PSAT048 Management of a Unilateral Testicular Tumor in a Patient with Congenital Adrenal Hyperplasia – Malignancy or Testicular Adrenal Rest Tumor?

Male patients with Congenital Adrenal Hyperplasia (CAH) are at risk of developing testicular adrenal rest tumors (TART). Late presentations are rare and often misdiagnosed as primary testicular germ cell tumors or other more common benign testicular lesions. We describe the case of a patient with CAH and a unilateral testicular tumor with regression in size after initiation of dexamethasone. A 24-year-old male with salt-wasting form of 21-hydroxylase deficiency underwent testicular U/S for evaluation of TART. While aware of a painless firm nodule on the latero-posterior aspect of his left testicle, his main concern was new onset infertility as he had conceived previously. He denied personal or family history of malignancy. Testicular U/S showed a 1.1×0.7×0.8 cm ill-defined, heterogeneously hypoechoic lesion with scattered calcifications and internal vascularity. He was referred to urology to undergo evaluation for possible for testicular cancer. CT abdomen/pelvis showed no evidence of metastatic disease. AFP was less than 2.5 ng/mL (reference range < 9.0 ng/mL), hCG was less than 1.0 mIU/mL (reference range<5.0 mIU/mL), and LDH was 221 U/L (reference range 140-271 U/L). The patient declined surgical intervention at this point and requested medical management. After discussion with the patient, we opted to trial dexamethasone to help suppress the nocturnal surge of ACTH in addition to his physiological dose of prednisone and fludrocortisone for CAH. He was started on 0.25 mg of dexamethasone followed closely with serial imaging and labs. Prior to initiation of dexamethasone, ACTH was 90.3 pg/mL (reference range 7.2–63.3 pg/mL). Two months after initiation of dexamethasone, ACTH decreased to 10.0 pg/mL. LH after initiation of dexamethasone was 8.58 mIU/mL (reference range 1.24–8.62 mIU/mL), FSH was 11.90 (reference range 1.27–19.26 mIU/mL), and testosterone level was 177 ng/dL (reference range 259-818 ng/dL). Testicular U/S six months after starting dexamethasone showed a 50% reduction in size of the heterogeneous hypoechoic left testicular lesion measuring 0.5×0.5×0.4 cm consistent with TART. However, he continued to have concerns regarding infertility, with work-up currently underway. TARTs are thought to arise from aberrant adrenal cells that may descend with the testes during embryogenesis. High ACTH levels in CAH due to lack of negative feedback can cause proliferation of these undifferentiated adrenal cells. Infertility is a predominant symptom due to local mass effect on the testes. Treatment of TART to prevent infertility requires elucidating an optimal steroid regimen that suppresses ACTH production, without suppression of LH and FSH. Moreover, most of the TARTs (around 80%) are bilateral and never malignant. Our patient's testicular tumor poses a diagnostic challenge given the late and atypical presentation of a unilateral tumor. The response to dexamethasone is very reassuring but continued surveillance is warranted. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.