A testicular tumor resembling the sex cord with annular tubules in a case of the androgen insensitivity syndrome.

Sex cord tumor with annular tubules (SCTAT) is a distinctive neoplasm with indifferent cells of sex cord derivation in a characteristic arrangement of ring-like tubules. Much attention has been drawn to its association with the Peutz-Jeghers syndrome (PJS) with reported occurrence of the tumor in the testis of a boy with PJS. The authors present two cases of the androgen insensitivity syndrome (AIS), one of the cases being distinctive in having a large multicystic tumor resembling the SCTAT in the immature gonad. Additionally, the focal areas of the tumor, the large Sertoli cells lining the tubules, resembled those of a large cell calcifying Sertoli cell tumor (LCCSCT) although no calcific areas were discernible. Although the occurrence of neoplasms like germinomas and tubular adenomas is well known in the AIS, SCTAT has hitherto not been reported in a gonad of the AIS. SCTAT has been placed under an "unclassified sex cord-stromal" category in the World Health Organization (WHO) Classification, yet, opinions are divided as to its origin from a granulosa or Sertoli cell, although an overlap in the histologic features of the two cell categories is to be anticipated in view of their homologous nature. In the case presented, the close resemblance of the tumor cells to the Sertoli cells of the uninvolved gonad would further support the concept of a Sertoli line of differentiation of the SCTAT.