Crouching tiger, hidden dragon.

A 34-year-old man presented with a history of bilaterally undescended testes since birth. A bilateral orchidectomy was performed. Macroscopic examination of the specimen demonstrated multiple pale nodules within both testes, the largest of which measured 3 mm in diameter.Review the high-quality, interactive digital Aperio slide at http://virtualacp.com/JCPCases/jclinpath-2017-204691/ and consider your diagnosis.1. Germ cell neoplasia in situ (GCNIS)2. Leydig cell hyperplasia3. Seminoma4. Sertoli cell nodule5. Sertoli cell tumourThe submitted section demonstrates features of cryptorchidism, with marked hyalinisation of the tubular basement membrane, germ cell atrophy and Leydig cell hyperplasia (figure 1A,B). Most of the seminiferous tubules are lined only by Sertoli cells. However, there are also multiple small nodular aggregates of Sertoli cells that correspond to the macroscopically described abnormality (figure 1A,C,D). These have been occasionally referred to by the misnomer ‘Pick’s Adenomas’ but have been shown to be polyclonal and best referred to as Sertoli cell nodules.Figure 1 The testis (A) shows germ cell atrophy with basement membrane thickening and Leydig cell hyperplasia in keeping with cryptorchidism (B) as well as Sertoli cell nodules (C,D). (A–D: Hu0026E).On low-power examination some of the atrophic tubules contain peripherally located cells with clear cytoplasm that on closer examination show cytological atypia with prominent nucleoli (figure 2). This represents in situ malignancy that has been referred to as ‘carcinoma in situ’ or ‘intratubular germ cell neoplasia’. However, these cells are germ cells rather …