Aberrant Epididymal Tissue: A Significant Clinical Entity

0022-534 7/87 /1385-124 7$02.00/0 Vol. 138, November

THE JOURNAL OF UROLOGY

Printed in U.S.A.

Copyright © 1987 by The Williams & Wilkins Co.

ABERRANT EPIDIDYMAL TISSUE: A SIGNIFICANT CLINICAL ENTITY MICHAEL WOLLIN, FRAY F. MARSHALL, MITCHELL P. FINK, RAJWANT MALHOTRA DAVID A. DIAMOND

AND

From the Division of Urologic and Transplantation Surgery, The University of Massachusetts Medical Center, Worcester, Massachusetts, and The James Buchanan Brady Urological Institute, The Johns Hopkins Hospital, Baltimore, Maryland

ABSTRACT

Epididymal anomalies are relatively rare and usually they are associated with an undescended testis. A 33 to 66 per cent incidence of epididymal anomalies has been noted in male subjects with cryptorchidism. An increased incidence of epididymal anomalies also has been noted in association with cystic fibrosis, von Hippel-Lindau's syndrome and in male offspring of women treated with diethylstilbestrol. The frequency and anatomical spectrum of epididymal anomalies among men with normal descended testes are not known. We describe 3 patients with bilaterally descended testes, who were found to have aberrant epididymal tissue at scrotal or inguinal exploration. The variable presentations of aberrant epididymal tissue in these 3 patients can be explained best by understanding the embryology and anatomy of the epididymis and its associated vestigial structures. In all likelihood the structures encountered in our patients were the ductus aberrans inferior and the paradidymis. These structures, which rarely are included in urological anatomical descriptions of the epididymis, can be significant clinically. Therefore, it is important that the urologist be aware of their existence and their means of presentation. (J. Ural., 138: 1247-1250, 1987) Epididymal anomalies are thought to be relatively rare and usually they are associated with an undescended testis. We present 3 patients with bilaterally descended testes who were found to have aberrant epididymal tissue at scrotal or inguinal

largement and pain ensued during the next 4 days and surgery was performed. At exploration a normal left testis was found in association with an anatomically abnormal epididymis (fig. 1, A). The

Caputof epididymis

B FIG. 1. Case 1. A, 2 X 3 cm. cystic structure adherent to epididymal remnant at lower pole of testis. B, schematic highlights aberrant epididymal tissue and adherent cystic structure.

exploration. In 1 case the aberrant epididymal tissue was the cause of scrotal pain and in the 2 other cases it was an incidental finding that had potential clinical and medico legal implications. CASE REPORTS

Case 1. A 16-year-old white boy had acute left scrotal swelling and pain. There was no history of recent trauma. Physical examination revealed a 2 X 2 cm. mass in the left hemiscrotum, which was posterior to the testis and-transmitted light easily. No hernia was apparent nor was there cord thickening or tenderness. Ultrasound delineated a smooth, cystic area independent of the testis and epididymis. Progressive scrotal enAccepted for publication April 21, 1987.

epididymis appeared to be shortened, with the vas deferens exiting from the corpus epididymis. No cauda epididymis was apparent. A 2 x 3 cm. cystic structure was adherent to an epididymal remnant at the lower pole of the testis (fig. 1, B). Neither the cyst nor the epididymal remnant was in continuity with the vas and epididymis proper. The cyst a,nd epididymal remnant were resected. The cyst fluid contained no spermatazoa and culture was negative. Histological examination of the cyst lining demonstrated ciliated columnar epithelium that was consistent with epididymis (fig. 2). The scrotal pain resolved postoperatively. Case 2. A 31-year old white man underwent epididymovasostomy 4 years after vasectomy. On physical examination palpation of both testes and epididymides was normal. At operation

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0

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WOLLIN AND ASSOCIATES DISCUSSION

FIG. 2. Case 1. Histology of cyst lining demonstrates ciliated columnar epithelium consistent with epididymis. Reduced from X50.

FIG. 3. Case 2. Accessory epididymal tissue originating at epididymovasal junction, right epididymis (black arrows) and accessory epididymal tissue (white arrow). Loop is around vas deferens.

FIG. 4. Case 3. Histology demonstrates close proximity of epididymal tubules (large arrow) to hernia sac (small arrows). Reduced from

Congenital anomalie:s of the epididymis have received relatively little attention in the urological literature. Beginning with the earliest report of abnormal epididymal anatomy in 1851, 1 these anomalies have been thought to occur with greatest frequency in association with cryptorchid testes. 2- 4 In 1979 Marshall and Shermeta noted a 36 per cent incidence of epididymal anomalies among 42 undescended testes. 3 They classified these anomalies into 3 major groups: a looping, elongated epididymis, atresia of the epididymal head, body or tail, or agenesis of the epididymis. Mininberg and Schlossberg noted a 66 per cent incidence of epididymal abnormalities in association with 70 undescended testes studied intraoperatively. 4 The anomalies included uncoiling or looping of the epididymis and detachment of the epididymis from the testis. No cases of atresia were found in their series. Given the potential role of the epididymis in testicular descent, 4 - 6 it seems reasonable to anticipate a higher incidence of epididymal anomalies associated with cryptorchid testes. An increased incidence of epididymal anomalies has been noted in other clinical settings as well. Male subjects with cystic fibrosis have an increased incidence of epididymal atresia and agenesis. 7 •8 The etiology of these lesions, which are present at birth, remains unclear. They may be related functionally to abnormally viscous epididymal secretions during gestation, which result in ductal obstruction, or they may be owing to a genetic abnormality. 8 •9 Epididymal cysts usually involving the caput are seen in 13 to 20 per cent among male offspring of women treated with diethylstilbestrol during pregnancy. 9- 11 We do not have a clear explanation for this relationship. Epididymal cysts also are noted with greater frequency among patients with von Hippel-Lindau's disease. 12 The frequency and anatomical spectrum of epididymal anomalies among men with normally descended testes are not known and may simply reflect the inaccessibility of such epididymides for study. To assess the incidence of aberrant epididymal tissue in association with descended testes we have undertaken a cadaver study that will be reported in the future. The finding of aberrant epididymal tissue has not been discussed in-depth in the urological literature. In 1949 Michelson described 2 infertile men with normal bilaterally descended testes who were found at operation to have aberrant epididymides and absent vasa bilaterally. 13 In both cases there was bilateral absence of the cauda epididymis. Aberrant epididymal tissue has become clinically apparent in 3 cases of torsion of the ductus deferens, which presents as an acute scrotum that may be indistinguishable from testicular torsion. 14- 16 A review of epididymal embryology and anatomy has been helpful to clarify the clinical finding of aberrant epididymal tissue in our 3 patients, each of whom had bilaterally descended testes and normal vasa. As the mesonephros degenerates in a caudal direction some tubules retain their connection with the

X500. Appendix of epididym1s

proximal dissection to the epididymis on 1 side demonstrated an accessory epididymal structure, suggestive of epididymal duplication with branching at the epididymovasal junction (fig. 3). A normal epididymis was noted on the contralateral side. Case 3. An 18-year-old white man presented with the chief complaint of left scrotal swelling 2 weeks in duration. On physical examination an easily reducible indirect left inguinal hernia was noted as well as a normal, descended left testis and epididymis. At inguinal exploration an indirect hernia sac was demonstrated, which was free of viscera. The hernia sac was resected after careful dissection from the cord structures and high ligation. Histological examination demonstrated epididymal tissue associated with the hernia sac (fig. 4). Examination 1 month postoperatively demonstrated an entirely normal left testis and epididymis.

/

Mesonephric

Ouctus aberrans sup

Caput of epididymis 0 Me~oun ~phcic

···~

(! . ·. ~

tubule

· ...~ .· · ·· . .· O · · ·

tr,~ ~

::

Mesonephcos

Paramesonephric ~ . • . · ·

duct

l

U ndifferent1ated

aberrans inf.

gonad vesicle

Cauda of epid1dyrnis

FIG. 5. Fate of mesonephric tubules and mesonephric duct in male subject. Reprinted with permission from Clinical Embryology for Medical Students, 3rd ed. Edited by R. S. Snell. Boston: Little, Brown & Co., 1983.

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ABERRANT EPIDIDYMAL TISSUE

Tunica tiaoinalis Tunica albuoinea Its septa ./

">.--~. ...

.

·~ -. -~ FIG. 6. Vertical section of testis shows arrangements of ducts. Ductus aberrans inferior can be seen communicating with epididymovasal junction. Reprinted with permission from Gray's Anatomy, 30th ed. Edited by C. D. Clemente. Philadelphia: Lea & Febiger, 1985.

Paradidymis • Organ of Giraldes

Appendix epididymis

Appendix testis

aberrans of Haller FIG. 7. Classification and location of testicular appendages. Reprinted with permission from Rolnick, D., Kawanoue, S., Szanto, P. and Bush, I. M.: J. Urol., 100: 755, 1968.

mesonephric duct and arrange themselves into an upper and lower group. The upper group of tubules is brought into contact with the hilus of the testis where it ultimately communicates with the rete testis. The cranial end of the mesonephric duct develops into the corpus and cauda epididymis and vas. The lower group of mesonephric tubules becomes vestigial in both sexes and in the male subject it remains as the appendix epididymis, the ductus aberrans inferior and superior, and the paradidymis (fig. 5). These vestigial structures may develop into clinically detectable cysts that are associated with the epididymis.

The fully developed epididymis is a tortuous canal that measures 4 to 6 m. in length when uncoiled. It consists of a head or caput superiorly, a body or corpus centrally and an inferior tail or cauda. The caput and cauda are connected directly with the testis. The caput is attached to the superior testicular pole by the efferent tubules, and the cauda is attached to the inferior testicular pole by areolar tissue and tunica vaginalis. Occasionally, a tortuous ductule is seen communicating with the epididymal tail or epididymovasal junction (fig. 6). This ductule, known as the ductus aberrans inferior of Haller, is noted in certain anatomical texts17 but it is rarely found within anatomical descriptions of the epididymis in the urological literature. The ductus aberrans inferior may vary in length from 3.5 to 35 cm. when uncoiled. At times this structure may be free of communication from the epididymis or vas. A similar ductule, the ductus aberrans superior, may be seen attached to the epididymal head, communicating with the rete testis or to the epididymal body (fig. 7). Taking into consideration the anatomy of vestigial epididymal structures, one can explain the aberrant epididymal tissue noted in our 3 cases. The epididymal cyst in case 1 between the lower pole of the testis and the epididymovasal junction probably represented a markedly enlarged, blind-ending ductus aberrans inferior that lacked communication with the epididymis and vas proper. The acute increase in size of this cystic structure may be explained by the hormonal regulation of the epididymis. Epididymal functions that include the maturation, transport and storage of sperm are influenced by secretions from within the tubular lumen. These secretions occur in response to elevated dihydrotestosterone levels that increase linearly during puberty. Therefore, it would not seem unreasonable for a blind-ending epididymal remnant, as in case 1, to become engorged with secretions resulting from the elevation of dihydrotestosterone during puberty. The Y-type epididymal duplication noted during the epididymovasostomy in case 2 almost certainly represented the ductus aberrans inferior. The aberrant epididymis originated at the epididymovasal junction, as does the ductus aberrans and it was an appropriate size (3.5 cm.) for that structure. The epididymal tissue noted in association with the hernia sac in case 3 conceivably could have arisen from either of 2 vestigial epididymal structures. The paradidymis, which is located in the cord opposite the head of the epididymis, could have been in close proximity to a long indirect hernia sac. On the other hand, an uncoiled ductus aberrans, which can be up to 35 cm. long, also could have been associated with a hernia sac within the spermatic cord. These 3 cases illustrate the variable presentation of aberrant epididymal tissue, much of which may be explained by our knowledge of the vestigial structures of the epididymis. It seems important to recognize that such epididymal tissue may account for symptoms, as in case 1. In addition, it may be encountered at epididymovasostomy, which could confuse the urologist who is unaware of this anatomical entity. Finally, as in case 3, the histological recognition of aberrant epididymal tissue may appear to represent a complication of herniorrhaphy when such is not the case and, therefore, it may have important medicolegal implications.

REFERENCES

Dean, A. L., Jr., Major, J. W. and Ottenheimer, E. J.: Failure of fusion of the testis and epididymis. J. Urol., 68: 754, 1952. 2. Scorer, C. G. and Farrington, G. H.: Congenital anomalies of the testis: cryptorchidism, testicular torsion and inguinal hernia and hydrocele. In: Campbell's Urology, 4th ed. Edited by J. H. Harrison, R. F. Gittes, A. D. Perlmutter, T. A. Stamey and P. C. Walsh. Philadelphia: W. B. Saunders Co., vol. 2, sect. XII, chapt. 44,pp. 1549-1565, 1979. 3. Marshall, F. F. and Shermeta, D. W.: Epididymal abnormalities associated with undescended testis. J. Urol., 121: 341, 1979. 1.

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4. Mininberg, D. T. and Schlossberg, S.: The role of the epididymis in testicular descent. J. Urol., 129: 1207, 1983. 5. Bedford, J. M.: Anatomical evidence for the epididymis as the prime mover in the evolution of the scrotum. Amer. J. Anat., 152: 483, 1978. 6. Hadziselimovic, F. and Kruslin, E.: The role of the epididymis in descensus testis and the topographical relationship between the testis and epididymis from the sixth month of pregnancy until immediately after birth. Anat. Embryol., 155: 191, 1979. 7. Holschaw, D. S., Perlmutter, A. D., Jockin, H. and Shwachman, H.: Genital abnormalities in male patients with cystic fibrosis. J. Urol., 106: 568, 1971. 8. Landing, B. H., Wells, T. R. and Wong, C.-I.: Abnormality of the epididymis and vas deferens in cystic fibrosis. Arch. Path., 88: 569, 1969. 9. Bibbo, M., Al-Negeeb, M., Baccarini, I., Gill, W., Newton, M., Sleeper, K. M., Sonek, M. and Wied, G.: Follow-up study of male and female offspring of DES-treated mothers. A preliminary report. J. Reprod. Med., 15: 29, 1975. 10. Cosgrove, M. D., Benton, B. and Henderson, B. E.: Male genitourinary abnormalities and maternal diethylstilbestrol. J. Urol.,

117: 220, 1977. 11. Whitehead, E. D. and Leiter, E.: Genital abnormalities and abnormal semen analyses in male patients exposed to diethylstilbestrol in utero. J. Urol., 125: 47, 1981. 12. Bernstein, J. and Gardiner, K. D., Jr.: Renal cystic disease and renal dysplasia. In: Campbell's Urology, 5th ed. Edited by P. C. Walsh, R. F. Gittes, A. D. Perlmutter and T. A. Stamey. Philadelphia: W. B. Saunders Co., vol. 2, sect. XII, chapt. 39, pp. 1760-1803, 1986. 13. Michelson, L.: Congenital anomalies of the ductus deferens and epididymis. J. Urol., 61: 384, 1949. 14. Ballesteros Sampo!, J. J., Munne, A. and Bosch, A.: A vas aberrans torsion. Brit. J. Urol., 58: 97, 1986. 15. Randall, A.: Torsion of the appendix testis (hydatid of Morgagni). J. Urol., 41: 715, 1939. 16. Skoglund, R. W., McRoberts, J. W. and Ragde, H.: Torsion of testicular appendages: presentation of 43 new cases and a collective review. J. Urol., 104: 598, 1970. 17. Gray, H.: The urogenital system. In: Anatomy of the Human Body, 29th ed. Edited by C. M. Goss. Philadelphia: Lea & Febiger, chapt. 17,pp. 1265-1339, 1973.