From persistent hypercalcemia to parathyroid carcinoma: a case report of acute urinary retention and the diagnostic role of Ki-67

Background Parathyroid carcinoma (PC) is a rare and often misdiagnosed endocrine malignancy that can present with diverse clinical manifestations, complicating its detection and management. Case presentation This case report presents a 59-year-old male diagnosed with parathyroid carcinoma (PC), initially misidentified as benign parathyroid hyperplasia and adenoma. Over the course of 4 years, the patient underwent three surgical interventions. Final surgery confirmed the definitive diagnosis of PC, which revealed vascular invasion. The patient exhibited unusual clinical manifestations, notably severe hypercalcemia leading to acute urinary retention (AUR), which posed a diagnostic challenge. Pathological evaluation indicated a Ki-67 proliferation index of 8%, raising concerns about malignancy. This case highlights the need for multidisciplinary collaboration in the diagnostic process, recognizing atypical symptoms and carefully interpreting histopathological markers in suspected PC cases. Conclusion Persistent hyperparathyroidism, elevated Ki-67 levels, and unexplained lower urinary tract symptoms (LUTS) should prompt re-evaluation for malignancy, highlighting the rarity yet clinical significance of hypercalcemia-induced AUR as a presenting symptom of underlying parathyroid pathology.