HCG and measurement of their subunits

The classification of the cysts which I presented does not represent a simplistic classification based solely on content of spermatozoa. The classification included the work of Elder and Mostwin’ who established the diagnosis of ejaculatory duct-urogenital sinus cyst. The location of the cyst in the midline, the size of the cyst, the presence of a septum in the cyst, and the fact that the cyst is intraprostatic or cephalad to the prostate gland and in the retrovesical location all contribute 1.0 the classification of these cysts. Extremely large (8-9 cm) retrovesical midline cysts cephalad to the prostate gland, probably represent urogenital sinus-ejaculatory duct cysts. The size of these cysts in pediatric cases would be variable and spermatozoa would not be present in these cases. When these urogenital sinus-ejaculatory duct cysts actually begin and how long they take to develop to their large size when found in adults is also open to speculation. Miillerian duct cysts most likely do not achieve such a large size. The miillerian duct cyst which we reported as diagnosed by prostatic ultrasound did not communicate with the ejaculatory ducts. Our patient presented with obstructive symptoms and the cyst was drained through the ejaculatory duct, since this would be the least traumatic method to drain this lesion in a young male where an attempt to preserve fertility is mandatory. There also is considerable thinning of the prostatic urethra and the verumontanum overlying the cyst in these patients, making this method of drainage effective. Our patient is still producing spermatozoa, and there is no evidence of recurrence of the miillerian duct cyst. I am sure that the evaluation of the second case of the urogenital sinus-ejaculatory duct cyst which I reported will satisfy the criteria for reporting these cysts (Fig. 1). J. S. Mayersak, M.D. Urology

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ua mto mullerian duct cyst. J Pedlatr Surg 27: 761, IYU2 4. Thurnher S, Hricak H, and Tanagho IA Mullerlan duct cysr: diagnosis with MR imagtng. Radiology 168: 25, lY88. 5. Elder JS, and Mostwm JL: Cyst of thl: ciacrllator! duct/ urogenital sinus. J Ural 132: 768, 198-1

HCG and Measurement Their Subunits

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7-O J-HE FDJJOR: I would like to congratulate Waples and Messing for their excellent article concerning redo lymphadenectomy that appeared in the July issue (vol. 42, pages 31-34, 1993) of URI.ILO(;Y. I would like to bring attention to the fact that it is not only serum level of the beta-subunit of human chorionic gonadotropin (beta HCG) that is measured, as indicated by these authors. it is the serum level of the whole molecule that is measured and reported by the laboratory. In measuring the serum level of this marker, the whole molecule is detected by utilizing antibody against the beta-subunit, because the antibody against the whole molecule (I/3 alpha and 2/3 beta) will cross-react with a number of trophic hormones specially luteinizing hormone (LH). This is due to the fact that the amino acid sequence of the alpha subunits of the HCG and LH are essentially identical as reported by Vaitukaitis and coworkers.’ The specificity is only conferred by the significant differences in the amino acid sequence of their beta-subunits. Specifically the carboxyterminus of the beta-subunit contains a group of 30 amino acids not found in LH. It is important to realize that although antibody to the beta-subunit is utilized in radioimmunoassay, the reported serum level by various laboratories is the measurement of the whole molecule rather than only beta-subunit of the HCG as these authors have indicated. It is also well established that the measurement of the serum level of the intact molecule of serum HCG and alphafetoprotein have been helpful in monitoring patients with testicular cancer.’

REFERENCES 1. Mayersak JS: Urogenital sinus-ejaculatory duct cyst: a case reporr with a proposed clinical classification and review of the literature. J Urol 142: 1330, 1989. 2. Mayersak JS: Urogenital sinus-ejaculatory duct cyst: a case report with preoperative magnetic resonance imaging and computerized axial tomography imaging. A review of the literature and modification of clinical classification. Submitted for publication, Urology. 3. Takahashl M, Kaneko S, Ogawa I, Yamabe K. Tsukada H, and Ntshlda K: A case of ectopic opemng of vasa deferen-

N. Javadpour. M.D. Baltimort.,

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REFEREN(,ES I. Vaitukaitis JL, Braunstein GD. and Ros\ &T: A radioimmunoassay which specifically measures human chorionic gonadotropin in the presence of human lutcinlzing hermone. Am J Obstet Gynecol 113: 751-758. 1972 2. Javadpour N: The role of biologic tumor marhers in testicular cancer. Cancer 45: 1755-l 761. IWO.