Renal tuberculosis mimicking cystic renal cell carcinoma: A case report

Abstract

Renal tuberculosis is a rare and often under-recognized condition, frequently leading to delayed diagnosis due to its nonspecific symptoms and atypical clinical presentation. We report a case of renal tuberculosis initially masquerading as a renal cystic tumor in a 56-year-old woman. This case highlights the crucial importance of a thorough clinical and diagnostic approach to differentiate renal tuberculosis lesions from renal cystic tumors. Early and appropriate management of this condition can help avoid complications and improve patient prognosis.

1 Introduction

Renal tuberculosis is an uncommon manifestation of extrapulmonary tuberculosis, accounting for approximately 5 % of such cases. The high oxygen tension in the renal cortex favors renal localization. This condition is often overlooked due to its atypical clinical presentation, which can lead to diagnostic errors and delays in appropriate management. In this article, we present a rare case of renal tuberculosis initially misdiagnosed as a renal cystic tumor, highlighting the importance of a meticulous diagnostic approach.

2 Case presentation

A 54-year-old female patient, with multiple comorbidities, including diabetes, and hypertension, hospitalized for total hematuria evolving for 4 months, weight loss, decreased appetite, generalized weakness, and right lumbar pain without fever. Clinical examination reveals a BMI of 27 kg/m ² , mild right lumbar tenderness, and a palpable mass. The general examination found a blood pressure of 110/80 mmHg and a pulse of 84 bpm. The physical examination found a palpable mass in the right lumbar fossa, no varicocele, and no low limb edema. The urine cytobacteriological examination was negative. She had a hemoglobin level of 12 g/dl, a calcium level of 2.15 mmol/l, and a creatinine level of 8 mg/l. Abdominal computed tomography (CT) showed a well-defined 24 mm right mediorenal cyst with an irregular wall that enhanced after the injection of contrast material, along with thick, irregular calcifications classified as Bosniak 3 ( Fig. 1 ). The patient underwent an open radical right nephrectomy by lombotomy. No post-surgical complications were observed in the aftermath of the surgery. Histopathological analysis of the specimen revealed multiple confluent caseating granulomas accompanied by dense inflammatory areas extending into the perinephric fat, indicative of renal tuberculosis ( Fig. 2 ). The patient had received the Bacille Calmette-Guérin (BCG) vaccine during childhood. A tuberculin skin test revealed an induration of 14 mm, and ten urine samples were collected for mycobacterial culture along with bronchoalveolar lavage specimens. All cultures for mycobacteria returned negative results. However, a QuantiFERON-TB Gold test (Quest Diagnostics, Secaucus, NJ, USA) yielded a positive result. The patient was treated with antituberculosis medication for six months and remained in good health during a 48-month follow-up period.