidneys, adrenals and testes. J.A.M.A.,
FIG. 3. A, low power view of area indicated by arrow in figure 2. Note direction of splitting of fibrous capsule is towards tumor, quite unlike that of hypothetical case in which fibrous coat of retroperitoneal tumor merges secondarily with renal capsule. K, site previously occupied by kidney. van Gieson's stain, reduced from Xl6. B, arterioles inside renal capsule can be origin of tumor. H & E, reduced from X40.
138: 357, 1948. 2. Tetelman, M. M. and Lisa, J. R.: Leiomyosarcoma of the kidney: report of two cases. J. Urol., 54: 224, 1945. 3. Busuttil, A. and More, I. A. R.: Two malignant soft tissue tumors of the kidney: an ultrastructural appraisal. J. Urol., 112: 24, 1974. 4. Bruneton, J. N., Monticelli, J., Ettore, F. and Lesbats, G.: Leiomyosarcome de la capsule renale. Aspects echographique et angiographique. Apropos d'un cas. J. Rad., 61: 813, 1980.
Vol. 133, May
Copyright © 1985 by The Williams & Wilkins Co.
Printed in U.S.A.
Case Reports PRIMARY LEIOMYOSARCOMA OF RENAL CAPSULE W. D. NG, K. W. CHAN
AND
Y. T. CHAN
From the Surgical "B" Unit and Clinical Patlwlogy Institute, Princess Margaret Hospital, Kowloon, Hong Kong
ABSTRACT
The renal capsule long has been suggested to be the origin of leiomyosarcoma of the kidney but this speculation has never been proved. We describ~ a case of leiomyosarcoma lying within the renal capsule. The radiographic, as well as the macroscopic and microscopic appearances provide convincing evidence of capsular origin. Primary leiomyosarcoma of the kidney is a rare neoplasm. To date, approximately 90 cases have been described in the literature. Well documented cases of leiomyosarcoma of the renal capsule, if any, are much rarer. We report a case of leiomyosarcoma of the kidney capsule that presented distinctive morpholo°gical and radiographic features, making it the most well substantiated case. CASE REPORT
A 37-year-old man was hospitalized with a 1-month history of dull, aching right loin pain. He also became aware of an expanding lump in the right side of the abdomen. There was no history of hematuria or other urinary symptoms. Weight loss was 5 kg. during the same period. Physical examination was unremarkable except for a ballotable mass in the right flank, which was smooth and slightly tender. An abdominal x-ray revealed a soft tissue shadow in the right upper quadrant, which was confirmed later by ultrasonography to be an echogenic mass lying adjacent to the right kidney. Selective renal arteriography showed the lateral border of the right kidney to be compressed by a vascular tumor that was supplied by a leash of vessels radiating from the mid lateral border of the right kidney (fig. 1). At operation a well encapsulated tumor measuring approximately 12 cm. in diameter was found to be adherent to the right kidney. The kidney and tumor were removed. Gross examination of the specimen showed that the right kidney was separable easily from the capsule, which was split to enclose a tumor completely. The tumor had a homogeneous grayish-white cut surface (fig. 2). Microscopically, the tumor was composed of spindle cells arranged in interlacing and wavy bundles. The nuclei were ovoid to elongated. Moderate nuclear pleomorphism and hyperchromatism were present. Mitosis was infrequent. In focal areas the tumor cells exhibited fibrillary cytoplasm, and longitudinal myofibrils were demonstrated by phosphotungstic acidhematoxylin and trichrome stains. The outer third of the collagen bundles of the capsule continued on the surface of the tumor, while the rest of the capsule fibers remained between the tumor and kidney (fig. 3, A). Pathological diagnosis was leiomyosarcoma of the renal capsule.
FIG. 1. Selective renal arteriogram shows sun-ray appearance of neovasculature, arising from renal arterial branches.
COMMENT
The origin of leiomyosarcoma of the kidney remains speculative, including possibly 1) smooth muscle rests in the renal Accepted for publication January 17, 1985. 834
FIG. 2. Capsule ( C) could be stripped easily from kidney (K). Capsule split into 2 layers to invest whole tumor (T). Arrow indicates area shown microscopically in figure 3.
PRIIViAR'l LEIOMYOSARCOMA OF RENAL CAPSULE
B
835
parenchyma, 2) smooth muscle fiber in the renal pelvis, 3) renal capsule and 4) wall of the renal vessels. A detailed scrutiny of the literature revealed that in most cases the tumors arose from the renal pelvis, or were so big that they replaced part or all of the kidney, leaving no clue to the origin. In 1948 Cahill first speculated that leiomyosarcoma of the kidney might arise from the capsule. 1 Although often quoted, this hypothesis has never been proved. Of all 90 or so reported cases none presented convincing evidence to support the capsular origin of the tumor. Tetelman and Lisa described briefly a leiomyosarcoma in the form of a nodule attached to the cortical surface of the kidney. 2 No further information was available. Busuttil and More also reported what they believed to be a case of leiomyosarcoma of the renal capsule. 3 However, the same picture could well be given by any retroperitoneal tumor well circumscribed by a fibrous capsule, part of which happened to merge with the renal capsule. Recently, Bruneton and associates argued in favor of a renal capsule origin on the evidence that the tumor was supplied by what they called a renal capsular artery, which is, in fact, an early branch of the renal artery. 4 On the contrary, in our case the radiographic features, as well as the gross and microscopic appearances of complete enclosure of the tumor by split layers of the renal capsule left no doubt as to the capsular origin of the neoplasm. The renal capsule consists of whitish fibrous tissue with a few yellow elastic and smooth muscle fibers. 5 Smooth muscle cells also are present in the tunica media of small vessels, lying amid bundles of collagen fibers (fig. 3, B). It is reasonable to speculate that a leiomyosarcoma can develop from these 2 sources of smooth muscle elements. REFERENCES 1. Cahill, G. F., Jr.: Cancer of kidneys, adrenals and testes. J.A.M.A.,
FIG. 3. A, low power view of area indicated by arrow in figure 2. Note direction of splitting of fibrous capsule is towards tumor, quite unlike that of hypothetical case in which fibrous coat of retroperitoneal tumor merges secondarily with renal capsule. K, site previously occupied by kidney. van Gieson's stain, reduced from Xl6. B, arterioles inside renal capsule can be origin of tumor. H & E, reduced from X40.
138: 357, 1948. 2. Tetelman, M. M. and Lisa, J. R.: Leiomyosarcoma of the kidney: report of two cases. J. Urol., 54: 224, 1945. 3. Busuttil, A. and More, I. A. R.: Two malignant soft tissue tumors of the kidney: an ultrastructural appraisal. J. Urol., 112: 24, 1974. 4. Bruneton, J. N., Monticelli, J., Ettore, F. and Lesbats, G.: Leiomyosarcome de la capsule renale. Aspects echographique et angiographique. Apropos d'un cas. J. Rad., 61: 813, 1980.