A 26-year-old man arrived at the emergency department with a seven-day history of hematemesis and melena. He had no previous medical history and did not drink alcohol or used any illicit drug or medication.
Physical examination on admission showed blood pressure of 100/60 mmHg, a temperature of 36°C (96.8°F), a pulse rate of 90/min, and a respiratory rate of 22/min; his height was 1.75 m, weight 98 kg, and BMI 32 kg/m2. He experienced pain with deep palpation in the epigastrium and no organomegaly or lymphadenopathy was identified. The left scrotal sac was enlarged and indurated and there was a mass in the left scrotum that was indistinguishable from the left testis and provoked displacement of structures of the penis and right testis (the right scrotum was empty). No inguinal lymphadenopathy was identified.
Laboratory tests revealed normal liver function. Hemoglobin was 9.13 g/dl, MCV was 87.9 fL, WBC was 11.9 K/uL, neutrophils were 9.81 K/uL, lymphocyte count was 1.59 K/uL, and platelet level was 252 K/uL. Serum glucose level was 106 mg/dl, BUN was 38 mg/dl, creatinine was 0.9 mg/dl, and calcium was 8.9 mg/dl. Serum alpha-fetoprotein (AFP) level was 17,090 ng/mL, lactate dehydrogenase was 1480 U/L (normal range: 91–180 IU/L), and human chorionic gonadotropin level was 287.4 IU/mL.
After resuscitation with crystalloid solutions, he underwent upper endoscopy. The gastroenterologist found abundant active bleeding, for which orotracheal intubation was decided to provide airway protection. The patient was transferred to the intensive care unit. A second upper endoscopy revealed a type 1 isolated gastric varix, treated with cyanoacrylate without complications ().
A scrotal US showed a large heterogeneous image in the left testicle area, with an echogenic and cystic solid component and flow presence with color Doppler assessment.
A contrasted CT scan of the thorax, abdomen, and pelvis showed a liver of normal size and density with multiple retrocrural, retroperitoneal, mesenteric, and left iliac metastatic lymphadenopathy which caused extrinsic compression of the portal vein along with splenic vein partial thrombosis with left-sided portal hypertension and perigastric and perisplenic collateral neovascularization (). A heterogeneous, well defined mass was found in the left testicle, 16.7 × 16.1 × 14.9 cm, with a solid component that was enhanced with the administration of contrast, as well as a cystic component. There was also invasion of the left spermatic cord.
The patient was extubated after surveillance and transferred to the Internal Medicine Department. We started chemotherapy with etoposide 100 mg/m2 and cisplatin 20 mg/m2, and seven days later the patient underwent a left radical orchiectomy by an inguinal approach with left hemiscrotectomy, without complications. Following this intervention, serum alpha-fetoprotein (AFP) level was reduced to 350 ng/mL, and the human chorionic gonadotropin level was 50 IU/mL.
A postoperative biopsy showed a pure testicular teratoma () with glandular formations and the presence of cartilage (a) and respiratory epithelium, with ciliated columnar cells alternating with goblet cells (b).
The patient was discharged after showing clinical improvement to receive ambulatory chemotherapy.
The formula for computing Cockcroft-Gault is given by CrCl = ((140 - age) * adjusted weight * (gender_coefficient)) / (serum creatinine * 72), where the gender_coefficient is 1 if male, and 0.85 if female. The serum creatinine concentration is in mg/dL.
The patient's gender is male, which means that the gender coefficient is 1.
The patient is 26 years old. 
The concentration of creatinine is 0.9 mg/dL. 
The formula for computing the patient's BMI is (weight)/(height * height), where weight is the patient's weight in kg and height is the patient's height in m.
The patient's height is 1.75 m. The patient's weight is 98.0 kg. The patient's bmi is therefore 98.0 kg / (1.75 m * 1.75 m) = 32.0 kg/m^2.The patient's BMI is 32.0, indicating they are overweight/obese.
Because the patient is overweight/obese, we use the adjusted body weight formula to get the adjusted weight used for Cockroft-Gault Equation. Shown below is the computation for IBW (ideal body weight).
The patient's gender is Male.
The patient's height is 1.75 m, which is 1.75 m * 39.3701 in/m = 68.898 in. 
For males, the ideal body weight (IBW) is calculated as follows:
IBW = 50 kg + 2.3 kg * (height (in inches) - 60)
Plugging in the values gives us 50 kg + 2.3 kg * (68.898 (in inches) - 60) = 70.465 kg.
Hence, the patient's IBW is 70.465 kg.Shown below is the computation for ABW (adjusted body weight).
To compute the ABW value, apply the following formula: ABW = IBW + 0.4 * (weight (in kg) - IBW (in kg)). ABW = 70.465 kg + 0.4 * (98.0 kg  - 70.465 kg) = 81.479 kg. The patient's adjusted body weight is 81.479 kg.

Using the Cockcroft-Gault equation:
CrCl = ((140 - age) * adjusted weight * gender_coefficient) / (serum creatinine * 72).
Plugging the patient's values gives us ((140 - 26) * 81.479 * 1) / (0.9 * 72) = 143.343 mL/min. Hence, the patient's creatinine clearance is 143.343 mL/min.