An extremely rare case of renal myxoma
The most common location of myxoma is the skeletal muscle and its occurrence in the kidney is a rare event. Myxoma of the kidney is most commonly located in the parenchyma, and capsular involvement is extremely rare. The following case has been published in the journal Urology Case Reports.

A 56-year-old man presented with a 6 month history of vague right flank pain and hematuria one day prior to admission. There had been no history of trauma, dysuria and fever. The only positive history was hypertension and he was under treatment with amiodarone. Physical examination was negative and no tenderness or mass was detected.

Urinalysis revealed micro-hematuria and urine cytopathology was negative for malignancy. Abdominopelvic ultrasonography showed a large hyperechoic mass in the lower pole of the right kidney, according to the presence of fat content, the possibility of angiomyolipoma was suggested.

Abdominopelvic CT scan demonstrated a large heterogeneous hypodense to isodense mass in the lower pole of the right kidney containing fat in some parts of the mass that showed mild enhancement after administration of contrast material. A few para-aortic subcentimeter lymph nodes up to 8mm were also noted. The patient underwent right partial nephrectomy through midline abdominal incision with the preoperative diagnosis of renal cell carcinoma.

Microscopically, the tumor cells revealed inconspicuous border and oval nuclei with inconspicuous nucleoli. Mitotic activity was absent and there was no atypia. Immunohistochemistry was performed to confirm the diagnosis which revealed only positive vimentin. Cytokeratin, desmin, HMB45, S-100, and SMA were all negative. Proliferative activity (Ki-67) was negative.

With the above findings, diagnosis of myxoma was confirmed. Now after six months of follow-up, the patient is well and completely symptom-free.

Key takeaways:-
- Diagnosis of this rare and benign tumor, we can benefit from preserved unaffected kidneys and reduce the surveillance costs after nephrectomy.

- Advanced imaging models such as CT guided biopsy and PET (positron emission tomography) can help us to get closer to the diagnosis, but for definitive diagnosis, we need immunohistochemistry evaluation.

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