Rama Chandran Suresh, Tan Yongcheng Benjamin
Department of Endocrinology, Singapore General Hospital, Singapore 169608, Singapore.
Department of Anatomical Pathology, Division of Pathology, Singapore General Hospital, Singapore 169608, Singapore.
JCEM Case Rep. 2025 Jul 17;3(9):luaf158. doi: 10.1210/jcemcr/luaf158. eCollection 2025 Sep.
Ectopic expression of PTH in nonmetastatic prostate cancer is a rare occurrence. We present a case of a 60-year-old Chinese man who initially presented with hyperparathyroidism, PTH 80.1 pg/mL (SI: 8.5 pmol/L) (reference range, 8.5-58.5 pg/mL [SI: 0.9-6.2 pmol/L]), hypophosphatemia, 1.95 mg/dL (SI: 0.63 mmol/L) (reference range, 2.91-4.64 mg/dL [SI: 0.94-1.5 mmol/L]) and normal calcium levels, 2.27 mmol/L (SI 9.08 mg/dL) (reference range, 2.1-2.6 mmol/L [SI: 8.4-10.4 mg/dL]). Two years later, he was diagnosed with prostate adenocarcinoma. A whole-body bone scan ruled out osteoblastic metastases. Notably, the patient exhibited elevated urinary calcium excretion, 304.6 mg/day (SI: 7.6 mmol/day) (reference range, 33.2-272.6 mg/day [SI: 0.82-6.74 mmol/day]) and indeterminate urinary fractional calcium excretion (1.79%). A Technetium-99 sestamibi scan did not identify any hyperfunctioning parathyroid adenoma. Following treatment for prostate cancer, both hyperparathyroidism and hypophosphatemia resolved. Immunostaining of prostate cancer tissue revealed ectopic PTH expression. This case highlights a rare cause of hyperparathyroidism due to ectopic PTH secretion in prostate cancer, adding to known etiologies such as osteoblastic metastases, vitamin D deficiency, oncogenic osteomalacia, renal insufficiency, and primary hyperparathyroidism. Recognizing ectopic PTH expression is crucial for managing prostate cancer patients presenting with hyperparathyroidism.
甲状旁腺激素（PTH）在非转移性前列腺癌中的异位表达极为罕见。我们报告一例60岁中国男性病例，该患者最初表现为甲状旁腺功能亢进，PTH为80.1 pg/mL（国际单位：8.5 pmol/L）（参考范围为8.5 - 58.5 pg/mL [国际单位：0.9 - 6.2 pmol/L]），低磷血症，血磷1.95 mg/dL（国际单位：0.63 mmol/L）（参考范围为2.91 - 4.64 mg/dL [国际单位：0.94 - 1.5 mmol/L]），血钙水平正常，为2.27 mmol/L（国际单位9.08 mg/dL）（参考范围为2.1 - 2.6 mmol/L [国际单位：8.4 - 10.4 mg/dL]）。两年后，他被诊断为前列腺腺癌。全身骨扫描排除了成骨性转移。值得注意的是，该患者尿钙排泄量升高，为304.6 mg/天（国际单位：7.6 mmol/天）（参考范围为33.2 - 272.6 mg/天 [国际单位：0.82 - 6.74 mmol/天]），尿钙分数排泄率不确定（1.79%）。锝-99甲氧基异丁基异腈扫描未发现任何功能亢进的甲状旁腺腺瘤。前列腺癌治疗后，甲状旁腺功能亢进和低磷血症均得到缓解。前列腺癌组织免疫染色显示有异位PTH表达。该病例突出了前列腺癌中异位PTH分泌导致甲状旁腺功能亢进这一罕见病因，丰富了已知病因，如成骨性转移、维生素D缺乏、肿瘤性骨软化症、肾功能不全和原发性甲状旁腺功能亢进。认识到异位PTH表达对于管理伴有甲状旁腺功能亢进的前列腺癌患者至关重要。
