Rectal Obstruction Secondary to Carcinoma of the Prostate DONALD E. FRY, M.D., MOHAMMAD AMIN, M.D., PHIL J. HARBRECHT, M.D.
The records of 13 patients with symptomatic rectal obstruction secondary to prostatic carcinoma have been critically reviewed to provide criteria for identifying this atypical presentation. The site of obstruction varied from the anal verge to 17 cm by sigmoidoscopy. Significant clinical findings were ureteral obstruction on excretory urography in 12 of the patients, elevated acid phosphatase in eight, intact mucosa over the obstructing mass in seven and osteoblastic bone metastasis in six. Primary diagnosis was generally established by comparing histopathologically the prostate and the obstructing lesion. Colostomy was necessary in nine cases. In three patients colostomy was obviated in partially obstructing lesions by intravenous diethylstilbestrol diphosphate therapy. One patient had an inappropriate low anterior resection. Rectal obstruction is most commonly due to primary adenocarcinoma. Occasionally the obstruction is secondary to prostatic carcinoma masquerading as an intrinsic rectal cancer. Identification of the true nature of the illness is essential for proper treatment.
V MARY ADENOCARCINOMA of both the rectosigmoid colon and prostate, ordinarily present in a characteristic fashion. Diagnostic measures are standardized and a histopathological diagnosis is easily achieved. On occasion, however, prostatic adenocarcinoma may invade or may actually metastasize to the rectosigmoid colon and result in partial or complete luminal obstruction. An evaluation encompassing histopathological examination ofthe lesion without consideration of clinical details may result in an incorrect diagnosis of primary rectal carcinoma. Anatomic topography is not a useful discriminate in recognizing the source of obstruction because the primary lesion of rectosigmoid colon carcinoma is frequently close to the prostate. Identification of the true primary carcinoma is obviously essential to proper therapy. Patients and Methods In an effort to define criteria to establish the true primary nature of obstructing rectal lesions, the clinical records of 13 patients with rectal obstruction secondary Reprint requests: Donald E. Fry, M.D., Department of Surgery, University of Louisville School of Medicine, Health Sciences Center, P.O. Box 35260, Louisville, Kentucky 40232. Submitted for publication: May 28, 1978.
From the Department of Surgery, University of Louisville School of Medicine, Health Sciences Center, and the Surgical Service, Veterans Administration Hospital, Louisville, Kentucky
to histologically proven prostatic carcinoma were reviewed. All were patients at either Louisville General Hospital or Louisville Veterans Administration Hospital from 1966 to 1976. Signs and symptoms of each clinical presentation were examined. Results of all diagnostic tests, including serum chemistries, proctosigmoidoscopy, radiologic studies, and histopathological interpretations of the obstructing lesions were tabulated. The working diagnosis and initial interpretations of each case were noted and clinical evidence which subsequently directed the evaluation to the correct diagnosis was assessed. The various therapeutic measures employed in the treatment of rectal obstruction and of the primary prostatic carcinoma were examined to determine the most appropriate action in the management of this unusual problem.
Results
The age distribution of the 13 patients was 55-87 years with a mean age of 71. Eight of the patients were white, five were black. Symptomatology at initial presentation was quite similar to that of primary rectosigmoid carcinoma (Table 1). All patients gave a history of constipation and abdominal pain. Four patients had intermittent diarrhea and constipation prior to admission. Six patients had bright red rectal bleeding. Rectal tenesmus was present in three cases. Onset of symptoms of obstruction was one week to six months prior to
admission. Of particular interest were symptoms of urinary tract obstruction. Six patients had no history of hesitancy or dysuria. Two patients had undergone previous operative procedures for prostatic carcinoma but were asymptomatic in this respect at the time of presentation with rectal obstruction. The remaining five patients had concurrent urinary hesitancy or dysuria or both. Only
0003-4932/79/0400/0488 $00.75 © J. B. Lippincott Company
488
Vol. 189 a No. 4
RECTAL OBSTRUCTION IN PROSTATIC CARCINOMA
five of the 13 patients had a diagnosis of prostatic carcinoma prior to onset of rectal obstruction. The site of obstruction varied from the anal verge to 17 cm by proctosigmoidoscopy. In five cases the obstructing lesion was not palpable via digital examination of the rectum because of the proximal location of the lesion. In ten cases the lesion was annular. Gross ulceration of the mucosa was identified at proctosigmoidoscopy in six patients, while the remainder had completely intact rectal mucosa overlying the obstruction. When present, the intact mucosa is a significant indicator of the extrinsic nature of rectal obstruction secondary to primary prostatic carcinoma. In four patients, combined rectal and proctosigmoidoscopic examinations failed to identify the obstructing mass as contiguous with the prostate gland. Digital examination of the prostate gland itself was of marginal value in ascertaining the true primary carcinoma. In four cases the gland could not be palpated because of the obstructing lesion and in two cases the gland was deemed to be normal in size and texture by
_
s
'rE
_
489
TABLE 1. Symptoms Noted at Initial Presentation
Symptoms
No. of Patients
Abdominal pain Constipation Rectal bleeding Dysuria Intermittent diarrhea Rectal tenesmus
13 13 6 5 4 3
experienced examiners. In three cases, the prostate gland was massive and was clinically the obvious source of obstruction. In the remaining cases, the prostate was slightly enlarged but not particularly unusual for this age group of patients. Conventional enzyme determinations were of limited value in identifying the prostatic primary tumor. Eight patients had elevated acid phosphatase at the time of obstruction; five of these patients had antecedent diagnoses of prostatic carcinoma. Only two patients had elevations of alkaline phosphatase despite the presence of bony metastasis in six patients. Excretory urography was the most consistently positive study, disclosing various degrees of ureteral
ie~~~4
X 9hI
.
FIG. Ia. Excretory urogram demonstrating severe bilateral hydronephrosis in a patient with partial rectal obstruction secondary to prostatic carcinoma.
FIG. lb. Follow-up excretory urogram performed one year after initiation of estrogen therapy and course of pelvic radiation. The bilateral hydronephrosis has resolved.
FRY, AMIN AND HARBRECHT
490
Ann. Surg. * April 1979
In one patient a low anterior resection was performed because the surgeon was committed to resection (the sigmoid colon had been divided proximally) before recognizing the extrinsic nature of the disease process. Despite estrogen therapy, this patient developed severe metastatic disease and died nine months following operation. In three cases with partially obstructing lesions, proximal diversion was avoided by prompt recognition of the true primary pathologic status and initiation of intravenous diethylstilbestrol diphosphate therapy (Stilphostrolg, Dome Laboratories, West Haven, Connecticut). This resulted in a dramatic regression of the obstructing mass (Figs. lb and 3). All three patients are alive at 20, 22, and 49 months on continued estrogen therapy. One of these patients has undergone pelvic irradiation, one has undergone orchiectomy, while the third patient has been maintained on oral estrogens alone. No obstructive symptoms have recurred. A-.-
FIG. 2. Lateral view of barium enema contrast study in the same patient. Note the degree of rectal obstruction (arrows).
obstruction in 12 cases (Fig. la). In nine cases the ureteral obstruction was bilateral. The only case without urographic evidence of ureteral obstruction had a low lying obstructing lesion at the anal verge of the rectum. On the other hand, the barium enema contrast study was not useful other than for defining the level of obstruction and in demonstrating the characteristic long segment involvement (Fig. 2).1 In the eight cases where barium enemas were performed, radiological interpretation was consistently primary colorectal cancer. The histopathological diagnosis of primary adenocarcinoma of the prostate was established by transrectal or transperineal biopsy in ten cases. Retropubic biopsy of the prostate was employed in one patient. In two other cases, the diagnosis was established at autopsy. The histopathology was typically poorly differentiated. In each case, the histopathology of the prostatic biopsy was compared to the biopsy of the obstructing lesion. This allowed confirmation of the common histological origin of the tissue and eliminated the possibility of synchronous primary lesions. In nine cases, colostomy was necessary to effect colonic decompression and avoid proximal perforation. Estrogens were the primary treatment of the prostatic carcinoma following colostomy. Of these nine patients, six are dead following a mean survival of 15 months. Three patients are alive nine, 18, and 26 months following colostomy.
Discussion Reports have described primary adenocarcinoma of the prostate causing rectal obstruction that clinically resembles intrinsic colorectal carcinoma.",5'6 However, most studies dealt with only one case or a very small number of cases and failed to define criteria that would assist the surgeon in rapidly establishing the true nature of a suspicious rectal mass. Signs and symptoms are not useful in determining diagnosis. Symptoms ofobstruction which may include rectal bleeding are as those of primary colorectal neoplasm. In many cases, antecedent history of prostatic
FIG. 3. Illustrates resolution of the obstruction after two weeks of administration of intravenous diethylstilbestrol diphosphate.
Vol. 189 * No. 4
carcinoma and urinary tract symptoms are absent. Rectal examination frequently discloses the obstructing lesion to be annular (as in colon carcinoma) and the digital palpatory examination of the prostate may be minimally abnormal or even completely unremarkable. Continuity between the obstruction and the prostate gland may not be evidenced. The obstructing lesion has been described as actually representing a metastatic lesion.7 Obstruction may occur by direct local extension of the massively enlarged prostate into the rectal lumen. Finally, obstruction may be secondary to invasion about the rectum resulting in an annular lesion such as was most commonly seen in this series (Figs. 4a and b). Whether obstruction results from an annular lesion, direct protrusion, or a metastatic focus, mucosal ulceration may be present thereby further confusing the issue. Mucosal integrity overlying the lesion is suggestive of an extrinsic primary process such as carcinoma of the prostate. Histopathological diagnosis of the obstructing mass will be adenocarcinoma in either situation. The observations in this series of patients indicate that histopathology tends to be poorly differentiated when obstruction is secondary to a prostatic primary process. The pathologist is frequently unable to identify histological features that determine the cellular origin. Accordingly, special staining techniques to identify mucin have been utilized since mucin is normally produced by colonic mucosa. Unfortunately, false-positive mucin stains of prostatic tissue preclude the value of this method.3 Additionally, acid phosphatase stains have been used to define histologically tissue of prostatic origin but this method has not been uniformly satisfactory because of false-positive stains in large bowel carcinomas.2 Because of the pathologic similarity of these lesions and the absence of detectable acid phosphate in the serum, the concentration of cellular acid phosphatase may be quite low. The value of such a stain in this specific group of prostatic carcinomas must be more carefully assessed before it can be recommended as a useful diagnostic discriminant. Elevation of serum acid phosphatase was useful when present. Determinations of the prostatic fractions of acid phosphatase are more diagnostically useful than total serum values. Recognition of characteristic osteoTABLE 2. Clinical Indicators of Rectal Obstruction Secondary to Prostatic Carcinoma 1. 2. 3. 4.
491
RECTAL OBSTRUCTION IN PROSTATIC CARCINOMA
Unilateral or bilateral ureteral obstruction Mucosal integrity over the obstructing lesion Characteristic osteoblastic bony metastasis Elevated acid phosphatase (prostatic fraction)
/ a
h
..
)
/,.:;:
.......
C
FIG. 4. Illustrates the low (a) and high (b) annular obstruction of the rectum secondary to locally invasive adenocarcinoma of the prostate and carcinoma of the prostate and the rectum occurring as synchronous lesions (c).
492
Ann. Surg. * April 1979
FRY, AMIN AND HARBRECHT
blastic metastases are likewise important aids in differentiating the two entities. Perhaps the most consistent finding in this unusual presentation is the almost uniform presence of ureteral dilatation. While primary adenocarcinoma of the rectosigmoid colon may cause ureteral occlusion by invading the urinary bladder trigone, such occlusion is not commonly associated with rectosigmoid carcinoma. Cystoscopy may be useful in the assessment of ureteral obstruction. Biopsy of a prostatic specimen which is as far from the obstructing lesion as possible is important for establishing the diagnosis. Such biopsy is best performed by the transrectal or transperineal approach. Transurethral biopsy may be most appropriate to obstructions about the anal verge. In one patient, retropubic biopsy was employed at exploration for colostomy decompression to achieve the tissue diagnosis. If the prostatic biopsy is positive for carcinoma, histological comparison with the obstructing lesion should then be employed to prove or disprove synchronous primary processes (Fig. 4c). The significance of proper diagnosis resides in the dramatically different therapeutic measures. One patient in this series underwent resectional therapy for the wrong primary disease. Another report describes similar cases.4 A fixed pelvic mass of colonic origin carries a grave prognosis in terms of both survival and quality of life. On the other hand, nearly 80% of pros-
tatic carcinomas are hormonally sensitive, thus significant, quality palliation can be achieved.7 In the patient with acute obstruction of the colon and threatened proximal perforation, decompressive colostomy is always essential; determinations of primary pathology can be pursued electively. However, in the patient with a partially obstructing lesion, expeditious determination of primary prostatic carcinoma as the cause allows institution of intravenous diethylstilbestrol diphosphate therapy and possible avoidance of colostomy. References 1. Gengler, L., Baer, J. and Finby, N.: Rectal and Sigmoid Involvement Secondary to Carcinoma of the Prostate. Am. J. Roentgenol. Radium Ther. Nucl. Med., 125:910, 1975. 2. Gomori, G.: Distribution of Acid Phosphatase in Tissues Under Normal and Under Pathologic Conditions. Arch. Pathol., 32: 189, 1941. 3. Levine, A. J. and Foster, E. A.: The Relation of Mucicarminestaining Properties of Carcinomas of the Prostate to Differentiation, Metastasis, and Prognosis. Cancer, 17:21, 1964. 4. Mir, M., Dikranian, H. and Cogbill, C. L.: Carcinoma of the Prostate Presenting as Obstructive Carcinoma of the Rectum. Am. Surg., 39:582, 1973. 5. Olsen, B. S. and Carlisle, R. W.: Adenocarcinoma of the Prostate Simulating Primary Rectal Malignancy. Cancer, 25:219, 1970. 6. Sweitzer, S., Hagihara, P. and McRoberts, J. W.: Carcinoma of the Prostate Presenting Initially as Carcinoma of the Rectum. Am. Surg., 43:751, 1977. 7. Winter, C. C.: The Problem of Rectal Involvement by Prostatic Cancer. Surg. Gynecol. Obstet., 105:136, 1957.
Announcement The appearance of the code at the bottom of the first page of an article in this journal indicates the copyright owner's consent that copies of the article may be made for personal or internal use, or for personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay the stated per-copy fee through the Copyright Clearance Center Inc., P.O. Box 765, Schenectady, N.Y. 12301, for copying beyond that permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying, such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale.
The records of 13 patients with symptomatic rectal obstruction secondary to prostatic carcinoma have been critically reviewed to provide criteria for identifying this atypical presentation. The site of obstruction varied from the anal verge to 17 cm by sigmoidoscopy. Significant clinical findings were ureteral obstruction on excretory urography in 12 of the patients, elevated acid phosphatase in eight, intact mucosa over the obstructing mass in seven and osteoblastic bone metastasis in six. Primary diagnosis was generally established by comparing histopathologically the prostate and the obstructing lesion. Colostomy was necessary in nine cases. In three patients colostomy was obviated in partially obstructing lesions by intravenous diethylstilbestrol diphosphate therapy. One patient had an inappropriate low anterior resection. Rectal obstruction is most commonly due to primary adenocarcinoma. Occasionally the obstruction is secondary to prostatic carcinoma masquerading as an intrinsic rectal cancer. Identification of the true nature of the illness is essential for proper treatment.
V MARY ADENOCARCINOMA of both the rectosigmoid colon and prostate, ordinarily present in a characteristic fashion. Diagnostic measures are standardized and a histopathological diagnosis is easily achieved. On occasion, however, prostatic adenocarcinoma may invade or may actually metastasize to the rectosigmoid colon and result in partial or complete luminal obstruction. An evaluation encompassing histopathological examination ofthe lesion without consideration of clinical details may result in an incorrect diagnosis of primary rectal carcinoma. Anatomic topography is not a useful discriminate in recognizing the source of obstruction because the primary lesion of rectosigmoid colon carcinoma is frequently close to the prostate. Identification of the true primary carcinoma is obviously essential to proper therapy. Patients and Methods In an effort to define criteria to establish the true primary nature of obstructing rectal lesions, the clinical records of 13 patients with rectal obstruction secondary Reprint requests: Donald E. Fry, M.D., Department of Surgery, University of Louisville School of Medicine, Health Sciences Center, P.O. Box 35260, Louisville, Kentucky 40232. Submitted for publication: May 28, 1978.
From the Department of Surgery, University of Louisville School of Medicine, Health Sciences Center, and the Surgical Service, Veterans Administration Hospital, Louisville, Kentucky
to histologically proven prostatic carcinoma were reviewed. All were patients at either Louisville General Hospital or Louisville Veterans Administration Hospital from 1966 to 1976. Signs and symptoms of each clinical presentation were examined. Results of all diagnostic tests, including serum chemistries, proctosigmoidoscopy, radiologic studies, and histopathological interpretations of the obstructing lesions were tabulated. The working diagnosis and initial interpretations of each case were noted and clinical evidence which subsequently directed the evaluation to the correct diagnosis was assessed. The various therapeutic measures employed in the treatment of rectal obstruction and of the primary prostatic carcinoma were examined to determine the most appropriate action in the management of this unusual problem.
Results
The age distribution of the 13 patients was 55-87 years with a mean age of 71. Eight of the patients were white, five were black. Symptomatology at initial presentation was quite similar to that of primary rectosigmoid carcinoma (Table 1). All patients gave a history of constipation and abdominal pain. Four patients had intermittent diarrhea and constipation prior to admission. Six patients had bright red rectal bleeding. Rectal tenesmus was present in three cases. Onset of symptoms of obstruction was one week to six months prior to
admission. Of particular interest were symptoms of urinary tract obstruction. Six patients had no history of hesitancy or dysuria. Two patients had undergone previous operative procedures for prostatic carcinoma but were asymptomatic in this respect at the time of presentation with rectal obstruction. The remaining five patients had concurrent urinary hesitancy or dysuria or both. Only
0003-4932/79/0400/0488 $00.75 © J. B. Lippincott Company
488
Vol. 189 a No. 4
RECTAL OBSTRUCTION IN PROSTATIC CARCINOMA
five of the 13 patients had a diagnosis of prostatic carcinoma prior to onset of rectal obstruction. The site of obstruction varied from the anal verge to 17 cm by proctosigmoidoscopy. In five cases the obstructing lesion was not palpable via digital examination of the rectum because of the proximal location of the lesion. In ten cases the lesion was annular. Gross ulceration of the mucosa was identified at proctosigmoidoscopy in six patients, while the remainder had completely intact rectal mucosa overlying the obstruction. When present, the intact mucosa is a significant indicator of the extrinsic nature of rectal obstruction secondary to primary prostatic carcinoma. In four patients, combined rectal and proctosigmoidoscopic examinations failed to identify the obstructing mass as contiguous with the prostate gland. Digital examination of the prostate gland itself was of marginal value in ascertaining the true primary carcinoma. In four cases the gland could not be palpated because of the obstructing lesion and in two cases the gland was deemed to be normal in size and texture by
_
s
'rE
_
489
TABLE 1. Symptoms Noted at Initial Presentation
Symptoms
No. of Patients
Abdominal pain Constipation Rectal bleeding Dysuria Intermittent diarrhea Rectal tenesmus
13 13 6 5 4 3
experienced examiners. In three cases, the prostate gland was massive and was clinically the obvious source of obstruction. In the remaining cases, the prostate was slightly enlarged but not particularly unusual for this age group of patients. Conventional enzyme determinations were of limited value in identifying the prostatic primary tumor. Eight patients had elevated acid phosphatase at the time of obstruction; five of these patients had antecedent diagnoses of prostatic carcinoma. Only two patients had elevations of alkaline phosphatase despite the presence of bony metastasis in six patients. Excretory urography was the most consistently positive study, disclosing various degrees of ureteral
ie~~~4
X 9hI
.
FIG. Ia. Excretory urogram demonstrating severe bilateral hydronephrosis in a patient with partial rectal obstruction secondary to prostatic carcinoma.
FIG. lb. Follow-up excretory urogram performed one year after initiation of estrogen therapy and course of pelvic radiation. The bilateral hydronephrosis has resolved.
FRY, AMIN AND HARBRECHT
490
Ann. Surg. * April 1979
In one patient a low anterior resection was performed because the surgeon was committed to resection (the sigmoid colon had been divided proximally) before recognizing the extrinsic nature of the disease process. Despite estrogen therapy, this patient developed severe metastatic disease and died nine months following operation. In three cases with partially obstructing lesions, proximal diversion was avoided by prompt recognition of the true primary pathologic status and initiation of intravenous diethylstilbestrol diphosphate therapy (Stilphostrolg, Dome Laboratories, West Haven, Connecticut). This resulted in a dramatic regression of the obstructing mass (Figs. lb and 3). All three patients are alive at 20, 22, and 49 months on continued estrogen therapy. One of these patients has undergone pelvic irradiation, one has undergone orchiectomy, while the third patient has been maintained on oral estrogens alone. No obstructive symptoms have recurred. A-.-
FIG. 2. Lateral view of barium enema contrast study in the same patient. Note the degree of rectal obstruction (arrows).
obstruction in 12 cases (Fig. la). In nine cases the ureteral obstruction was bilateral. The only case without urographic evidence of ureteral obstruction had a low lying obstructing lesion at the anal verge of the rectum. On the other hand, the barium enema contrast study was not useful other than for defining the level of obstruction and in demonstrating the characteristic long segment involvement (Fig. 2).1 In the eight cases where barium enemas were performed, radiological interpretation was consistently primary colorectal cancer. The histopathological diagnosis of primary adenocarcinoma of the prostate was established by transrectal or transperineal biopsy in ten cases. Retropubic biopsy of the prostate was employed in one patient. In two other cases, the diagnosis was established at autopsy. The histopathology was typically poorly differentiated. In each case, the histopathology of the prostatic biopsy was compared to the biopsy of the obstructing lesion. This allowed confirmation of the common histological origin of the tissue and eliminated the possibility of synchronous primary lesions. In nine cases, colostomy was necessary to effect colonic decompression and avoid proximal perforation. Estrogens were the primary treatment of the prostatic carcinoma following colostomy. Of these nine patients, six are dead following a mean survival of 15 months. Three patients are alive nine, 18, and 26 months following colostomy.
Discussion Reports have described primary adenocarcinoma of the prostate causing rectal obstruction that clinically resembles intrinsic colorectal carcinoma.",5'6 However, most studies dealt with only one case or a very small number of cases and failed to define criteria that would assist the surgeon in rapidly establishing the true nature of a suspicious rectal mass. Signs and symptoms are not useful in determining diagnosis. Symptoms ofobstruction which may include rectal bleeding are as those of primary colorectal neoplasm. In many cases, antecedent history of prostatic
FIG. 3. Illustrates resolution of the obstruction after two weeks of administration of intravenous diethylstilbestrol diphosphate.
Vol. 189 * No. 4
carcinoma and urinary tract symptoms are absent. Rectal examination frequently discloses the obstructing lesion to be annular (as in colon carcinoma) and the digital palpatory examination of the prostate may be minimally abnormal or even completely unremarkable. Continuity between the obstruction and the prostate gland may not be evidenced. The obstructing lesion has been described as actually representing a metastatic lesion.7 Obstruction may occur by direct local extension of the massively enlarged prostate into the rectal lumen. Finally, obstruction may be secondary to invasion about the rectum resulting in an annular lesion such as was most commonly seen in this series (Figs. 4a and b). Whether obstruction results from an annular lesion, direct protrusion, or a metastatic focus, mucosal ulceration may be present thereby further confusing the issue. Mucosal integrity overlying the lesion is suggestive of an extrinsic primary process such as carcinoma of the prostate. Histopathological diagnosis of the obstructing mass will be adenocarcinoma in either situation. The observations in this series of patients indicate that histopathology tends to be poorly differentiated when obstruction is secondary to a prostatic primary process. The pathologist is frequently unable to identify histological features that determine the cellular origin. Accordingly, special staining techniques to identify mucin have been utilized since mucin is normally produced by colonic mucosa. Unfortunately, false-positive mucin stains of prostatic tissue preclude the value of this method.3 Additionally, acid phosphatase stains have been used to define histologically tissue of prostatic origin but this method has not been uniformly satisfactory because of false-positive stains in large bowel carcinomas.2 Because of the pathologic similarity of these lesions and the absence of detectable acid phosphate in the serum, the concentration of cellular acid phosphatase may be quite low. The value of such a stain in this specific group of prostatic carcinomas must be more carefully assessed before it can be recommended as a useful diagnostic discriminant. Elevation of serum acid phosphatase was useful when present. Determinations of the prostatic fractions of acid phosphatase are more diagnostically useful than total serum values. Recognition of characteristic osteoTABLE 2. Clinical Indicators of Rectal Obstruction Secondary to Prostatic Carcinoma 1. 2. 3. 4.
491
RECTAL OBSTRUCTION IN PROSTATIC CARCINOMA
Unilateral or bilateral ureteral obstruction Mucosal integrity over the obstructing lesion Characteristic osteoblastic bony metastasis Elevated acid phosphatase (prostatic fraction)
/ a
h
..
)
/,.:;:
.......
C
FIG. 4. Illustrates the low (a) and high (b) annular obstruction of the rectum secondary to locally invasive adenocarcinoma of the prostate and carcinoma of the prostate and the rectum occurring as synchronous lesions (c).
492
Ann. Surg. * April 1979
FRY, AMIN AND HARBRECHT
blastic metastases are likewise important aids in differentiating the two entities. Perhaps the most consistent finding in this unusual presentation is the almost uniform presence of ureteral dilatation. While primary adenocarcinoma of the rectosigmoid colon may cause ureteral occlusion by invading the urinary bladder trigone, such occlusion is not commonly associated with rectosigmoid carcinoma. Cystoscopy may be useful in the assessment of ureteral obstruction. Biopsy of a prostatic specimen which is as far from the obstructing lesion as possible is important for establishing the diagnosis. Such biopsy is best performed by the transrectal or transperineal approach. Transurethral biopsy may be most appropriate to obstructions about the anal verge. In one patient, retropubic biopsy was employed at exploration for colostomy decompression to achieve the tissue diagnosis. If the prostatic biopsy is positive for carcinoma, histological comparison with the obstructing lesion should then be employed to prove or disprove synchronous primary processes (Fig. 4c). The significance of proper diagnosis resides in the dramatically different therapeutic measures. One patient in this series underwent resectional therapy for the wrong primary disease. Another report describes similar cases.4 A fixed pelvic mass of colonic origin carries a grave prognosis in terms of both survival and quality of life. On the other hand, nearly 80% of pros-
tatic carcinomas are hormonally sensitive, thus significant, quality palliation can be achieved.7 In the patient with acute obstruction of the colon and threatened proximal perforation, decompressive colostomy is always essential; determinations of primary pathology can be pursued electively. However, in the patient with a partially obstructing lesion, expeditious determination of primary prostatic carcinoma as the cause allows institution of intravenous diethylstilbestrol diphosphate therapy and possible avoidance of colostomy. References 1. Gengler, L., Baer, J. and Finby, N.: Rectal and Sigmoid Involvement Secondary to Carcinoma of the Prostate. Am. J. Roentgenol. Radium Ther. Nucl. Med., 125:910, 1975. 2. Gomori, G.: Distribution of Acid Phosphatase in Tissues Under Normal and Under Pathologic Conditions. Arch. Pathol., 32: 189, 1941. 3. Levine, A. J. and Foster, E. A.: The Relation of Mucicarminestaining Properties of Carcinomas of the Prostate to Differentiation, Metastasis, and Prognosis. Cancer, 17:21, 1964. 4. Mir, M., Dikranian, H. and Cogbill, C. L.: Carcinoma of the Prostate Presenting as Obstructive Carcinoma of the Rectum. Am. Surg., 39:582, 1973. 5. Olsen, B. S. and Carlisle, R. W.: Adenocarcinoma of the Prostate Simulating Primary Rectal Malignancy. Cancer, 25:219, 1970. 6. Sweitzer, S., Hagihara, P. and McRoberts, J. W.: Carcinoma of the Prostate Presenting Initially as Carcinoma of the Rectum. Am. Surg., 43:751, 1977. 7. Winter, C. C.: The Problem of Rectal Involvement by Prostatic Cancer. Surg. Gynecol. Obstet., 105:136, 1957.
Announcement The appearance of the code at the bottom of the first page of an article in this journal indicates the copyright owner's consent that copies of the article may be made for personal or internal use, or for personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay the stated per-copy fee through the Copyright Clearance Center Inc., P.O. Box 765, Schenectady, N.Y. 12301, for copying beyond that permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend to other kinds of copying, such as copying for general distribution, for advertising or promotional purposes, for creating new collective works, or for resale.
