Wilms tumor commonly presents as:
**Core Concept**
Wilms tumor, also known as nephroblastoma, is a type of cancer that originates in the kidneys. It is the most common type of childhood cancer affecting the kidney. The tumor typically arises from the embryonic cells that form the kidney during fetal development.
**Why the Correct Answer is Right**
Wilms tumor commonly presents as an abdominal mass, often incidentally detected by parents during bathing or dressing. This is because the tumor grows rapidly and can become quite large before causing any symptoms. In children, Wilms tumor typically presents before the age of 5 years. The mass may be palpable on abdominal examination, and imaging studies such as ultrasound or CT scans can confirm the diagnosis.
**Why Each Wrong Option is Incorrect**
**Option A:** This option may be tempting, but Wilms tumor does not typically present with abdominal pain. While pain can occur as the tumor grows, it is not a common initial presentation.
**Option B:** Although hematuria (blood in the urine) can occur in Wilms tumor, it is not the most common presentation. Hematuria may be seen as the tumor invades the renal pelvis or ureter.
**Option C:** Fever is not a common presenting symptom of Wilms tumor. While systemic symptoms such as fever can occur in advanced disease, they are not typical of the initial presentation.
**Clinical Pearl / High-Yield Fact**
Wilms tumor is often associated with congenital anomalies of the genitourinary tract, such as horseshoe kidney or polycystic kidney disease. A careful review of the patient's medical and family history is essential in identifying these risk factors.
**Correct Answer: A. An abdominal mass.**