Variation of gonadal dysgenesis and tumor risk in patients with 45,X/46,XY mosaicism
Fumi Matsumoto, M.D., Ph.D., Hiromu Noi, M.D., Satoko Matsuyama, M.D., Futoshi Matsui, M.D., Ph.D., Koji Yazawa, M.D., Ph.D..
Osaka Women's and Children's Hospital, Osaka, Japan.
<META NAME="author" CONTENT="松本 富美">
BACKGROUND - The 45,X/46,XY mosaic karyotype represents a wide spectrum of phenotypes, from Turner females to phenotypic males with varying degrees of genital ambiguity. Gonadal assessment is mandatory in patients with 45,X/46,XY mosaicism not only for the diagnosis of disorders of sex development (DSD) but also for the increased risk of gonadal tumors. The aim of this study was to present gonadal features of 45,X/46,XY mosaicism including a unique variant of dysgenetic testis.
METHODS - A retrospective review was conducted of 34 patients with 45,X/46,XY karyotype or its variant who had gonadal biopsy or gonadectomy in a single institute between 1996 and 2017. Twenty-four patients had ambiguous genitalia, 9 had unambiguous female genitalia, and one had male genitalia with a unilateral impalpable testis. Age at surgery ranged from 0 to 12 (median 0) years. Histology of 57 gonadal specimens was available.
RESULTS - Gross findings confirmed a dysgenetic testis on one side and a streak gonad on the other in 20 of 34 patients (59%), bilateral streak gonads in 9(26%), bilateral dysgenetic testes in 5 (15%). An association of streak gonad with dysgenetic testis on one side, i.e. a streak testis was observed in 7 gonads in 6 patients. All streak gonads were removed and bilateral gonadectomy was performed in 15 patients raised as a girl. Pathologic examination revealed gonadal tumors in 6 of 34 (18%) patients, including a gonadoblastoma in 7 gonads in 5 patients and an association of dysgerminoma with gonadoblastoma in one gonad. Imaging study showed no metastasis and postoperative course was uneventful in all patients but one boy. A seminoma was detected in his solitary testis originally located in the scrotum at the age of 16 years.
CONCLUSIONS - Patients with 45,X/46,XY mosaicism had dysgenetic gonads in great variety. Considering increased risk of gonadal tumor, early investigation and individual management including prophylactic gonadectomy are recommended.
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