Renal Myxoma- A Rare Variety of Benign Genitourinary Tumour

Report of two primary renal tumors with myxoid features. Differential diagnosis between benign and malignant entities

Renal mesenchymal neoplasms are rare entities which can have a benign or a malignant behavior. Herein we describe two renal mesenchymal tumors with myxoid stroma, investigating the wide spectrum of differential diagnosis. With our first case we considered some benign entities such as myxoma, myxoid leiomyoma, and mixed epithelial and stromal tumor; with our second case we considered some sarcomas with myxoid features such as myxofibrosarcoma, low-grade fibromyxoid sarcoma, dedifferentiated liposarcoma, and myxoid liposarcoma. During the diagnostic process, it is important to integrate histopathological, immunohistochemical, and molecular data in order to avoid misdiagnosis. We concluded our second case report was a myxofibrosarcoma grade 1. To the best of our knowledge, we described the fourth primary renal myxofibrosarcoma reported in literature.

Renal myxoma: An unforeseen diagnosis

Myxomas are rare tumours that can be found in many anatomical locations. There are only 17 cases of renal involvement documented. Our case is an 85 year-old man followed in our consultation with recurrent hematuria after a transurethral resection of a bladder tumour. Evaluation with CT showed a solid lesion with 23 x 18 mm partially obliterating the left inferior calyx. The patient underwent a left nephroureterectomy. Microscopic examination showed a mass within renal parenchyma adjacent to the renal pelvis composed of plump mildly atypical spindle cells distributed in a copious myxoid matrix. Immunohistochemical staining for Vimentine, Pankeratin (AE1/AE3-), CD34, CD31 and smooth muscle actin were negative. With these histopathological and immunohistochemical findings, the case was diagnosed as renal myxoma.

Myxoma of the renal pelvis masquerading pelviureteric stenosis: conservative limited resection with renal preservation: case presentation and literature review

BACKGROUND

Myxoma is a relatively rare mesenchymal tumor seen mainly in the heart and skin. Renal myxomas in particular are exceptionally rare where only 17 cases were previously reported in the English Language literature. Only 2 of the 17 reported cases were located in the renal sinus/pelvis.

CASE PRESENTATION

This is a case of an 18-year-old male patient who complained of right, colicky flank pain associated with abdominal pain and discomfort. Imaging findings revealed right kidney hydronephrosis with a provisional diagnosis of pelviureteric junction (PUJ) stenosis. On computed tomography, there was a very faint thin walled mass abutting the calyces, camouflaged within the dilated renal pelvis. During surgery, a polypoid mass was found at the pelviureteric junction, causing the obstruction. Histological examination showed a hypocellular, paucivascular myxoid neoplasm, with few spindle cells displaying serpentine nuclei and inconspicuous nucleoli. The tumor cells expressed immunoreactivity for vimentin, but not for S100, CD34, actin, or desmin. This will qualify as the third case of renal pelvis myxoma.

CONCLUSION

Myxomas in the renal pelvis/sinus are extremely rare and can present with hydronephrosis and subtle radiological findings mimicking a PUJ stenosis. Being aware of this entity can save the patient unnecessary nephrectomy with possible preservation of the kidney.

Myxoma of the kidney - an unusual benign renal tumor: a case report

BACKGROUND

Myxomas are rare benign soft tissue tumors. The kidney is an unusual location for this tumor. For this reason, less than 15 cases of renal myxoma have been reported in the English literature. There are no specific clinical and radiological features reported for this tumor that allow a preoperative diagnosis enabling a conservative treatment.

CASE PRESENTATION

We report another case of renal myxoma found in a 50-year-old Moroccan woman who presented with a right dull flank pain. An abdominal computed tomography scan objectified a suspected malignant renal mass. Thus, radical nephrectomy was performed. Histopathology of the specimen revealed the typical appearance of a myxoma.

CONCLUSIONS

The objective of this report is to add another case report of this rare benign renal tumor to the literature. This benign tumor with excellent prognosis has no specific preoperative features that could justify a conservative management; a radical approach remains the therapeutic option for now.