PENILE TUMOR WITH RENAL METASTASIS ASSOCIATED WITH GIANT STAGHORN CALCULUS: CASE REPORT

Renal tumors are urogenital neoplasms classified according to their morphology. The latest revision, carried out by the World Health Organization in 2022, divides these tumors into renal, metanephric, mixed, mesenchymal, embryonic, and germ cell (MOCH et al, 2022). Among these, renal cell carcinomas represent about 85% of primary renal neoplasms, being associated with smoking, obesity, hypertension, and kidney stones (CHEUNGPASITPORN et al., 2015; ATKINS et al., 2022). The presence of renal tumors secondary to metastatic implants from other sites is relatively rare in the literature (PATEL, 2011). 

Penile cancer is a rare tumor in western countries, with Brazil being one of the countries with the highest incidence of this neoplasia in the world (FAVORITO et al., 2008). The presence of phimosis, urinary infections, penile lesions and warts, HPV and HIV infection, obesity, and smoking, in addition to the type of sexual practice are risk factors for the disease (PETTAWAY, 2023). Squamous cell carcinoma accounts for approximately 95% of these malignant neoplasms (IORGA et al., 2020), with the sarcomatoid subtype being a rare, aggressive variant associated with distant metastases (PETTAWAY, 2023).

Nephrolithiasis is a common condition in emergency services, affecting 5% of the general population. The incidence is influenced by several factors, such as geographic region, age, and ethnicity, being more common in Caucasians, with no differentiation between sexes (CURHUN, 2022). On average, over a lifetime, there is an 8-10% risk of urinary stones, with a peak incidence in middle-aged patients. Nephrolithiasis is characterized by the saturation and precipitation of crystals in the nephrons, resulting in solid intratubular calculi, with structural and functional renal impairment. Several factors influence the formation of calculi, such as urinary volume, solute concentration, and imbalance between inhibitors (citrate, pyrophosphate, and urinary glycoproteins) and promoters (hypercalciuria, hyperuricosuria, hyperoxaluria, and hypocitraturia) of lithogenesis, with calcium-based calculi being the most common (PARSELL, 2016). 

 The present study aims to report a clinical-surgical case of an extensive staghorn calculus in a context of penile neoplasia with renal metastasis.

Data information was obtained through medical record review and literature review. 

A 64-year-old male patient is described, hypertensive, smoker since he was 10 years old, former alcoholic, with gout, recurrent urinary infections with multiple nephrotic colic since youth, previous penile tumor with report of treatment 8 years previously. The patient was admitted to the emergency department due to bilateral flank pain, intensity 8/10, irradiation to the abdomen, oliguria, vomiting, lack of appetite and associated dysuria. He reported important weight loss in the last year, approximately 15 kg in the last month. The patient denied hematuria or previous diagnosis of kidney disease. On physical examination, he was emaciated, with palpable cervical and inguinal lymph nodes, painless, systolic aortic murmur 2+/6+, diffuse abdominal pain on deep palpation, with a palpable mass on the right flank. In the initial investigation, computed tomography of the abdomen and pelvis showed extensive staghorn calculus and significant bilateral hydronephrosis, in addition to multiple lymph nodes with signs of necrosis (Figures 1 and 2). Initial laboratory tests showed renal dysfunction, normochromic normocytic anemia, hyperuricemia, hypercalcemia with secondary hypoparathyroidism, and elevated LDH (Table 1). Serum protein electrophoresis suggested a monoclonal band in the gamma-globulin region, which was not confirmed with immunofixation.  Due to renal dysfunction in the presence of hydronephrosis, the patient underwent insertion of a bilateral double-J catheter to unblock the urinary tract, with partial improvement in renal function. Ten days later, he underwent open right pyelolithotomy to remove a staghorn stone, with intraoperative evidence of a renal mass on the right. An incisional biopsy of the renal tumor was performed, as well as a biopsy of the retroperitoneal lymph nodes, with the creation of a nephrostomy on the right and drainage of the adjacent purulent collection. During hospitalization, he evolved with infectious complications related to the procedure, with multiple cycles of antimicrobials (Meropenem, Amikacin, Fluconazole). An attempt was made to control calcemia with hydration and diuretics, without success, requiring a one-off dose of pamidronate. The patient evolved with improvement in renal function, normocalcemia, and resolution of the infectious process, without the need for hemodialysis during hospitalization. The anatomopathological analysis of renal tissue showed signs of poorly differentiated malignant neoplasm, with intense nuclear atypia, high mitotic index and necrosis. Lymph node analysis demonstrated lymph node metastasis, associated with necrosis, fibrosis, acute inflammatory infiltrate, and angiolymphatic invasion. Immunohistochemistry documented the tumor as a poorly differentiated squamous cell carcinoma of the sarcomatoid variant. Hormonal evaluation showed increased CEA, with elevated beta-hCG levels. Due to clinical stability, the patient was discharged with stable renal function and an oncological referral to a reference center in Londrina.

This report describes a case of hypercalcemia of malignancy associated with a poorly differentiated penile sarcomatoid squamous cell carcinoma, with renal metastasis and lymph node invasion. A large staghorn calculus, palpable on physical examination, with associated urinary obstruction, demonstrates the severity of the underlying disease, already well advanced. The patient had a report of a lesion on the glans penis treated approximately 8 years previously, diagnosed as penile cancer based on the family description, however, there was no medical record or details of the approach, nor stratification of risk of metastasis at the time of diagnosis, much less follow-up.  It was presumed that at the time the patient had localized disease (Tis, Ta, T1), given the resection of the lesion and topical treatment in the initial presentation of the neoplasm. Even with localized disease, follow-up and surveillance of disease recurrence is necessary, since recurrence in 39 months is 9% (PAGLIARO, 2023). Persistent smoking associated with recurrent urinary infections since youth were potential catalysts for the evolution of the neoplasm to lymph node invasion and secondary renal implantation. The progression of penile carcinoma to metastatic disease is rare, however it is associated with a poor prognosis and a median survival of 6 months. Among the sites of metastasis, renal implantation is also rare, representing about 10% of cases, being more common in the bladder and prostate (PETTAWAY, 2023). Hypercalcemia of malignancy is associated with several tumors, especially squamous cell tumors. When there is no evidence of osteolytic invasion, in the context of PTH suppression, the main mechanism is humoral. Mediated by parathyroid hormone-related protein (PTHrP), which mimics the action of parathyroid hormone on its receptor, there is induction of bone and renal calcium reabsorption, resulting in hypercalcemia (HORWITZ, 2023). The patient has a history of previous urinary calculi, that is, he already had a predisposition to lithogenesis, which was intensified with hypercalcemia and recurrent urinary infections, and potentiated the formation of giant renal calcium calculi. It was not possible to measure (PTHrP) and calcitriol, as these tests are not available in the service. Due to renal dysfunction with hydronephrosis and extensive calculi, the diversion of the urinary tract allowed improvement in renal function, with calcemic control being obtained with one-off pamidronate. In view of the risk of recurrence and potential evolution to a severe and disseminated pathology, the need for adequate follow-up of the treated disease is evident, in order to avoid outcomes of the magnitude of the case, with multiple associated complications.