Hypercalcemia in upper urinary tract urothelial carcinoma: a case report and literature review

Hypercalcemia and Renal Mass: A Diagnostically Challenging Case

Hypercalcemia of malignancy frequently occurs in patients with solid tumors as a paraneoplastic syndrome known as humoral hypercalcemia of malignancy (HHM), caused by the secretion of parathyroid hormone-related peptide (PTHrP). On the other hand, 1,25-dihydroxyvitamin D [1,25(OH)2D]-mediated hypercalcemia is a less common cause of hypercalcemia of malignancy and is mostly observed in lymphoma patients. Here, we report an interesting case of a 77-year-old male nursing home resident with suspected renal cell carcinoma (RCC) presenting with severe hypercalcemia (18.7 mg/dL), which was initially presumed to be HHM. However, workup revealed nonsuppressed parathyroid hormone, low PTHrP, and elevated 25-hydroxyvitamin D and 1,25(OH)2D levels. Steroids were initiated due to an inadequate response to bisphosphonate therapy and elevated vitamin D metabolites, resulting in further reduction in serum calcium levels. This case highlights the need to consider multiple concurrent etiologies in the differential diagnosis of severe hypercalcemia, including the possible role of calcitriol-mediated hypercalcemia in RCC.

Hypercalcemia an exceptional complication in upper urinary tract urothelial carcinoma

Tumors of the upper urinary tract are discovered, either by clinical symptomatology or as part of the evaluation of a bladder tumor. Hypercalcemia is one of the most common paraneoplastic syndromes and an exceptional complication of urothelial carcinoma of the upper tract. Several physiopathological mechanisms have been proposed to explain this rare and serious complication. Hypercalcemia is often correlated with tumors with a poor prognosis.

Relevance of concurrent hypercalcemia in ureteric sarcoidosis complicated with bladder urothelial carcinoma: a case report

BACKGROUND

Sarcoidosis is a multisystem inflammatory disorder and can affect any organ; however, ureteric involvement is extremely rare with only four cases reported in the literature to date, all of which were diagnosed with surgical ureteral resection including a nephroureterectomy. This study reports the first case of ureteric sarcoidosis controlled with medical therapy where a differential diagnosis was performed based on the diagnostic clue of hypercalcemia. A definitive diagnosis was established without surgical resection of the ureter.

CASE PRESENTATION

A 60-year-old man presented with anorexia and weight loss. Blood tests showed renal dysfunction and hypercalcemia. Computed tomography revealed left hydronephrosis associated with left lower ureteral wall thickening, which showed high signal intensity on diffusion-weighted magnetic resonance imaging. Similarly, we detected a bladder tumor on cystoscopy, and a 2-cm-long stenosis was revealed by retrograde ureterography; therefore, ureteral cancer was suspected. Meanwhile, considering the clinical implication of hypercalcemia, a differential diagnosis of sarcoidosis was established based on elevated levels of sarcoidosis markers. Fluorodeoxyglucose positron emission tomography showed fluorodeoxyglucose accumulation in the left lower ureter, skin, and muscles, suggestive of ureteric sarcoidosis with systemic sarcoid nodules. For a definitive diagnosis, transurethral resection of the bladder tumor and ureteroscopic biopsy were performed. Histopathological examination revealed ureteric sarcoidosis with bladder urothelial carcinoma. Following an oral administration of prednisolone, hypercalcemia instantly resolved, the renal function immediately improved, and the left ureteral lesion showed complete resolution with no recurrence.

CONCLUSIONS

In this case, the co-occurrence of ureteral lesion with bladder tumor evoked a diagnosis of ureteral cancer. However, considering a case of ureteral lesion complicated with hypercalcemia, assessment for differential diagnosis was performed based on the calcium metabolism and sarcoidosis markers. In cases of suspected ureteric sarcoidosis from the assessment, pathological evaluation with ureteroscopic biopsy should be performed to avoid nephroureterectomy.