Mucinous cystadenoma of the pyelocaliceal system: a report of 3 examples and an analysis of 17 previously published cases

Mucinous adenocarcinoma in kidneys with developmental anomalies - a report of two cases

BACKGROUND

Primary mucinous adenocarcinomas of the kidney are rare and pose a challenge for preoperative diagnosis. The histogenesis of these tumours remains largely unknown, with three proposed theories: chronic irritation, differentiation of celomic epithelium, and kidney maldevelopment. Here, we present two cases of renal mucinous adenocarcinoma in patients with developmental renal anomalies, specifically a duplex collecting system and a horseshoe kidney.

CASE PRESENTATION

First, A 50-year-old male presented with loin pain and jelly-like discharge in urine with a duplex collecting system and gross hydronephrosis of the upper moiety on imaging. The patient underwent upper polar nephrectomy with controlled drainage of 1.5 L of mucinous fluid. Histopathology was suggestive of mucinous borderline cystic neoplasm with invasive microcarcinoma. The patient presented one year later, with a hydronephrotic lower moiety of the left kidney and a rectus abdominis mass. Fine needle aspiration biopsy of the mass revealed papillary adenocarcinoma with histological resemblance to the renal pelvis lesion, establishing it as a metastasis from the primary renal malignancy. Second, A 53-year-old male who had undergone right laparoscopic cyst deroofing for a symptomatic renal cyst, whose postoperative histology revealed findings consistent with mucinous adenocarcinoma, presented with flank pain and palpable retroperitoneal mass. Imaging revealed a horseshoe kidney morphology with a large multilobulated hypodense non-enhancing cystic lesion arising from the right kidney. Cyst excision with right open radical nephrectomy was performed. Gross examination revealed multiple cystic spaces replacing renal parenchyma, filled with gelatinous material. Microscopy was suggestive of recurrent mucinous adenocarcinoma.

CONCLUSIONS

Renal mucinous cystadenocarcinomas can be associated with anomalous kidneys. Definitive diagnosis relies on histopathology, and these tumours are recognized for their aggressive nature. Complete resection is the preferred treatment, but further studies are needed to assess the efficacy of adjuvant treatment, given the poor prognosis and high likelihood of recurrence.

CLINICAL TRIAL NUMBER

Not applicable.

Primary mucinous tumors of the renal pelvis: Clinical, histopathological, and molecular analysis of three cases

Primary mucinous tumors of the renal pelvis are extremely rare and pose challenges in terms of diagnosis and treatment. This study reviewed the clinical and pathological characteristics of mucinous tumors of the renal pelvis, including mucinous cystadenocarcinomas and mucinous cystadenomas. Immunohistochemical analysis was conducted in three cases, along with KRAS gene detection using the Amplification Refractory Mutation System (ARMS) method. The results revealed mucinous epithelium with acellular mucinous pools in all cases, and acellular mucinous pools were observed in the renal parenchyma and perirenal fat capsules. All tumors expressed CK20 and CDX2, and one case showed KRAS gene mutation. The study suggests that mucinous cystadenomas of the renal pelvis may exhibit borderline biological behaviors. This study is the first to report a KRAS gene mutation in a mucinous cystadenoma of the renal pelvis, offering valuable insights into the diagnosis and treatment of this rare condition.

Nephron-sparing surgery for primary mucinous adenocarcinoma of renal pelvis in horseshoe kidney: A case report

RATIONALE

Mucinous adenocarcinoma of the renal pelvis is extremely rare in malignancy of the renal pelvis, and <100 cases have been reported so far. However, horseshoe kidneys appear to be more prone to this mucinous gland metaplasia. Due to the lack of a specific diagnostic basis, it is difficult to confirm the diagnosis before surgery, which is easy to cause misdiagnosis.

PATIENT CONCERNS

We report a 64-year-old male patient who found a cystic mass in the left kidney during physical examination. CT examination showed a horseshoe kidney with a cystic mass 9.5 × 8.0 cm in front of the left kidney, lacking obvious diagnostic features.

DIAGNOSIS

It was misdiagnosed as cystic teratoma before the operation, and was diagnosed as mucinous adenocarcinoma of the renal pelvis through pathological examination after the operation.

INTERVENTIONS

Resection of the tumor by nephron-sparing surgery and postoperative chemotherapy.

OUTCOMES

No tumor recurrence was found at 6 years of follow-up. After 7 years, the patient had multiple metastases in the abdominal wall and peritoneum, and no tumor recurrence was found in the urinary system. The patient received chemotherapy again and survived well.

LESSONS

The prognosis of nephron-sparing tumor resection for MRAP is not significantly different from that of radical nephroureterectomy + bladder cuff excision. Because it can reduce the risk that patients can not tolerate follow-up chemotherapy due to abnormal renal function after surgery, which may be more beneficial in patients with kidney abnormalities or chronic disease.

Parenchymal mucinous cystadenoma of the kidney: a case report and literature review

Background

Mucinous cystadenoma (MC) of the kidney is exceedingly rare. We found 22 similar cases in the literature. These masses are underdiagnosed due to radiologic similarities with simple renal cysts.

Case presentation

A 66-year-old man with a previous history of hypertension and anxiety was referred to our tertiary clinic with left flank pain. Ultrasound revealed a 60 mm-sized, complex cystic mass with irregular septa in the lower pole of the left kidney (different from last year's sonographic findings of a simple benign cyst with delicate septa). CT scan showed the same results plus calcification. Due to suspected renal cell carcinoma, a radical nephrectomy was performed. Postoperative histopathologic examination revealed a cyst lined by a single layer of columnar mucin-producing cells with small foci of pseudo-stratification, consistent with the MC’s diagnosis. The first follow-up visit showed normal blood pressure without medication and no flank pain and anxiety after a month.

Conclusion

It is quite challenging to distinguish the primary MC of the kidney from a simple renal cyst based on clinical and imaging findings. The radiologic features of these entities overlap significantly. Thus, complex renal cyst and renal cysts with mural nodules should be followed closely to detect malignancy earlier.

Primary mucinous adenocarcinoma of the renal pelvis misdiagnosed as calculous pyonephrosis: a case report and literature review

Primary mucinous adenocarcinoma of the renal pelvis is a rare malignant disease that is difficult to diagnose preoperatively. There are still no characteristic symptoms, radiological features, or standard treatment for this tumor with only ~100 cases reported. The prognosis is poor. We report a case of a 66-year-old man who presented with a 2-month history of fever and right waist pain. He was misdiagnosed with calculous pyonephrosis and underwent percutaneous nephrostomy (PCN) at a local hospital. Gelatinous material was drained via a PCN catheter. He was then transferred to our hospital. He had elevated CEA and CA19-9. We performed an open radical nephrectomy and found polypoid, gelatinous material and stones filling the renal pelvis. He was diagnosed with primary mucinous adenocarcinoma of the renal pelvis by pathology. He refused adjuvant chemotherapy and there was no sign of recurrence after one year of follow-up. By assessing a literature review of all of the cases reported since 2000, we recommend that careful history taking, serum tumor markers, and CT scans may improve the diagnostic accuracy rates and radical nephrectomy with total ureterectomy accompanied by adjuvant therapy may improve the prognosis.

Mucinous cystadenoma of a horseshoe kidney: A case report and literature review

A 45-year-old man complained of a palpable mass in his left abdomen. Computed tomography showed a horseshoe kidney with a Bosniak type II complicated cyst from a left segment. Three years after his initial examination, due to the growing cystic lesion and the compression imposed on the urinary collecting system and surrounding organs, we performed a left heminephrectomy. The diagnosis was mucinous cystadenoma of the kidney. No recurrence was observed 6 months after surgery. The histopathology was unique since the inner surface of the cyst was covered by a mucin-positive columnar epithelium connected to a urothelium, with continuous transition between the two. This suggests that the mucinous tumour may have originated from a sequestered segment of the renal pelvic epithelium in the renal parenchyma.