326
BRITISH JOURNAL OF UROLOGY
Thon, W., Mohr, W. and Altwein, J. E. (1985). Hoden-und Nedenhodenmetastase eines Prostatakarzinorna. Urologe [ A ] , 24,287-290. Requests for reprints to: J . E. Heller, Department of Urology, St Paul-Ramsey Medical Center, 640 Jackson Street, St Paul, Minnesota 55101-2595, USA.
Recent Change in a Tailgut Cyst Presenting as Urinary Retention B. M. STEPHENSON, M. BARTLET, R. N1RULA.A. G. EVANS and A. M. REES, Departments of Surgery and Pathology, Princess of Wales Hospital, Bridgend
Tailgut cysts are uncommon developmental abnormalities and rarely undergo malignant change. We report the oldest and what we believe to be the first case presenting as urinary retention. Case Report An obese 81-year-old man presented in acute urinary retention. He gave a 6-week history of outflow obstruction. Four months previously he had been started on diuretics for lower limb oedema, presumed to be secondary to heart failure, but this had not cleared. Urethral catheterisation drained 800 ml of clear urine. Rectal examination revealed a 40 g benign prostate. His blood urea was 16 mmol/l and creatinine 230 pmol/l. An attempt at transurethral resection was unsuccessful because of angulation and anterior displacement of the prostatic urethra. The procedure was abandoned and a suprapubic cystostomy performed. Subsequent investigations, including a CT scan (Fig.), confirmed a well defined, partly calcified cystic mass, 13 cm in diameter, arising from the pelvis and extending up to the origin of the inferior vena cava. Both ureters were dilated. At laparotomy the mass originating from the pre-sacral space was separate from, but displacing the rectum, bladder and prostate. By a combination of sharp and blunt dissection it was removed from its attachment to the lower part of the sacrum. On the third post-operative day the patient suffered a fatal cerebrovascular accident. Histology showed a thin-walled cyst filled with mucus, with scanty velvety areas on its inner surface. Only these areas showed any epithelium, which was severely dysplastic. The wall consisted of bland fibrous tissue only, with focal calcification but no muscle component.
Comment
The origin of this mucin-producing cystadenoma is debatable. The possibility that it was a pre-sacral teratoma was discounted by virtue of the patient’s age and the lack of a second epithelial type or stromal component. The lack of a primary tumour
Fig. CT scan of pelvis showing a large, partly calcified cyst lying behind the bladder.
at post mortem or relevant previous surgery makes a metastatic deposit unlikely. Cystadenomas, at this site, and of Mullerian origin, have been described, but only in females. Tailgut cysts are uncommon but recognised entities in this location. The classification of these cysts appears to overlap with that of rectal duplication cysts. Tailgut cysts are believed to be remnants of the embryological tail duct which disappears at the 8 mm stage (Caropreso et al., 1975) and rectal duplication cysts to be “pinched off’ remnants (Weitzel and Breed, 1963). Rectal duplication cysts, and not tailgut cysts, are said to possess well defined muscle layers (Weitzel and Breed, 1963; Hjermstad and Helwig, 1988). We consider a tailgut cyst to be the most likely origin of this tumour, but the lack of residual bowel mucosa precludes a definitive diagnosis. The cyst had probably been in place for many years and it was only the relatively recent neoplastic transformation that caused marked enlargement and clinical symptoms. References Caropreso, P. R., Wengart, P. A. and Milford, H. E. (1975). Tailgut cyst-a rare retrorectal tumour. Dis. Colon Rectum, 18, 597-600. Hjermstad, B. M. and Helwig, E. B. (1988). Tailgut cysts. Am. J . Clin. Pathol., 89, 139-147. Weitzel, R. A. and Breed, J. R. (1963). Carcinoma arising in a rectal duplication. Ann. Surg., 157,476-480. Requests for reprints to: B. M. Stephenson, Coloproctology Research Fellow, Imperial Cancer Research Fund, Genetic Epidemiology Laboratory, 3K Springfield House, Hyde Terrace, Leeds LS2 9LU.
BRITISH JOURNAL OF UROLOGY
Thon, W., Mohr, W. and Altwein, J. E. (1985). Hoden-und Nedenhodenmetastase eines Prostatakarzinorna. Urologe [ A ] , 24,287-290. Requests for reprints to: J . E. Heller, Department of Urology, St Paul-Ramsey Medical Center, 640 Jackson Street, St Paul, Minnesota 55101-2595, USA.
Recent Change in a Tailgut Cyst Presenting as Urinary Retention B. M. STEPHENSON, M. BARTLET, R. N1RULA.A. G. EVANS and A. M. REES, Departments of Surgery and Pathology, Princess of Wales Hospital, Bridgend
Tailgut cysts are uncommon developmental abnormalities and rarely undergo malignant change. We report the oldest and what we believe to be the first case presenting as urinary retention. Case Report An obese 81-year-old man presented in acute urinary retention. He gave a 6-week history of outflow obstruction. Four months previously he had been started on diuretics for lower limb oedema, presumed to be secondary to heart failure, but this had not cleared. Urethral catheterisation drained 800 ml of clear urine. Rectal examination revealed a 40 g benign prostate. His blood urea was 16 mmol/l and creatinine 230 pmol/l. An attempt at transurethral resection was unsuccessful because of angulation and anterior displacement of the prostatic urethra. The procedure was abandoned and a suprapubic cystostomy performed. Subsequent investigations, including a CT scan (Fig.), confirmed a well defined, partly calcified cystic mass, 13 cm in diameter, arising from the pelvis and extending up to the origin of the inferior vena cava. Both ureters were dilated. At laparotomy the mass originating from the pre-sacral space was separate from, but displacing the rectum, bladder and prostate. By a combination of sharp and blunt dissection it was removed from its attachment to the lower part of the sacrum. On the third post-operative day the patient suffered a fatal cerebrovascular accident. Histology showed a thin-walled cyst filled with mucus, with scanty velvety areas on its inner surface. Only these areas showed any epithelium, which was severely dysplastic. The wall consisted of bland fibrous tissue only, with focal calcification but no muscle component.
Comment
The origin of this mucin-producing cystadenoma is debatable. The possibility that it was a pre-sacral teratoma was discounted by virtue of the patient’s age and the lack of a second epithelial type or stromal component. The lack of a primary tumour
Fig. CT scan of pelvis showing a large, partly calcified cyst lying behind the bladder.
at post mortem or relevant previous surgery makes a metastatic deposit unlikely. Cystadenomas, at this site, and of Mullerian origin, have been described, but only in females. Tailgut cysts are uncommon but recognised entities in this location. The classification of these cysts appears to overlap with that of rectal duplication cysts. Tailgut cysts are believed to be remnants of the embryological tail duct which disappears at the 8 mm stage (Caropreso et al., 1975) and rectal duplication cysts to be “pinched off’ remnants (Weitzel and Breed, 1963). Rectal duplication cysts, and not tailgut cysts, are said to possess well defined muscle layers (Weitzel and Breed, 1963; Hjermstad and Helwig, 1988). We consider a tailgut cyst to be the most likely origin of this tumour, but the lack of residual bowel mucosa precludes a definitive diagnosis. The cyst had probably been in place for many years and it was only the relatively recent neoplastic transformation that caused marked enlargement and clinical symptoms. References Caropreso, P. R., Wengart, P. A. and Milford, H. E. (1975). Tailgut cyst-a rare retrorectal tumour. Dis. Colon Rectum, 18, 597-600. Hjermstad, B. M. and Helwig, E. B. (1988). Tailgut cysts. Am. J . Clin. Pathol., 89, 139-147. Weitzel, R. A. and Breed, J. R. (1963). Carcinoma arising in a rectal duplication. Ann. Surg., 157,476-480. Requests for reprints to: B. M. Stephenson, Coloproctology Research Fellow, Imperial Cancer Research Fund, Genetic Epidemiology Laboratory, 3K Springfield House, Hyde Terrace, Leeds LS2 9LU.
