Sertoli cell tumor/mixed germ cell-stromal cell tumor as separate neoplasms in a bilaterally cryptorchid dog.

An 11-year-old miniature poodle dog was presented with bilateral flank alopecia, gynecomastia, severe thrombocytopenia, and preputial edema. Based on characteristic clinical and hematological findings of hyperestrogenism and the presence of a caudal abdominal mass, a Sertoli cell tumor (SCT) was diagnosed. After a platelet concentrate transfusion, the SCT was surgically removed in addition to an atrophied contralateral testicle containing a mixed germ cell-stromal cell tumor. Recovery was uneventful. This combination of different neoplasms in separate testicles has yet to be documented. Key clinical message: This case of a SCT/mixed germ cell-stromal cell tumor combination in a bilaterally abdominal cryptorchid dog highlights common clinical signs associated with hyperestrogenism and the management of estrogen-induced myelotoxicity causing severe thrombocytopenia.